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MethodsX
MethodsX
MethodsX
2215-0161
Elsevier

S2215-0161(24)00364-9
10.1016/j.mex.2024.102912
102912
Materials Science
Composites formed by layered double hydroxides with inorganic compounds: An overview of the synthesis methods and characteristics
Velázquez-Herrera Franchescoli Didier franchescoli.velazquezher@correo.buap.mx
a⁎
Zarazua-Aguilar Yohuali b
Garzón-Pérez Amanda S. c
Álvarez-Gómez Karin Monserrat d
Fetter Geolar geolar.fetter@correo.buap.mx
a
a Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla. Ciudad Universitaria, Puebla, PUE, Mexico
b Unidad Académica Profesional Acolman, Universidad Autónoma del Estado de México, Acolman, Edo Mex, Mexico
c Instituto de Metalurgia, Universidad Autónoma de San Luis Potosí, San Luis Potosí, SLP, Mexico
d Instituto de Ciencias-Zeolitas, Benemérita Universidad Autónoma de Puebla, Ciudad Universitaria, Puebla, PUE, Mexico
⁎ Corresponding author. franchescoli.velazquezher@correo.buap.mx
20 8 2024
12 2024
20 8 2024
13 10291223 2 2024
13 8 2024
© 2024 The Author(s)
2024
https://creativecommons.org/licenses/by-nc/4.0/ This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/).
Review Highlights

• Various synthesis routes of hydrotalcite/inorganic compounds composites are described.

• The synthesis route allows generating different morphologies of the composites.

• The composites obtained exhibit multifunctional properties for different applications.

Nowadays, layered double hydroxides (LDH), sometimes referred as hydrotalcite-like compounds, have gained great attention since their composition and structure can be easily modified, so that they can be implemented in multiple fields. LDH-based composite materials based on LDH exhibit tremendously improved properties such as high specific surface area, which promotes the accessibility to a greater number of LDH active sites, considerably improving their catalytic, adsorbent and biological activities. Therefore, this review summarizes and discusses the synthesis methods of composites constituted by LDH with other inorganic compounds such as zeolites, cationic clays, hydroxyapatites, among many others, and describe the resulting characteristics of the resulting composites, emphasizing the morphology. Brief descriptions of their properties and applications are also included.

Graphical abstract

Image, graphical abstract

Keywords

Hydrotalcites
Anionic clays
Synthesis
Morphology
Sustainable materials
Method name

Methods for the synthesis of composites
==== Body
pmcSpecifications TableSubject area:	Materials Science	
More specific subject area:	Clays’ composites	
Name of the reviewed methodology:	Methods for the synthesis of composites	
Keywords:	hydrotalcites, anionic clays, synthesis, morphology, sustainable materials	
Resource availability:	NA	
Review question:	1. What is a layered double hydroxide?

2. What inorganic materials have been used to form composites with layered double hydroxides?

3. What synthesis methods have been used to obtain LDH composites with inorganic materials?

4. What morphological characteristics do these composites present?

5. What applications have been given to LDH composites with inorganic materials?

	

Background

LDH belong to the group of clay minerals of anionic type (anionic clay) also known as hydrotalcite-like compounds, hydrotalcites, mixed metal hydroxides [1], or more recently, layered double metal hydroxides [2] or double metal hydroxides [3], and if it contains rare earth elements are known as layered rare-earth hydroxides (LRH) [4]. They are natural or synthetic clays have the ability to compact upon losing water molecules, resulting in macroscopic cracking as shown in Fig. 1. Additionally, they exhibit a two-dimensional layered structure based on brucite (Mg(OH)2), with octahedral coordination around the metal ions [5]. The general chemical formula is [M2+(1-x)M3+x(OH)2](Xm−(x⁄m))·nH2O, where M2+ and M3+ are divalent and trivalent cations, x represents the metal ratio M3+/(M3++M2+), and n is the number of water molecules [6,7].Fig. 1 Image of a resulting dried LDH after the ultimate step of synthesis.

Fig 1

The divalent metal ions can be substituted isomorphically by trivalent ions of similar coordination properties so originating a positively charged sheet. These metal ions are strongly bonded via covalent bonds, which are electrically neutralized by compensating anions (Xm−) within the interlayer galleries [8]. They are bonded to the layers by Coulomb and van der Waals interactions, and by hydrogen bonds [9]. The water molecules inside of galleries are bonded to the layered OH ions and/or with the anions in a highly disorganized way [10], as represented in Fig. 2.Fig. 2 Layered double hydroxide structure representation.

Fig 2

Frequently, divalent metal ions are those whose ionic radii vary between 65pm (Mg) and 80pm (Mn), whereas the radii of the trivalent metal ion has to be comprised between 50pm (Al) and 69pm (Cr) [11] with the most frequently divalent cations constituting the LDH structure being Fe2+, Co2+, Zn2+ or Cu2+and, as trivalent cations, Al3+, Fe3+ or Ga3+ [[12], [13], [14]]. Still, some unusual cations have been introduced in the LDH lamellae such as La2+[15], Ce2+ [13], uranyl (UO22+) [16], Zr2+ [17], Ru3+ [18], Rh2+[19] and Sn2+ [20], among others. LDH composed by three or more types of cations forming the lamellae have also been reported, for example, in CuZnAl- or FeZnMgAl-LDH [[21], [22], [23], [24], [25], [26], [27]]. In addition, cations with a coordination number greater or lesser then 2 or 3 have also been used to form LDH, such as Zr4+ [28,29], Sn4+ [30] and Ti4+[31] or Li+ [32]. Some cations that present a Jahn-Teller effect, such as Cu2+ and Mn3+, can only be part of the LDH lamellae when associated with other type of cation [33,34].

Regarding the anions that can be part of the LDH structure, there is practically no limits in terms of sizes and charges. Commonly, the typical compensation anions are, in order of affinity, CO32->SO42->OH->F->Cl->Br->NO3->ClO4- [[35], [36], [37], [38]]. Many other inorganic and organic anions, or even compounds with negative charge density, have been reported in the literature, such as 131I– [39], hemoglobin [40], DNA [41], siRNA [42] or papain [43]. In normal conditions of LDH synthesis, it is difficult to obtain a solid free from CO32- cations considering that its formation is generated from the atmospheric CO2 absorbed on the basic reaction medium. LDH free of carbonates are normally obtained only when synthesized in inert atmospheres. Recently, Velázquez-Herrera and Fetter [3] reported the possibility to form LDH containing a heterogeneous distribution of two different type of anions, these materials finding important applications in the pharmaceutical field as a vehicle of successive drug-liberation.

Pure LDH are often only obtained when the M2+/M3+ metal molar ratio is between 2:1 and 4:1 (or 0.2 < x < 0.33) [44]. Exceptions have been recently reported concerning metal molar ratios of 0.5 [45], 1 [46], 5 [47], 6 [48], 7 [49], 8 [50], 9 [50], and 10 [48], but, in many cases, the presence of other compounds as impurities were detected. The pH of the synthesis medium also influences the formation of pure LDH. The optimal pH values run from 8 to 10, depending on the LDH composition, but pH's lower than 6 or higher than 10 have also been reported [[51], [52], [53]].

LDH synthesis methods, Scheme 1, include simultaneous coprecipitation, sol-gel method, spontaneous combustion, urea hydrolysis, electrochemical, reverse microemulsion, among others [[54], [55], [56]]. The most widely used method is simultaneous coprecipitation, due to its process simplicity and the stoichiometric control of the cations integrated to the structure, as well as its reproducibility [54].Scheme 1 Synthesis methods of the LDH.

Scheme 1

The simultaneous coprecipitation method consists of a slow addition of a mixed solution of divalent and trivalent metal salts in adequate proportions with a second solution (alkaline solution) into a reactor containing water at a selected pH value, followed by a hydrothermal treatment of crystallization, filtering, washing, and drying [51]. Commonly, the hydrothermal treatment is used to increase yields, to promote the LDH crystallization and to control the crystal sizes. Among the hydrothermal treatments, the conventional method of stirring the reaction mixture at specified times and temperatures, is the most used [57], but much more current crystallization techniques such as microwave irradiation [58,59] and ultrasound [21,60], or simultaneous irradiations (ultrasound/microwave) [61], have improved the production of these materials. Currently, there has been a trend towards developing environmentally friendly preparation methods for LDHs, which offer significant advantages in terms of solvent usage, processing times, and environmental contamination. These methods avoid the demanding conditions such as high energy consumption and the need for working under an inert atmosphere. These techniques include: mechanochemistry [62], electrocoagulation method [63], and one-pot method [64].

After the synthesis process, most of the time, LDH are calcined to improve some properties, such as dielectric and conductive properties [65], the specific surface areas or to generate active sites [66]. Calcining at temperatures higher than 600 °C, the LDH become crystalline spinel-like oxides, but, at temperatures between 400 and 600 °C, mixed oxides or double metal oxides are formed [2,67,68]. One of the most important characteristics of the mixed oxides occurs when they are placed in contact with anions in water solution, giving rise to a LDH structure regeneration process known as the “memory effect" [[69], [70], [71]].

Regarding some physical characteristics of LDH (Scheme 2) such as morphology and texture they can be controlled mainly by the conventional coprecipitation method followed by hydrothermal treatment with microwaves, ultrasounds and combined treatments have been described. For example, the increase in area follows the trend of microwave < ultrasound < conventional [21,72,73]. Concerning the anion exchanger properties, LDH have an anion exchange capacity between 200 and 450 mmol/mg, which depends on the metallic cation ratio [74]. Another important property of LDHs is their particle sizes. Nanosized particles can be obtained from the delamination of the material in colloidal form [75,76]. Zeta potential of the LDHs plays an important role in the measurement of charge density and their stability in water as a function of pH [76] having an elevated positive surface charge in the range of +10 to +75 mV [77,78] in pHs between 4 and 12. However, it has been reported that it can become negative at pHs above 10 [79] or by electrostatic phenomenon [80]. The LDH thermal stability depends on the chemical composition which is dependent on the cation nature and content in the lamellae as well as the nature and content of the interlayer anions [74,81,82]. Regarding to the LDH toxicity, that containing heavy metals such as Cr or Co usually present some cytotoxicity, but the major common compositions based on Mg and Al have no toxicity [83,84] and, contrarily, they have some benefits to the human health, for example, the solid milk of magnesia commercially available pills used to neutralize stomach acidity [85].Scheme 2 LDH physical characteristics.

Scheme 2

Morphologically, LDH crystallites have often a hexagonal form of stacked flakes [86], as shown in the micrograph taken at X25000 (Fig. 3). Also, LDH particles in the form of three-dimensional ordered microporous [87] or spherical shapes have been synthesized [88]. Also, rounded nanoparticles in colloidal systems have been reported [75,89].Fig. 3 SEM image of a hexagonal-shaped crystallites of Mg-Al LDH. Copyright 2011, reproduced with permission from reference [86].

Fig 3

Considering all aspects of the LDH materials mostly related to the design or modification of the chemical composition and structure, besides being environmentally friendly [90] and nontoxic to humans [36], they come into a class of multifunctional materials able to be used in many applications such as catalysts [10,[91], [92], [93], [94]], adsorbents of pollutant compounds [95], antibacterial materials [[96], [97], [98], [99]], containers for drug delivery [100], medical applications [101,102], analytical chemistry [103], among others [104,105]. On the other hand, they are currently being applied for environmental benefit, such as Fenton-based oxidation processes for water and wastewater treatment [106], degradation of organic and inorganic pollutants [107,108] and conversion of biomass-derived molecules [109].

In addition, considering the chemical composition and structural versatility of the LDH materials, the development of a new family of sustainable inorganic composites involving two inorganic materials has recently been reported in the literature. Usually, composites are prepared combining materials with different properties to obtain, for example, an acid-basic material, or to enhance the materials specific surface areas to improve their adsorption or catalytic properties [110]. Briefly, the presence of LDH as a component of composites forming LDH/inorganic compound composites makes it possible to obtain special materials with enhanced physicochemical and textural properties, and thus, being able to be applied in many fields from industrial to quotidian life.

In view of this, the present systematic review will disclose the principal inorganic compounds employed in the formation of LDH/inorganics composites, their synthesis methods, and the characteristics and properties resulted from their combination. Finally, it highlights the given applications of these materials. This review would be highly beneficial in encouraging future research by novice researchers seeking to delve into the field of clays and their combination with inorganic materials, thereby generating new materials that could have very innovative applications. Thus, this review stands out from others by exploring synthesis methodologies used to produce inorganic composites and explores their applications in science and technology with environmental sustainability in mind.

Composites description

At the present, the inorganic materials that have been combined with LDH to form composites are SBA-15, zeolite, hydroxyapatite, titania, montmorillonite, vermiculite, halloysite, kaolinite, sepiolite, laponite, palygorskite, silica, alumina, magnetite, and some metallic salts, as summarized in Scheme 3. Some brief description of each one, as well as the characteristics and applications of the resulting LDH/inorganic composites are described below:Scheme 3 Inorganic materials that have been used to form composites with LDH.

Scheme 3

LDH/SBA-15 composites

One type of mesoporous silica material is known as SBA-15, labeled by its developers and means Santa Barbara Amorphous Number 15 [111]. It is a highly ordered hexagonal mesoporous silica structure synthesized by using commercially available block-copolymer surfactants in strong acid media [112]. It possesses a specific surface area larger than 700 m2/g and a 0.8 cm3/g of pore volume [113] in two-dimensional hexagonal (space group p6mm) silica-block copolymer mesophases with unidirectional mesoporous channels having 6.0 – 7.0 nm of diameter [111,112]. Some characteristics that make this material unique are the high thermal and chemical stability, high specific surface area, and homogeneous pore sizes [114]. Furthermore, the SBA-15 material is of a nontoxic nature, presenting excellent biocompatibility and biodegradability, in addition to the facile functionalization with different organic-inorganic groups [[115], [116], [117], [118], [119]]. All these characteristics make SBA-15 an attractive material to combine with LDH to improve the properties of both materials.

The synthesis process of this type of composites involves many methods which are described below:1. The most commonly used method is known as in situ method [113,116,117,[120], [121], [122], [123], [124]]. It consists of dispersing a certain amount of calcined SBA-15 in water. Subsequently, the reactants to form a LDH are added to the SBA-15 aqueous dispersion followed by a hydrothermal treatment with microwaves, ultrasound, or by a conventional method to promote the LDH crystallization. Finally, the obtained solids are filtered, washed with deionized water, and dried. This method promotes the formation of LDH particles located inside the SBA-15 pores and over its external surface [117,120].

2. Another synthesis method consists in preparing the LDH gel separately, mixing it with a SBA-15 dispersion, and then treating the mixture with ultrasound to promote the integration of one material with the other [125]. The resulting composites were formed with different LDH proportions, but, in all cases, the LDH component was dispersed in the form of nanocrystals over the external surface of the SBA-15 material. No destruction of the SBA-15 framework was detected.

3. Another synthesis method, known as gel mixing method, is based on preparing a gel of both compounds, mixing them and bringing under a crystallization stage [126,127]. The gels mixing method results in composites with a homogeneous distribution of both components.

4. The simultaneous synthesis method comprises preparing an SBA-15/LDH composite by mixing the Pluronic P123 with the LDH precursors salt solutions in diluted HCl solution, and then adding the TEOS reactant. The resulting mixture is then stirred, followed by a conventional crystallization stage [118,128,129]. This method generates composites with uniform distribution of the LDH crystals incorporated into the pores of the SBA-15 component. Fig. 4 shows the TEM micrographs of the composite obtained by this method. In it, the hexagonally arranged cylindrical pores of SBA-15 can be observed, with no evidence of LDH presence, suggesting that it is located inside the pore channels [118].Fig. 4 TEM micrographs of (a − c) SBA-15 and (d − f) MAZ-1/SBA-15 nanocomposites. Copyright 2019, reproduced with permission from reference [118].

Fig 4

5. One more method is by the addition of a magnesium methoxide solution on a previously synthesized Al-SBA-15 and stirring for a short time [130]. The resulting composite was formed by flake-shaped SBA crystallites, while the LDH component remains as crystallites supported on the surface of the SBA-15 particles.

All these synthesis methods generate acid-basic composites with improved LDH textural properties. This kind of composites have been used as adsorbents of CO2 [116,120], water vapor [110], BTEX [113], heteropoly acids [117], organic compounds [113,127], and heavy metals [121]. In catalysis, they promote many reactions such as chromenes [125] and pyrans [117] syntheses, biodiesel production [118] and hydroisomerization of olefins [126].

LDH/zeolite composites

Zeolites are natural or synthetic crystalline aluminosilicate microporous solids having the general formula Mx/n(AlO2)x(SiO2)y, where n is the oxidation number of the cation M, x and y are the total number of tetrahedra per unit cell, and y/x the Si/Al atomic ratio [131,132]. Zeolites are formed by a three dimensional negatively charged framework structure built from TO4 tetrahedra (with T = Si, Al, P, Ge, B, Zn, Mg) in structures that enclose channels and/or cavities with nanometric diameters [131]. These cavities are connected by channels that contain hydrated cations, which neutralize the negative charged zeolite framework [133]. Due to their regular microporous structures, zeolites have "molecular sieving" properties [132,134,135].

Zeolites can be classified according to different criteria: the dimensions of the pore apertures [132], the dimensionality of their channels, and the possibility to modify the hydrophilic character [136]. Their synthesis can be carried out under different conditions, with the Si/Al ratio, the water amount, the cations type, the temperature, pressure, and time being the most frequent variables. With these variations, different kinds of zeolites with different compositions, crystal sizes and morphology can be obtained [131].

Commonly, zeolites present very high surface areas and pore volumes that can host a great amount of reversibly adsorbed water. Furthermore, due to their cationic exchange property, the cations can generally be easily exchanged for others of a similar nature [134]. Besides, the cation exchange properties of zeolites can also be useful in terms of catalytic applications [137]. The replacement of the original cations by protons or transition metals results in the creation of strong acidic sites for acid or redox catalyzed processes [131].

Considering that zeolites are acidic solids [138], the combination with a material with basic character, such as LDH, could result in interesting composites having the dual acid-basic character. The most common zeolites used in combination with LDH are ZSM-5, Y, A, and X.

The LDH/zeolite composites can be synthesized by different methods. They are:1. Synthesizing and crystallizing LDH on a zeolite dispersion. In one case, the resulting composite are constituted by NiAl-LDH lamellae uniformly dispersed over the Y zeolite particles, exhibiting a typical spheroidal rose-like arrangement [139]. In another case, the MgAl or CaAl-LDH are dispersed in the form of small lamellae over a ZSM-5 zeolite. The Fig. 5 shows the morphology of the composite obtained in this latest methodology, where the presence of zeolite is identified by large prismatic crystals, while the LDH is identified by the observation of uniformly flower-like shaped edges [140].Fig. 5 SEM pictures of (A) ZSM-5 calcined, (B) ZSM-5-NH3, and (C) LDH/ZSM-5 composite. Copyright 2019, reproduced with permission from reference [140].

Fig 5

2. Powdered zeolite mixed with the LDH precursor metal salts and then mixed with a NaOH solution [141,142] or a urea solution [[143], [144], [145]], generates composites where the LDH in the form of rough layers covering the zeolite surfaces. The arrangement of the components in the composite is independent of the LDH or zeolite type.

3. Simultaneous synthesis of both components, i.e., mixing the precursor solutions of both components [146]. This method generates a composite where the MgAl-LDH crystals are attached to the ZSM-5 zeolite particles.

4. Mixing the powdered zeolite and the powdered LDH in water, evaporate the solution to form a dry gel and treat it with water steam [146]. The resulting composite exhibits MgAl-LDH crystals on the surface of the ZSM-5 zeolite particles.

5. Direct synthesis of LDH/zeolite from red mud waste of the alumina obtention process [147] or mine waste from the production of copper [148]. This method favors plate shaped crystals of LDH located on the LTA zeolite surface.

6. Mixing the powdered zeolite with non-crystallized LDH and bringing them under a conventional hydrothermal treatment [149,150]. The resulting solids consist of Y zeolite particles covered by NiAl- or CoAl-LDHs in the form of a flower-like arrangement.

7. Crystallizing LDH and zeolite at the same time from a mother liquor of an X or A zeolite precursor solution [151,152]. This method generates composites where the zeolite exhibits a morphology of cubic crystals with defined edges, while the LDH shows a series of hexagonally plate-like particles as shown in the Fig. 6 [152].Fig. 6 Micrograph of the composite ZAHD (a,b) material compared to zeolite A (c) and LDH (d). Copyright 2019, reproduced with permission from reference [152].

Fig 6

8. Dipping zeolite particles on a colloidal suspension of LDH and treating with ultrasound irradiation [153] or conventional hydrothermal treatment [154]. The resulting composites are constituted by monolayers of MgAl-LDHs located on the ZSM-5 zeolite surface.

9. Mixing a dispersion of LDH with a dispersion of zeolite Y, followed by a hydrothermal treatment to well-disperse the materials, generating solids where the LDH is dispersed on the surface of the zeolite [155].

Some of the LDH/zeolite composites have found applications as adsorbers of CO2 [140,151,154], toluene [156] or dyes [147]. As catalysts, some of them are used in CO2 methanation [139], cyanobacteria pyrolysis [143], bio-oil production [144], reduction of NOx [150], Glaser Homocoupling reaction [155] and m-phenylenediamine obtaining [149]. In addition, some LDH/zeolite composites catalysed reactions of synthesis of dyes [141], benzoin ethyl ether [142] and 5-hydroxymethylfurfural [146].

LDH/hydroxyapatite composites

Hydroxyapatite (HAp) or hydroxylapatite [157] is the most usual form of calcium phosphate biocrystal [158] with a hexagonal structure (P63/m space group) and the lattice parameters a = 9.37 Å and c = 6.88 Å [159]. It is formed by calcium, phosphate and hydroxyl groups according to the formula Ca10(PO4)6(OH)2 having a Ca:P molar ratio of 10:6 [157]. In this material, the hydroxyls can be replaced by other anions such as Cl- or F-, originating compounds named as chlorapatite or fluorapatite [157]. Otherwise, they can also retain cations such as Co2+,Cd2+, Sr2+, and Pb2+in their structure if these cations are present in acidic solutions [158,160,161].

HAp is the inorganic component of mineral bone that can be successfully obtained from various sources, such as mineral rocks or animal bones. They can also be obtained from biogenic products such as eggshells and mussel shells, among others [159]. Furthermore, it is the most attractive material for bone implantation, due to its similarity in composition with human bones.

Synthetic HAp can be produced by different methods, such as co-precipitation or sol-gel followed by a crystallization step that consists in a treatment with ultrasound, microwave irradiation, or by conventional heating [162,163]. The co-precipitation method with calcium and phosphorous precursor solutions at controlled temperature and pH is the most used [164]. By varying the synthesis methods and their conditions, HA with different characteristics can be obtained, thus originating materials with high surface area and porosity, so promoting their adsorption capacities. Also, the acid-base character, thermal stability and mechanical resistance can be adjusted by changing the synthesis conditions [157,159,161,165].

Considering this, hydroxyapatite is an excellent material to form composites with LDH, improving the characteristics and properties of both initial materials.

LDH/HAp composites can be obtained by different methods, as summarized below:1. Co-precipitation of HAp over a dispersion of powder LDH [166]. By this method, the formation of large HAp particles over a crystallized LDH is obtained.

2. Crystallizing LDH on previously synthesized HAp [71,166,167]. The resulting composites are formed by small LDH particles well dispersed over the HAp surface.

3. Simultaneous synthesis of both materials by mixture of the precursors [90,166,167]. The resulting composites are characterized by a homogeneous combination of very small particles of both components forming a cloud-like network arrangement.

4. Simultaneous hydrothermal treatment of the gels of LDH and HAp [164,[168], [169], [170]]. The resulting composites present micrometer-sized agglomerates of poorly crystallized LDH and HAp. The Fig. 7 shows the micrograph of the composite obtained by this method, where low crystallinity is observed with particles ranging in size from 1 to 5 nm [169].Fig. 7 Micrographs and semi-quantitative elemental analysis (at%) of the synthesized LDH-HAp samples (LDH-HAp). Copyright 2018, reproduced with permission from reference [169].

Fig 7

5. Mechanical mixture of nano-powder LDH with a dispersion of powder hydroxyapatite [2,171]. This method generates a physical mixture of both materials in a heterogeneous distribution of particles, where the LDH component is dispersed in the form of small particles located in the intergranular spaces of the large HAp grains.

6. Mixing the HAp with LDH gels, followed by a hydrothermal treatment [172,173]. By this method, the HAp particles are covered by sheet-like crystals of LDH uniformly dispersed in terms of quantity and size.

7. Generating HAp over the LDH by reacting Na2HPO4 with CaFe-LDH [174] or Na3PO4 with CaAl-LDH [160,175,176]. By this method, the LDH surface is covered by needle-like crystals of hydroxyapatite distributed uniformly over the lateral surface of the platelet-like LDH particles.

Thus, the composites constituted by the combination of LDH with HAp result in multi-functional materials [166] that have found many applications in different fields. As adsorbents they are used in (Cr2O7)2- [164], F- [71], Cl- [167,177], (UO3)6- [168,175], PO₄³⁻ [174], or dyes [2] retention. They also present properties as drug delivery carriers [160] and as catalyst in the transesterification of soybean oil [169,171,178], oxidation of glucose [176], chromene synthesis [166] and a cross-linking reaction of epoxy resins [172]. They also show high activity as antibacterial materials [90] with potential use as implants for osteo-reconstitution that prevent bacterial infections at the same time [173].

LDH/titania composites

Titania (TiO2) is a low cost, nontoxic, low cost, negative conduction band, naturally abundant, and highly stable compound with a semiconducting property [179,180]. This material has been used in photocatalytic processes, for example, for removal and oxidation of various organic pollutants in waste water [181]. TiO2 crystallizes in three systems: anatase, rutile, and brookite. Its photocatalytic activity is attributed to the presence of a wide band-gap from 3.03 eV for the rutile phase, to 3.18 eV for the anatase phase. In particular, the anatase form is excellent for photocatalytic processes, although this material suffers from electron recombination [182]. Titania also presents a great ability to produce powerful oxidants (holes in the valence band) and reductants (electrons in the conduction band) by absorbing photons from the UV region [182,183]. Besides, titania is a high hydrophobic material [184] and, due to this property, the reactions catalyzed by titania have the disadvantage of reducing its catalytic activity when being processed in an aqueous medium [185]. Also, as TiO2 nanoparticles are difficult to separate from the reaction medium, it has been proposed by many researchers [184] to immobilize it on appropriate materials, such as LDH, to promote their separation by filtration after a photocatalytic process. Supporting nanoparticles of TiO2 also contribute to have better regeneration of the photocatalyst [185], by hindering the recombination of e--h+, and thus, increasing the efficiency of the photocatalytic degradation of contaminants [184,186].

Several methods have been proposed to combine titania with LDH:1. Simultaneous co-precipitation of both components from the metal salts solutions in the presence of a basic solution, followed by a conventional crystallization step [181,182,184,[186], [187], [188], [189], [190], [191], [192], [193], [194]]. In general, the resulting composites are characterized by a random dispersion of TiO2 nanoparticles on the LDH surface forming agglomerates with a spongy appearance.

2. Mixing powder LDH previously dispersed in a basic solution and mixed with powder TiO2, followed by a hydrothermal treatment to well-disperse the materials [185,195,196]. A variation of this method consists of mixing the powder TiO2 with a LDH in its colloidal form [197], generating solids where the titania phase is dispersed on the surface of the LDH.

3. Mixing a titania dispersion with a LDH gel and treating the mixture by conventional heating [179,[198], [199], [200]]. This method generates the agglomeration of LDH nanoflakes on TiO2 nanotube particles, as shown in the Fig. 8 [179].Fig. 8 (a) SEM image of TiO2, (b, c, d) SEM images of LDH/TiO2 composite. The figures in the upper left corner are magnified views. Copyright 2018, reproduced with permission from reference [179].

Fig 8

4. Crystallizing titania on LDH previously dispersed in water or ethanol [183,[201], [202], [203]]. The resulting composites are formed by TiO2 nanoparticles randomly distributed on the surface of the LDH platelets.

5. Mechanical mixture of LDH with TiO2 powders by a kneading method [204]. In this case, a composite was constituted by a heterogeneous mixture of both components.

Generally, all synthesis methods lead to LDH/TiO2 composites having improved properties, useful for photocatalytic purposes such as the photodegradation of dyes [186,[188], [189], [190], [191],203], drugs [185,205], surfactants [184,187], and organic compounds [[181], [182], [183],202,204,206]. Furthermore, they have been successful applied in photocatalytic reduction of heavy metals [196], NOx [201], and CO2 [194,197,207]. Moreover, LDH/TiO2 composites are active as bactericide materials [195] or in photocathodic protection [179] as well as in photoanode construction [198].

LDH/montmorillonite composites

Montmorillonite (MMT) is a natural clay that belongs to the smectite group (2:1 dioctahedral smectite) [208,209], thus being composed of two layers of tetrahedra silicon oxide combined with a central octahedral aluminum oxi-hydroxide layer [210,211] having the chemical formula Mx(Al4–xMgx)Si8O20(OH)4, where M is a monovalent cation and x the degree of isomorphous substitution which can range between 0.5 and 1.3 [212]. The surface of the MMT is negatively charged due to isomorphous replacement of Mg2+ for Al3+ in the octahedral layers. This negative charge is usually balanced by alkaline earth cations (Ca2+, Mg2+, Na+, K+, etc.) which can be exchanged with inorganic and/or organic polycations [208,213]. The presence of cations create micropores between the layers allowing for the entrance of water [210]. MMT particles are typically plate-shaped with thickness of 1 nm and diameter of 0.2 – 2 µm [214] and their surface is highly hydrophilic [210]. The principal types of MMT clays are named based on the dominant exchangeable cation, for instance, sodium montmorillonite and calcium MMT [209,210].

In many MMT deposits, the MMT clay is found mixed with other compounds such as gypsum, quartz, calcium, and sodium feldspar [(CaAl2Si2O8), (NaAl3Si2O8)] [209,211,213], originating a mineral known as bentonite. To be considered as a bentonite, the percentage of MMT must be greater than 80 % [215]. Depending on the treatment type to modify their structure, bentonites are usually classified into native bentonite, active bentonite (alkaline or acid bentonite), and organic bentonite (presence of organic compounds) [216]. These terms also apply to the mineral MMT.

Considering the excellent physicochemical properties of this kind of clay, such as possessing large specific surface area, high cation exchange capacity, strong adsorptive affinity, low cost, swelling capacity, and low hydraulic conductivity, among others [211,214], MMT or bentonite are suitable materials to combine with LDHs.

The reported LDH/MMT composites synthesis methods are described below:1. Mechanical mixing of both components is the most used method for generating LDH/MMT composites. This method consists of a mixture of LDH and MMT in powder form, dispersed in water and mixed by stirring [217], or adding the MMT in powder to a LDH dispersion [218]. The method presents some variations of the conditions as specified below:1.1. Mixing of both components in the colloidal form and stirring at room temperature [219] or treated with ultrasound [220]. The resulting composites are characterized by a heterogeneous mixing of MMT and LDH particles, this being independent of the treatment used.

1.2. Formation of mixed thin films of LDH and MMT from colloidal suspensions employing glass [221], quartz [222], and polystyrene [223] as supports. Independently of the support used, the LDH/MMT nanocomposites are characterized by a periodic alternation of MMT and LDH nanosheets. This methodology involves evaporation processes to alternate layers of material, as depicted in the Fig. 9 [221].Fig. 9 Schematic illustration of the formation of layered hybrids with periodically alternating positive and negatively charged inorganic sheets. Copyright 2013, reproduced with permission from reference [221].

Fig 9

1.3. Mixing LDH and MMT delaminated dispersions by stirring. In this case, the resulting composite is assembled layer by layer of each component. Their lamellar structures result in a slight difference in terms of thickness and sizes compared to the initial materials [224].

1.4. Ultra-stirring of LDH with MMT dispersions [[225], [226], [227]]. This synthesis procedure promotes the formation of LDH/MMT composites characterized by small round plates of LDH well distributed over the irregular large thin flakes of the MMT.

2. Crystallizing LDH over a dispersion of powder MMT. In this case, the metal salts of LDH precursors and a basic solution are added dropwise to an aqueous dispersion of MMT, with some variations in the treatment conditions as described below:2.1. Crystallizing LDH over MMT dispersion followed by an ultrasound irradiation treatment [228]. This LDH crystallization mode generates a composite with micrometer-sized particles where no interaction between particles were observed.

2.2. Crystallizing LDH over MMT dispersion over stirring without hydrothermal treatment [229,230]. The resulting composite is characterized by a corrugated and scrolled morphology, with the LDH crystals being located on the external surface of MMT clay. This type of morphology exhibits the flower-like structure with spherical agglomerates, as shown in the Fig. 10 [230].Fig. 10 SEM analysis of S2-LDH (a), S2-MMT (b), S3-MMT (c), S4-MMT (d). Copyright 2023, reproduced with permission from reference [230].

Fig 10

2.3. Coprecipitating LDH on colloidal MMT dispersion without a conventional hydrothermal treatment [231]. The resulting composite is composed by the dispersion of LDH flakes on the MMT surface.

2.4. Adding colloidal suspension of MMT (in the form of bentonite) to the LDH precursor salts, followed by a conventional hydrothermal treatment [232]. The generated composite is formed by the combination of bentonite nanoparticles homogeneously embedded in the layers of the LDH material, producing a fluffy nanostructure with higher interparticle porosity.

3. Crystallizing LDH by the urea hydrolysis method over a dispersion of powder MMT. The urea hydrolysis method consists of using a urea solution instead of hydroxides as a precipitating agent. Some modifications on the conditions of this method are presented below:3.1. The LDH is prepared by the urea hydrolysis over a dispersion of powder MMT. In this composite, the LDH compound is adhered to the bentonite surface and pores [233].

3.2. The LDH is prepared by urea hydrolysis on a colloidal MMT. The composite is constituted by homogeneously grafted LDH particles on the MMT surface [234].

The presented LDH/MMT composites can be characterized by being of low cost [233], environment friendly, and having a high adsorption capacity, that makes them useful as adsorbents of phosphates for waste water remediation [226], uranyl ions from natural and polluted waters [229], or to purify waste water from Pb2+, Cu2+, and methyl orange [233]. Other applications of these composites are as antibacterial materials against Escherichia coli [217], in corrosion protection [235], and in CO2/N2 separation [223].

LDH/vermiculite composites

Vermiculite is a naturally abundant clay mineral, an inexpensive hydrous phyllosilicate 2:1 composed of the combination of two silica tetrahedral sheets with an octahedral sheet [236]. Generally, this clay is formed by weathering or hydrothermal alteration of biotite or phlogopite [237]. The vermiculite presents negatively charged layers which are neutralized by cations such as Ca2+ or Mg2+. This clay exhibits high cation-exchange capacity and high charge density, generated by isomorphic substitution of Si4+ by Al3+ [236,238]. The vermiculite´s mainly properties are a large surface area, high rehydration, and exfoliation capabilities, and chemical and mechanical stability. Furthermore it is of relatively low cost, as well as harmless to the environment [237,239,240]. A particularity of this material is an easy delamination process which can be accomplished when it is rapidly heated, generating particles in the form of flakes assembled in an accordion-like mode [239]. According to the vermiculite characteristics and properties, its combination with LDHs to form composites could bring advantages with respect to the original components. The methods to obtain the LDH/vermiculite composites are described below:1. A particular method involves the use of spent liquor from acid treatment of vermiculite that is alkalinized with NaOH solution to form the LDH [241,242]. The obtained products are composed of small crystals of LDH confined into the pores of the partially leached vermiculite, generating a plate-like structure, which is visualized in the Fig. 11.Fig. 11 SEM images of (a) MgAl-LDH; (b) LDH/vermiculite (VMT-LDH); TEM images of (c) MgAl-LDO and (d) VMT-LDO. Copyright 2017, reproduced with permission from reference [242].

Fig 11

2. Impregnation of powder LDH in a vermiculite dispersion [243]. The resulting composites are characterized by uniform sizes of LDH crystals densely located on the surface of the vermiculite component, generating a rough surface and an increased porous structure. Their adsorption capacities are considerably increased.

The composites originating from both methods present high activity as catalysts in the CO methanation [242] or in the adsorption of dyes or heavy metals [241,243].

LDH/halloysite composites

Halloysite is an ecological and biocompatible clay of low cost and high availability that has cation exchange capacity. The most common and interesting type is that of structurally formed aluminosilicate nanotubes (halloysite nano-tubular, HNT) with a chemical formula Al2Si2O5(OH)4∙2H2O. Due to its kind of tubular structure this material presents a high surface area and porosity [244,245] and makes it an excellent material to form composites [246]. The LDH/HNT composites synthesis methods are based on:1. LDHs precursors added over a powder HNT dispersion followed by a conventional hydrothermal treatment [247,248]. The resulting LDH/ HNT composites are composed by nano-sized LDH particles that surround the large nanotubular particles of halloysite, Fig. 12.Fig. 12 SEM microphotographs of the LDH sample (4 upper images) and LDH/HNT (Hall-LDH) material (4 bottom images). The white arrows indicate cross sections of the agglomerates with visible stacking of LDH particles. Copyright 2019, reproduced with permission from reference [247].

Fig 12

2. LDH synthesized by the urea hydrolysis method added on a HNT dispersion [249,250]. In this case, the composite is formed by random particles of HNT embedded within the LDH platelets that looks like a sandwich structure.

3. Mechanical mixing of LDH with HNT. This method generates a composite characterized only by the dispersion of both halloysite and layered double hydroxide particles [247].

The applications of these LDH/HNT composites consist of the adsorption of (Cr2O7)2, (HAsO4)2- and (SO4)2- from waste water [247,248], and as a lysozyme reservoir for pharmacological bactericide material [249].

LDH/kaolinite composites

Kaolinite is a worldwide abundant clay with the chemical formula Al2O3∙2SiO2∙2H2O. Its structure is formed by one alumina octahedral sheet and one silica tetrahedral sheet, classified by a 1:1 type [251,252]. Kaolinite is a natural mineral with a high adsorption capacity [253] being a low cost and environmentally friendly material, thus being a good candidate to combine with the LDH.

The only reported method to combine kaolinite with LDH is by crystallizing LDH from salt precursors on a kaolinite dispersion [[254], [255], [256]]. The resulting composites are formed by loosely packed aggregates of LDH clusters with enlarged inter-particle voids of the kaolinite, producing high porosity, necessary to catalyze the Fischer–Tropsch synthesis [256], or adsorb PO₄³⁻ [254], and (Cr2O7)2- [255].

LDH/sepiolite composites

Sepiolite is a natural fibrous mineral clay with a chemical formula Si6O15Mg4(OH)2∙6H2O [257]. Its structure is composed of blocks of two sheets of tetrahedral silica that are interspersed with an octahedral sheet of magnesium oxide hydroxide corresponding to the 2:1 type clay. The structure is formed by layers in the form of parallel ribbons with interior channels of 0.36 to 1.1 nm [258,259]. This type of structure leads to a material having a high specific surface area and porosity, becoming an interesting material to be used in catalytic or adsorptive processes. They represent an optimal support of the LDH compounds to enhance the LDH surface areas.

Some methods to generate LDH/sepiolite composites consist of:1. Adding LDH salt precursors and basic solutions dropwise together to a sepiolite dispersion, followed by a conventional hydrothermal treatment [260,261]. This generates composites where the LDH particles are located on the sepiolite surface with a good distribution.

2. Reconstructing the LDH structure from the LDH derived mixed oxides present in the surface of a sepiolite. Although this method is efficient in the reconstruction of the LDH structure, it does not favor the assemblage of LDH with the sepiolite, resulting in a rather heterogeneous mixture of the two types of nanoparticles [262].

3. The mixing of both components is done layer by layer sequentially under suction vacuum [263]. This methodology generates a porous structure with a uniform platelet-like morphology corresponding to LDH, while Sepiolite exhibits a rod-like structure, as shown in the Fig. 13.Fig. 13 Scanning electron microscope (SEM) image for LDH-M (a), (a1), M1 (b), (b1) and M2 (c), (c1) of composite membrane surface. Copyright 2019, reproduced with permission from reference [263].

Fig 13

These kind of composites have been used efficiently as catalysts in the photodegradation of methyl orange and methylene blue dyes [261], or in the production of proton conducting membranes [260].

LDH/palygorskite composites

Palygorskite (or attapulgite) is a naturally hydrated magnesium silicate clay mineral with the formula Si8Mg8O20(OH)2(H2O)4·4H2O [264]. It is made up of talc-like tapes of 2:1 phyllosilicate units. Each ribbon is connected to the next by the inversion of SiO4 tetrahedron along a set of Si–O–Si bonds. The rotation of these structural units creates tunnels of 0.64 nm × 0.37 nm [[264], [265], [266]]. In the process of mineralization, some Mg2+ ions in octahedral sites of the palygorskite crystal are substituted by trivalent cations (Al3+ or Fe3+) creating an excess of positive charges [267]. Properties such as a high specific surface area, low cost, natural abundance, nontoxic nature, and environmental friendliness [268] and a special pore structure make the material suitable for combination with LDH. This material is characterized by having a morphology of rod-like crystal bundles and agglomerates, as shown in the Fig. 14 [268].Fig. 14 FESEM images of (a) UAPT, (b) SA(0.01)-APT, (c) SA(0.05)-APT, and (d) SA(0.2)-APT. Copyright 2021, reproduced with permission from reference [268].

Fig 14

Only one synthesis method for this composite has been reported. It consists in adding the LDH precursors salts solutions over a palygorskite dispersion, followed by a conventional hydrothermal treatment [269,270]. This synthesis method leads to the formation of small crystals of LDH located between the fibers of the palygorskite, implying that the spaces between the fibers are partially or completely filled.

The LDH/palygorskite composites have found application as photocatalysts in the discoloration of yellow eosin [269] or as catalysts for ultra-high molecular weight polyethylene [270].

LDH/laponite composites

Laponite is a synthetic clay of smectite type similar to hectorite, characterized by 2:1 layers arrangement in which two tetrahedral silica sheets sandwich one Mg2+containing octahedral sheet [271]. Its chemical formula is Si[Mg5.5Li0.4H4.0O24.0]0.7−Na0.7+. This clay exhibits a characteristic distribution of surface electrical charges that promotes its easy dispersion in water [272]. Due to its favorable physicochemical properties such as high cation exchange property and high specific surface area, laponite constitutes an optimal candidate to combine with LDH.

The only method reported to obtain LDH/laponite composites involves the mixture of mixing microemulsions of both compounds by stirring [[273], [274], [275]]. The obtained composites are characterized by a good intermixture composed of very fine platy particles of LDH crystals with Laponite particles as shown in the Fig. 15 [275]. They have been used as catalysts in the total oxidation of toluene [275] as well as in combustion of VOC with good performance [273,274].Fig. 15 TEM images of (a) CuMnAl-LDH-Laponite-NaOH; (b) CuMnAl-LDH-Laponite-TBAOH; (c) CuMnZrCeAl-LDH-Laponite composites calcined at 600 °C. TBOAH: tetrabutylammonium hydroxide. Copyright 2018, reproduced with permission from reference [275].

Fig 15

LDH/silica composites

Silica (SiO2) is an inactive material that presents a very high specific surface area and tunable porosity, being thermally and chemically stable [121].2.12.1. One synthesis method to obtain this kind of composite is by coprecipitating the precursors of LDH on a SBA-15 material followed by a hydrothermal treatment carried out by microwave irradiation [121]. The resulting composite is characterized by nanolayers of LDH well dispersed on the amorphous silica surface. The SBA-15 support is degraded to amorphous silica during the synthesis reaction of LDH formation. This composite has been used as a Cr (VI) adsorbent.

2.12.2. Adding a LDH dispersion over a microemulsion of SiO2 in a nanodot-coating approach [276]. This composite is formed by uniform SiO2 nanodots attached on the surface of LDH nanoparticles maintaining a hexagonal plate-like morphology. This composite has been employed as methotrexate delivery systems for diagnostic and therapeutic applications.

2.12.3. Coprecipitating the LDH precursor solutions over a silica nanoparticles dispersion, followed by a conventional hydrothermal treatment [[277], [278], [279]]. This method generates composites constituted by SiO2 nanoparticles extended on the LDH lamellar surface, showing a denser dimensional core-shell architecture as shown in Fig. 16 [277]. These composites have been employed as nanocarriers for clinical drugs of topoisomerase inhibitor VP16 [277] or of model DNA based on supercoiled plasmid pEGFP-N2 [278] .Fig. 16 a) TEM images of SiO2, SiO2@LDH, and SiO2@LDH- etoposide. b) Zeta potential distribution for SiO2, SiO2@LDH, SiO2@LDH- etoposide, and etoposide. c) N2 adsorption/desorption isotherms and BJH pore-size distribution curve obtained from the adsorption branch of SiO2, SiO2@LDH, and SiO2@LDH- etoposide. Copyright 2016, reproduced with permission from reference [277].

Fig 16

LDH/alumina composites

Gamma-alumina (γ-Al2O3) is a mineral with a high mechanical strength and surface area [280]. It presents high chemical and physical stability, as well as acid/base characteristics. It has been the most commonly used support for various catalysts in the automotive and petroleum industries [281].1. LDH/γ-alumina composites are generated by coprecipitating LDH from the precursor solutions over a γ-Al2O3 dispersion. The LDH crystallization is promoted by a conventional hydrothermal treatment [282]. In this composite, the LDH component is located on the surface and the pores of the alumina component. This composite has been used as a catalyst in the ultradeep hydrodesulfurization process.

2. Kneading of both materials in dried powder conditions [283]. The resulting composite is characterized by the mixture of both components. It has been employed for H2/CO2 separation [283].

LDH/magnetite composites

Magnetite (Fe3O4) is a natural mineral consisting of a spinel-like structure, its most relevant property being magnetism [284].

Only two synthesis methods have been found describing the LDH/magnetite composites:1. The first method proceeds by coprecipitating LDH over a magnetite suspension, followed by a conventional hydrothermal treatment. The composite is characterized by having a good dispersion of the LDH crystals on the magnetite surface. It has been used as photocatalytic material [285], or as a material of controlled drug delivery of salicylic acid [286], l-Dopa [287], or anti-cancer agents such as doxifluridine [288], and 5-Fluorouracil [289].

2. The other method consists of coprecipitating the magnetite over a LDH dispersion, followed by a conventional hydrothermal treatment. The obtained composite presents a very porous structure composed of particles with rough surface and irregular edges. It has been applied in fluoride adsorption ions for water potabilization [290].

LDH/salts composites

Such composites are formed by the impregnation of some simple or complex salts on the LDH material. The salts used are K2CO3 [291], KF, KI, KNO3 [292], CoFe2O4 [293], and Bi2WO6 [294]. In all composites, the LDH surface is partially covered by nanocrystals of the salts.

These composites have been employed as catalysts for biodiesel production [291,292], as photocatalyst in the degradation of rhodamine B, safranine T, and tetracycline in the presence of visible light [294] and as a methyl orange dye adsorber [293].

Waste management of applied inorganic-LDH compounds

Another important aspect to consider is the management of waste after using LDH. One of the ways to reuse LDH waste is its application as an electrocatalyst in direct methanol fuel cells [295]. Some authors report that LDH nanocages can be regenerated successfully using a solvothermal method when adsorbing anionic organic contaminants onto clay [296]. However, if heavy metals such as arsenic are absorbed, the first step for regeneration involves desorbing them from the clay with alkaline and salt solutions or mixtures of solutions, followed by a second step to regenerate the clay with NaOH [297]. Regarding reuse cycles, some authors demonstrate that after four cycles of reuse, the absorption efficiency of LDH is less than 10 %, whereas when LDH is functionalized with absorbents, the efficiency is more than 80 % [298].

As described, among the many important properties that LDH possess is the ability to regenerate through various pathways such as ion exchange or structure reconstruction. Inorganic-LDH compounds have also been characterized by retaining these characteristics, especially in their application as adsorbent materials. Although high operational efficiency has been achieved in its different applications, it is necessary to take into account the applicability on a larger scale, and the simple and lower cost preparation of LDH composite materials [299]. Furthermore, waste recovery offers a sustainable approach to mitigate the adverse environmental impacts of materials and has been recognized as one of the optimal routes to achieve and implement circular economy strategies [300]. One of the challenging sources of industrial waste is spent adsorbents saturated with various types of contaminants. Therefore, currently there are still some limitations for its reuse after the various cycles of operation and it is necessary to consider the challenge of applying new methods for the regeneration of LDH materials, which should be the motivation for future research to seek advanced modifications, easier to operate and environmentally friendly in the industry.

Finally, when it comes to using materials based on LDH, their final use depends on the final state of the material. If its structure has collapsed, the clay can be used as filler, or its structure can be regenerated through a chemical process. If the structure remains intact, it can be calcined for reuse.

Overview of future LDH-composites

In summary, LDH composites have been applied to construct different promising sorbents and catalysts by incorporating nanoparticles or other substances. LDHs can offer their unique properties and possibly induce new performance. The main advantages of LDHs over conventional anion exchange resins include their higher anion exchange capacity for certain anions and good thermal stability [305].

The research presented focuses on the various methods developed for obtaining composites based on LDH and inorganic materials, considering the way of joining or generating each reviewed material. Since not all the reviewed inorganic materials can be obtained synthetically, their combination could range from a simple physical mixture to a complex synthesis that improves the physicochemical properties of the material, the variation of the available LDH composites and the morphology achieved by the different methods are still limited; therefore, it is worth investigating further the optimization of the synthesis condition for a variety of LDH.

Summary and perspectives

Nowadays, LDH have found applications in many fields, taking advantage of their multiple properties, such as basic character, ion exchange capacity, or enabling the inclusion of oligometals in their compositions. LDH are environmentally friendly, nontoxic, biocompatible, and low-cost multifunctional materials that present a special characteristic where their structures and chemical compositions can be easily designed to a needed application.

If we focus on the industrial aspect, production costs play a very important role. Some authors have reported that the laboratory production process of LDH is estimated at 3.12 USD/g of the produced LDH [301], while the lowest-cost production method is the sol-gel method [302]. However, depending on the required properties, the cost will vary. For instance, if a defined particle size is needed, a crystallization technique such as microwave or ultrasound will be used, which will increase the cost. If a specific element is required in the LDH layers, such as transition elements, the cost will increase significantly. Therefore, depending on the application and LDH design, the final production cost may increase or decrease. Regarding inorganic materials, we find that some materials are generally expensive to produce, such as SBA-15 [303], while others like montmorillonite, natural zeolites, or kaolinite are naturally occurring and therefore, their cost is lower.

Although LDH have an easy and kind structure modification property, their lamellar structure is constituted by big blocks of stacked layers. This kind of arrangement makes the accessibility to the active sites that are locked inside the blocks difficult, leading to materials with low ion exchange capacity or catalytic activity. Thus, the LDH conjugation with inorganic materials can promote the formation of small or nano-LDH crystals, where the active sites turn out to be much more exposed, so facilitating its accessibility and improving their adsorption and catalytic properties. In this sense, LDH have been combined with the most varied types of inorganic compounds, such as zeolites, oxides, or clays, to generate materials with enhanced physico-chemical properties. The LDH/inorganic compounds composites can originate dual basic-acid sites when combined with an acidic component, such as montmorillonite, zeolite, or halloysite, or promote biological activity when combined with iron oxide or silica, as powerful nanosystems for diverse cancer therapies [304].

Thus, the LDH/inorganic compounds composites studied in this paper can offer a wide opportunity to explore, in a deep way, their suitability and benefits for future applications in many different fields in materials science.

Ethics statements

The methods used in the study did not involve any human or animal subjects. No data was used or collected for this work.

CRediT authorship contribution statement

Franchescoli Didier Velázquez-Herrera: Conceptualization, Investigation, Writing – review & editing, Visualization, Supervision. Yohuali Zarazua-Aguilar: Investigation, Writing – original draft. Amanda S. Garzón-Pérez: Investigation, Writing – original draft. Karin Monserrat Álvarez-Gómez: Investigation, Writing – original draft. Geolar Fetter: Writing – review & editing, Visualization, Supervision.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Data availability

No specific data is used.

No data was used for the research described in the article.

Acknowledgments

F.D. Velázquez-Herrera, A.S. Garzón-Pérez and K.M. Álvarez-Gómez greatly acknowledges CONACYT for the fellowships.
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References

1 Reichle W. Synthesis of anionic clay minerals (mixed metal hydroxides, hydrotalcite) Solid State Ionics 22 1986 135 141 10.1016/0167-2738(86)90067-6
2 Zhang Q.-Q. Zhu Y.-J. Wu J. Shao Y.-T. Dong L.-Y. A new kind of filter paper comprising ultralong hydroxyapatite nanowires and double metal oxide nanosheets for high-performance dye separation J. Colloid Interface Sci. 575 2020 78 87 10.1016/j.jcis.2020.04.079 32361048
3 Velázquez-Herrera F.D. Fetter G. Hydrotalcites with heterogeneous anion distributions: a first approach to produce new materials to be used as vehicles for a successive delivery of compounds Clay Miner 55 2020 31 39 10.1180/clm.2020.2
4 Gu Q. Wu Y. Yu S. Organic-inorganic luminescent composites obtained by the intercalation of organic dyes into the layered rare-earth hydroxides Inorganica Chim. Acta. 487 2019 162 168 10.1016/j.ica.2018.12.016
5 Pavlovic M. Rouster P. Oncsik T. Szilagyi I. Tuning colloidal stability of layered double hydroxides: from monovalent ions to polyelectrolytes Chempluschem 82 2017 121 131 10.1002/cplu.201600295 31961513
6 Cavani F. Trifirò F. Vaccari A. Hydrotalcite-type anionic clays: preparation, properties and applications Catal. Today. 11 1991 173 301 10.1016/0920-5861(91)80068-K
7 Sommer A. Romero A. Fetter G. Palomares E. Bosch P. Exploring and tuning the anchorage of chlorophyllin molecules on anionic clays Catal. Today. 212 2013 186 193 10.1016/j.cattod.2013.03.014
8 Palmer S. Frost R. Nguyen T. Hydrotalcites and their role in coordination of anions in Bayer liquors: anion binding in layered double hydroxides Coord. Chem. Rev. 253 2009 250 267 10.1016/j.ccr.2008.01.012
9 Veteška M. Pospíšil M. Melánová K. Beneš L. Zima V. Structure analysis of hydrotalcite intercalated with pyrenetetrasulfonate; experiments and molecular modelling J. Mol. Model. 14 2008 1119 1129 10.1007/s00894-008-0355-3 18682992
10 Sikander U. Sufian S. Salam M.A. A review of hydrotalcite based catalysts for hydrogen production systems Int. J. Hydrogen Energy. 42 2017 19851 19868 10.1016/j.ijhydene.2017.06.089
11 Netzahualcoyotzi I. Galicia V. Rivera J.A. Fetter G. Bosch P. Stabilization of hemoglobin in double layered hydroxides to be used in carbon monoxide bio-oxidation I-synthesis and characterization Catal. Today. 266 2016 212 218 10.1016/j.cattod.2015.11.022
12 Wang Q. O'Hare D. Recent advances in the synthesis and application of layered double hydroxide (LDH) nanosheets Chem. Rev. 112 2012 4124 4155 10.1021/cr200434v 22452296
13 Rodrigues E. Pereira P. Martins T. Vargas F. Scheller T. Correa J. Del Nero J. Moreira S.G.C. Ertel-Ingrisch W. De Campos C.P. Gigler A. Novel rare earth (Ce and La) hydrotalcite like material: synthesis and characterization Mater. Lett. 78 2012 195 198 10.1016/j.matlet.2012.03.025
14 Zarazúa-Aguilar Y. Paredes-Carrera S.P. Valenzuela-Zapata M.A. Sánchez-Ochoa J.C. Cr (VI) and naftalene simultaneous degradation using layered double hydroxides CuZnGa (Degradación simultánea de Cr(VI) y naftaleno empleando compuestos tipo hidrotalcita CuZnGa) Rev. Mex. Ing. Química. 17 2018 679 691 10.24275/uam/izt/dcbi/revmexingquim/2018v17n2/zarazua
15 Wen R. Yang Z. Chen H. Hu Y. Duan J. Zn-Al-La hydrotalcite-like compounds as heating stabilizer in PVC resin J. Rare Earths. 30 2012 895 902 10.1016/S1002-0721(12)60151-3
16 Gräfe M. Bunney K.G. Cumberland S. Douglas G. Mechanisms of uranyl sequestration by hydrotalcite ACS Omega 2 2017 7112 7119 10.1021/acsomega.7b01050 31457291
17 Velu S. Sabde D.P. Shah N. Sivasanker S. New hydrotalcite-like anionic clays containing Zr4+ in the layers: synthesis and physicochemical properties Chem. Mater. 10 1998 3451 3458 10.1021/cm980185x
18 Sharma S.K. Sidhpuria K.B. Jasra R.V. Ruthenium containing hydrotalcite as a heterogeneous catalyst for hydrogenation of benzene to cyclohexane J. Mol. Catal. A Chem. 335 2011 65 70 10.1016/j.molcata.2010.11.015
19 Basile F. Basini L. Fornasari G. Gazzano M. Trifirò F. Vaccari A. New hydrotalcite-type anionic clays containing noble metals Chem. Commun. 1996 2435 2436 10.1039/CC9960002435
20 Zhang J. Xu N. Hydrogen production from ethylene glycol aqueous phase reforming over Ni–Al layered hydrotalcite-derived catalysts Catalysts 10 2020 54 10.3390/catal10010054
21 Velázquez-Herrera F.D. Fetter G. Rosato V. Pereyra A.M. Basaldella E.I. Effect of structure, morphology and chemical composition of Zn-Al, Mg/Zn-Al and Cu/Zn-Al hydrotalcites on their antifungal activity against A. niger J. Environ. Chem. Eng. 6 2018 3376 3383 10.1016/j.jece.2018.04.069
22 Valeikiene L. Paitian R. Grigoraviciute-Puroniene I. Ishikawa K. Kareiva A. Transition metal substitution effects in sol-gel derived Mg3-xMx/Al1 (M = Mn, Co, Ni, Cu, Zn) layered double hydroxides Mater. Chem. Phys. 237 2019 121863 10.1016/j.matchemphys.2019.121863
23 Unnikrishnan R. Narayanan S. Metal containing layered double hydroxides as efficient catalyst precursors for the selective conversion of acetone J. Mol. Catal. A Chem. 144 1999 173 179 10.1016/S1381-1169(98)00355-0
24 Zhang W. Cheng H. Peng S. Li D. Gao H. Wang D. Performance and mechanisms of wastewater sludge conditioning with slag-based hydrotalcite-like minerals (Ca/Mg/Al-LDH) Water Res 169 2020 115265 10.1016/j.watres.2019.115265
25 Pérez Zurita M.J. Bartolini M. Righi T. Vitale G. Pereira Almao P. Hydrotalcite type materials as catalyst precursors for the catalytic steam cracking of toluene Fuel 154 2015 71 79 10.1016/j.fuel.2015.03.002
26 Zhang J. Zhao N. Wei W. Sun Y. Partial oxidation of methane over Ni/Mg/Al/La mixed oxides prepared from layered double hydrotalcites Int. J. Hydrogen Energy. 35 2010 11776 11786 10.1016/j.ijhydene.2010.08.025
27 Rodriguez-Chiang L.M. Llorca J. Dahl O.P. Effect of Fe–Zn–Mg–Al hydrotalcites on the methane potential of synthetic sulfate-containing wastewater J. Water Process Eng. 10 2016 120 127 10.1016/j.jwpe.2016.03.001
28 Velu S. Ramaswamy V. Sivasanker S. New hydrotalcite-like anionic clays containing Zr4+ in the layers Chem. Commun. 1997 2107 2108 10.1039/a704752e
29 Tichit D. Das N. Coq B. Durand R. Preparation of Zr-containing layered double hydroxides and characterization of the acido-basic properties of their mixed oxides Chem. Mater. 14 2002 1530 1538 10.1021/cm011125l
30 Velu S. Suzuki K. Okazaki M. Osaki T. Tomura S. Ohashi F. Synthesis of new Sn-incorporated layered double hydroxides and their thermal evolution to mixed oxides Chem. Mater. 11 1999 2163 2172 10.1021/cm990067p
31 Intissar M. Holler S. Malherbe F. Besse J.-P. Leroux F. Incorporation of Ti4+ into layered double hydroxide sheets? The response by X-ray diffraction and absorption study J. Phys. Chem. Solids. 65 2004 453 457 10.1016/j.jpcs.2003.08.030
32 Serna C.J. Rendon J.L. Iglesias J.E. Crystal-chemical study of layered [Al2Li(OH)6]+X− · nH2O Clays Clay Miner 30 1982 180 184 10.1346/CCMN.1982.0300303
33 Hofmeister W. Von Platen H. Crystal chemistry and atomic order in brucite-related double-layer structures Crystallogr. Rev. 3 1992 3 26 10.1080/08893119208032964
34 Rives V. Layered double hydroxides: present, and future 2001 10.1177/1090820X10380861
35 Mallakpour S. Hatami M. Hussain C.M. Recent innovations in functionalized layered double hydroxides: fabrication, characterization, and industrial applications Adv. Colloid Interface Sci. 283 2020 102216 10.1016/j.cis.2020.102216
36 Balcomb B. Singh M. Singh S. Synthesis and characterization of layered double hydroxides and their potential as nonviral gene delivery vehicles ChemistryOpen 4 2015 137 145 10.1002/open.201402074 25969811
37 Costantino U. Ambrogi V. Nocchetti M. Perioli L. Hydrotalcite-like compounds: versatile layered hosts of molecular anions with biological activity Microporous Mesoporous Mater 107 2008 149 160 10.1016/j.micromeso.2007.02.005
38 Miyata S. Anion-exchange properties of hydrotalcite-like compounds Clays Clay Miner 31 1983 305 311 10.1346/CCMN.1983.0310409
39 Fetter G. Ramos E. Olguin M.T. Bosch P. López T. Bulbulian S. Sorption of131I− by hydrotalcites J. Radioanal. Nucl. Chem. 221 1997 63 66 10.1007/BF02035243
40 Pshinko G.N. Layered double hydroxides as effective adsorbents for U(VI) and toxic heavy metals removal from aqueous media J. Chem. 2013 2013 347178 10.1155/2013/347178
41 Choy J.-H. Kwak S.-Y. Park J.-S. Jeong Y.-J. Portier J. Intercalative nanohybrids of nucleoside monophosphates and DNA in layered metal hydroxide J. Am. Chem. Soc. 121 1999 1399 1400 10.1021/ja981823f
42 Zhang H. Ouyang D. Murthy V. Wong Y. Xu Z. Smith S.C. Hydrotalcite intercalated siRNA: computational characterization of the interlayer environment Pharmaceutics 4 2012 296 313 10.3390/pharmaceutics4020296 24300233
43 Zou N. Plank J. Intercalation of papain enzyme into hydrotalcite type layered double hydroxide J. Phys. Chem. Solids. 73 2012 1127 1130 10.1016/J.JPCS.2012.04.016
44 Theiss F.L. Ayoko G.A. Frost R.L. Synthesis of layered double hydroxides containing Mg2+, Zn2+, Ca2+and Al3+layer cations by co-precipitation methods - A review Appl. Surf. Sci. 383 2016 200 213 10.1016/j.apsusc.2016.04.150
45 Mozammel T. Dumbre D. Selvakannan P. Sadasivuni K.K. Bhargava S.K. Calcined hydrotalcites of varying Mg/Al ratios supported Rh catalysts: highly active mesoporous and stable catalysts toward catalytic partial oxidation of methane Emergent Mater 4 2021 469 481 10.1007/s42247-020-00158-2
46 Kayano M. Ogawa M. Preparation of large platy particles of Co-Al layered double hydroxides Clays Clay Miner 54 2006 382 389 10.1346/CCMN.2006.0540309
47 Benedictto G.P. Sotelo R.M. Dalla Costa B.O. Fetter G. Basaldella E.I. Potassium-containing hydroxylated hydrotalcite as efficient catalyst for the transesterification of sunflower oil J. Mater. Sci. 53 2018 12828 12836 10.1007/s10853-018-2581-0
48 Ramos-Ramírez E. Gutiérrez-Ortega N. Tzompantzi F. Gómez C.M. del Angel G. Herrera-Pérez G. Serafín-Muñoz A.H. Tzompantzi-Flores C. Activated hydrotalcites obtained by coprecipitation as photocatalysts for the degradation of 2,4,6-trichlorophenol Adv. Mater. Sci. Eng. 2018 2018 8267631 10.1155/2018/8267631
49 Ramos-Ramírez E. Gutiérrez-Ortega N.L. Tzompantzi-Morales F. Del Ángel G.A. Martínez-Gómez C. Pabón-Gelves E. Effect of the Mg/Al ratio on activated sol-gel hydrotalcites for photocatalytic degradation of 2,4,6-trichlorophenol Int. J. Photoenergy. 2017 2017 5373482 10.1155/2017/5373482
50 Shekoohi K. Hosseini F.S. Haghighi A.H. Sahrayian A. Synthesis of some Mg/Co-Al type nano hydrotalcites and characterization MethodsX 4 2017 86 94 10.1016/j.mex.2017.01.003 28239563
51 Yan K. Wu G. Jin W. Recent advances in the synthesis of layered, double-hydroxide-based materials and their applications in hydrogen and oxygen evolution Energy Technol 4 2016 354 368 10.1002/ente.201500343
52 Kloprogge J.T. Hickey L. Frost R.L. The effects of synthesis pH and hydrothermal treatment on the formation of zinc aluminum hydrotalcites J. Solid State Chem. 177 2004 4047 4057 10.1016/j.jssc.2004.07.010
53 Wang Q. Tay H.H. Guo Z. Chen L. Liu Y. Chang J. Zhong Z. Luo J. Borgna A. Morphology and composition controllable synthesis of Mg–Al–CO3 hydrotalcites by tuning the synthesis pH and the CO2 capture capacity Appl. Clay Sci. 55 2012 18 26 10.1016/j.clay.2011.07.024
54 Muñoz M. Moreno S. Molina R. Oxidative steam reforming of ethanol (OSRE) over stable NiCo–MgAl catalysts by microwave or sonication assisted coprecipitation Int. J. Hydrogen Energy. 42 2017 12284 12294 10.1016/j.ijhydene.2017.03.090
55 He J. Wei M. Li B. Kang Y. Evans D.G. Duan X. Preparation of layered double hydroxides Duan X. Evans D.G. Layer. Double Hydroxides. Struct. Bond 2006 Springer Berlin Heidelberg Berlin, Heidelberg 89 119 10.1007/430_006
56 Conterosito E. Gianotti V. Palin L. Boccaleri E. Viterbo D. Milanesio M. Facile preparation methods of hydrotalcite layered materials and their structural characterization by combined techniques Inorganica Chim. Acta. 470 2018 36 50 10.1016/j.ica.2017.08.007
57 Othman M.R. Helwani Z. Martunus W.J.N.Fernando Synthetic hydrotalcites from different routes and their application as catalysts and gas adsorbents: a review Appl. Organomet. Chem. 23 2009 335 346 10.1002/aoc.1517
58 Rivera J.A. Fetter G. Bosch P. Microwave power effect on hydrotalcite synthesis Microporous Mesoporous Mater 89 2006 306 314 10.1016/j.micromeso.2005.10.041
59 Fetter G. Hernández F. Maubert A.M. Lara V.H. Bosch P. Microwave irradiation effect on hydrotalcite synthesis J. Porous Mater. 4 1997 27 30 10.1023/A:1009619005529
60 Mokhtar M. Saleh T.S. Ahmed N.S. Al-Thabaiti S.A. Al-Shareef R.A. An eco-friendly N-sulfonylation of amines using stable and reusable Zn–Al–hydrotalcite solid base catalyst under ultrasound irradiation Ultrason. Sonochem. 18 2011 172 176 10.1016/j.ultsonch.2010.05.001 20627793
61 Garzón-Pérez A.S. Paredes-Carrera S.P. Martínez-Gutiérrez H. Cayetano-Castro N. Sánchez-Ochoa J.C. Pérez-Gutiérrez R.M. Efecto de la irradiación combinada de microondas-ultrasonido en la estructura y morfología de compuestos tipo hidrotalcita Al/Mg-CH3COO y su evaluación en la sorción de un colorante reactivo Rev. Mex. Ing. Química. 19 2020 363 375 10.24275/rmiq/Mat567
62 Ay A.N. Zümreoglu-Karan B. Mafra L. A simple mechanochemical route to layered double hydroxides: synthesis of hydrotalcite-like Mg-Al-NO 3 -LDH by manual grinding in a mortar Zeitschrift Für Anorg. Und Allg. Chemie. 635 2009 1470 1475 10.1002/zaac.200801287
63 Molano-Mendoza M. Donneys-Victoria D. Marriaga-Cabrales N. Mueses M.A. Li Puma G. Machuca-Martínez F. Synthesis of Mg-Al layered double hydroxides by electrocoagulation MethodsX 5 2018 915 923 10.1016/j.mex.2018.07.019 30151351
64 Kalali E.N. Wang X. Wang D.-Y. Functionalized layered double hydroxide-based epoxy nanocomposites with improved flame retardancy and mechanical properties J. Mater. Chem. A. 3 2015 6819 6826 10.1039/C5TA00010F
65 Ahmed Ali Ahmed A. Abidin Talib Z. Zobir Hussein M. Abdullah Ahmed Al-Magdashi Y. New DC conductivity spectra of Zn–Al layered double hydroxide (Zn–Al–NO3–LDH) and its calcined product of ZnO phase AIMS Mater. Sci. 4 2017 670 679 10.3934/matersci.2017.3.670
66 Tichit D. Layrac G. Gérardin C. Synthesis of layered double hydroxides through continuous flow processes: a review Chem. Eng. J. 369 2019 302 332 10.1016/J.CEJ.2019.03.057
67 Centi G. Perathoner S. Catalysis by layered materials: a review Microporous Mesoporous Mater 107 2008 3 15 10.1016/j.micromeso.2007.03.011
68 Bankauskaite A. Baltakys K. Mezinskis G. Modified hydrotalcites application as precursors for (Na,K)Mg/Al spinel-type compounds formation J. Therm. Anal. Calorim. 118 2014 711 718 10.1007/s10973-014-3737-z
69 Pavel O.D. Bîrjega R. Che M. Costentin G. Angelescu E. Şerban S. The activity of Mg/Al reconstructed hydrotalcites by “memory effect” in the cyanoethylation reaction Catal. Commun. 9 2008 1974 1978 10.1016/j.catcom.2008.03.027
70 Hosni K. Srasra E. Nitrate adsorption from aqueous solution by MII-Al-CO3 layered double hydroxide Inorg. Mater. 44 2008 742 749 10.1134/S0020168508070121
71 Sani T. Adem M. Fetter G. Bosch P. Diaz I. Defluoridation performance comparison of nano-hydrotalcite/hydroxyapatite composite with calcined hydrotalcite and hydroxyapatite Water. Air. Soil Pollut. 227 2016 1 8 10.1007/s11270-016-2786-2
72 Bergadà O. Vicente I. Salagre P. Cesteros Y. Medina F. Sueiras J.E. Microwave effect during aging on the porosity and basic properties of hydrotalcites Microporous Mesoporous Mater 101 2007 363 373 10.1016/j.micromeso.2006.11.033
73 Zhao S. Yi H. Tang X. Gao F. Yu Q. Zhou Y. Wang J. Huang Y. Yang Z. Enhancement effects of ultrasound assisted in the synthesis of NiAl hydrotalcite for carbonyl sulfide removal Ultrason. Sonochem. 32 2016 336 342 10.1016/j.ultsonch.2016.04.001 27150779
74 Figueredo Benício L.P. Alvarenga Silva R. Aparecida Lopes J. Eulálio D. Menezes dos Santos R.M. Angelo de Aquino L. Vergütz L. Ferreira Novais R. Marciano da Costa L. Garcia Pinto F. Tronto J. Hidróxidos duplos lamelares: nanomateriais para aplicaóes na agricultura Rev. Bras. Cienc. Do Solo. 39 2015 1 13 10.1590/01000683rbcs20150817
75 Lagaly G. Mecking O. Penner D. Colloidal magnesium aluminum hydroxide and heterocoagulation with a clay mineral. I. Properties of colloidal magnesium aluminum hydroxide Colloid Polym. Sci. 279 2001 1090 1096 10.1007/s003960100525
76 Zhang Y. Evans J.R.G. Alignment of layered double hydroxide platelets Colloids Surfaces A Physicochem. Eng. Asp. 408 2012 71 78 10.1016/j.colsurfa.2012.05.033
77 Kim H.-J. Lee G.J. Choi A.-J. Kim T.-H. Kim T. Oh J.-M. Layered double hydroxide nanomaterials encapsulating angelica gigas nakai extract for potential anticancer nanomedicine Front. Pharmacol. 9 2018 10.3389/fphar.2018.00723
78 Fang L. Li W. Chen H. Xiao F. Huang L. Holm P.E. Hansen H.C.B. Wang D. Synergistic effect of humic and fulvic acids on Ni removal by the calcined Mg/Al layered double hydroxide RSC Adv 5 2015 18866 18874 10.1039/C4RA15406A
79 Sriram G. Uthappa U.T. Losic D. Kigga M. Jung H.-Y. Kurkuri M.D. Mg–Al-layered double hydroxide (LDH) modified diatoms for highly efficient removal of congo red from aqueous solution Appl. Sci. 10 2020 2285 10.3390/app10072285
80 Abdel Moaty S.A. Mahmoud R.K. Mohamed N.A. Gaber Y. Farghali A.A. Abdel Wahed M.S.M. Younes H.A. Synthesis and characterisation of LDH-type anionic nanomaterials for the effective removal of doxycycline from aqueous media Water Environ. J. 34 2020 290 308 10.1111/wej.12526
81 Palmer S.J. Frost R.L. Nguyen T. Thermal decomposition of hydrotalcite with molybdate and vanadate anions in the interlayer J. Therm. Anal. Calorim. 92 2008 879 886 10.1007/s10973-007-8642-2
82 Meyer O. Roessner F. Rakoczy R.A. Fischer R.W. Impact of organic interlayer anions in hydrotalcite precursor on the catalytic activity of hydrotalcite-derived mixed oxides ChemCatChem 2 2010 314 321 10.1002/cctc.200900257
83 Xu Z.P. (Max) Lu G.Q. Layered double hydroxide nanomaterials as potential cellular drug delivery agents Pure Appl. Chem. 78 2006 1771 1779 10.1351/pac200678091771
84 Jin W. Lee D. Jeon Y. Park D.-H. Biocompatible hydrotalcite nanohybrids for medical functions Minerals 10 2020 172 10.3390/min10020172
85 Ropp R.C. Group 16 (O, S, Se, Te) alkaline earth compounds Encycl. Alkaline Earth Compd 2013 Elsevier 105 197 10.1016/B978-0-444-59550-8.00003-X
86 Mohamed I.Hafez Minagawa K. Mori T. Tanak M. Versatile nanocomposite formulation system of non-steroidal anti-inflammatory drugs of the arylalkanoic acids Adv. Nanocomposite Technol 2011 InTech 10.5772/21077
87 Géraud E. Prévot V. Ghanbaja J. Leroux F. Macroscopically ordered hydrotalcite-type materials using self-assembled colloidal crystal template Chem. Mater. 18 2006 238 240 10.1021/cm051770i
88 Li Z. Yang B. Zhang S. Wang B. Xue B. A novel approach to hierarchical sphere-like ZnAl-layered double hydroxides and their enhanced adsorption capability J. Mater. Chem. A. 2 2014 10202 10.1039/c4ta01028k
89 Michalik A. Napruszewska B.D. Walczyk A. Kryściak-Czerwenka J. Duraczyńska D. Serwicka E.M. Synthesis of nanocrystalline Mg-Al hydrotalcites in the presence of starch—The effect on structure and composition Materials (Basel) 13 2020 602 10.3390/ma13030602 32013086
90 Segura-Pérez V. Lobo-Sánchez M. Velázquez-Herrera F.D. Frías-Vázquez D.A. Reyes-Cervantes E. Fetter G. Hydrotalcite/hydroxyapatite composites with high bacterial activity against clinical bacteria. A new alternative to prevent osteomyelitis diseases Microporous Mesoporous Mater 298 2020 110069 10.1016/j.micromeso.2020.110069
91 Liotta L.F. Gruttadauria M. Di Carlo G. Perrini G. Librando V. Heterogeneous catalytic degradation of phenolic substrates: catalysts activity J. Hazard. Mater. 162 2009 588 606 10.1016/j.jhazmat.2008.05.115 18586389
92 Chen H. Ding Y. Cong N.T. Dou B. Dupont V. Ghadiri M. Williams P.T. Progress in low temperature hydrogen production with simultaneous CO2 abatement Chem. Eng. Res. Des. 89 2011 1774 1782 10.1016/j.cherd.2010.06.008
93 Torralba-Sánchez R. López-Jurado D. Rivera J.A. Fetter G. Hernández-Huesca R. Pérez-Cruz M.A. Bosch P. High-performance materials based on lithium-containing hydrotalcite-bayerite composites for biogas upgrade Energy and Fuels. 30 2016 7474 7480 10.1021/acs.energyfuels.6b00129
94 Mardones L.E. Legnoverde M.S. Simonetti S. Basaldella E.I. Theoretical and experimental study of isothiazolinone adsorption onto ordered mesoporous silica Appl. Surf. Sci. 389 2016 790 796 10.1016/j.apsusc.2016.07.113
95 Zhang R. Ai Y. Lu Z. Application of multifunctional layered double hydroxides for removing environmental pollutants: recent experimental and theoretical progress J. Environ. Chem. Eng. 8 2020 103908 10.1016/j.jece.2020.103908
96 León-Vallejo A.M. Velázquez-Herrera F.D. Sampieri Á. Landeta-Cortés G. Fetter G. Study of layered double hydroxides as bactericidal materials against Corynebacterium ammoniagenes, a bacterium responsible for producing bad odors from human urine and skin infections Appl. Clay Sci. 180 2019 105194 10.1016/j.clay.2019.105194
97 Lobo-Sánchez M. Nájera-Meléndez G. Luna G. Segura-Pérez V. Rivera J.A. Fetter G. ZnAl layered double hydroxides impregnated with eucalyptus oil as efficient hybrid materials against multi-resistant bacteria Appl. Clay Sci. 153 2018 61 69 10.1016/j.clay.2017.11.017
98 León-Vallejo A.M. Fetter G. Sampieri Á. Rubio-Rosas E. Synthesis of Cotton Fibers Impregnated with Bactericidal Hydrotalcites to be used in Medical Textile Supplies MRS Adv. 1–9 2017 10.1557/adv.2017.598
99 Cruz-Hernández M. Velázquez-Herrera F.D. Giovanela M. da Silva Crespo J. Fetter G. Synthesis of novel hybrid melanin-hydrotalcite with potential lethal activity against microorganisms Mater. Lett. 278 2020 10.1016/j.matlet.2020.128442
100 Wang J. Liu Q. Zhang G. Li Z. Yang P. Jing X. Zhang M. Liu T. Jiang Z. Synthesis, sustained release properties of magnetically functionalized organic–inorganic materials: amoxicillin anions intercalated magnetic layered double hydroxides via calcined precursors at room temperature Solid State Sci. 11 2009 1597 1601 10.1016/j.solidstatesciences.2009.06.015
101 Thakur S. Saini R.V. Singh P. Raizada P. Thakur V.K. Saini A.K. Nanoparticles as an emerging tool to alter the gene expression: preparation and conjugation methods Mater. Today Chem. 17 2020 100295 10.1016/j.mtchem.2020.100295
102 Hu T. Gu Z. Williams G.R. Strimaite M. Zha J. Zhou Z. Zhang X. Tan C. Liang R. Layered double hydroxide-based nanomaterials for biomedical applications Chem. Soc. Rev. 51 2022 6126 6176 10.1039/D2CS00236A 35792076
103 Tang S. Yao Y. Chen T. Kong D. Shen W. Lee H.K. Recent advances in the application of layered double hydroxides in analytical chemistry: a review Anal. Chim. Acta. 1103 2020 32 48 10.1016/j.aca.2019.12.065 32081187
104 Abdallah I.A. Hammad S.F. Bedair A. Abdelhameed R.M. Locatelli M. Mansour F.R. Applications of layered double hydroxides in sample preparation: a review Microchem. J. 192 2023 108916 10.1016/j.microc.2023.108916
105 Zhang Y. Xu H. Lu S. Preparation and application of layered double hydroxide nanosheets RSC Adv. 11 2021 24254 24281 10.1039/D1RA03289E 35479011
106 Pelalak R. Hassani A. Heidari Z. Zhou M. State-of-the-art recent applications of layered double hydroxides (LDHs) material in Fenton-based oxidation processes for water and wastewater treatment Chem. Eng. J. 474 2023 145511 10.1016/j.cej.2023.145511
107 Grover A. Mohiuddin I. Lee J. Brown R.J.C. Malik A.K. Aulakh J.S. Kim K.-H. Progress in pre-treatment and extraction of organic and inorganic pollutants by layered double hydroxide for trace-level analysis Environ. Res. 214 2022 114166 10.1016/j.envres.2022.114166
108 Abd El-Monaem E.M. Elshishini H.M. Bakr S.S. El-Aqapa H.G. Hosny M. Andaluri G. El-Subruiti G.M. Omer A.M. Eltaweil A.S. A comprehensive review on LDH-based catalysts to activate persulfates for the degradation of organic pollutants NPJ Clean Water 6 2023 34 10.1038/s41545-023-00245-x
109 Zdainal Abidin S.N. Lee H.V. Asikin-Mijan N. Juan J.C. Rahman N.A. Mastuli M.S. Taufiq-Yap Y.H. Kong P.S. Ni Zn and Fe hydrotalcite-like catalysts for catalytic biomass compound into green biofuel Pure Appl. Chem. 92 2020 587 600 10.1515/pac-2019-0820
110 Pérez-Verdejo A. Sampieri Á. Pfeiffer H. Ruiz-Reyes M. Santamaría J.-D. Fetter G. Nanoporous composites prepared by a combination of SBA-15 with Mg–Al mixed oxides. Water vapor sorption properties Beilstein J. Nanotechnol. 5 2014 1226 1234 10.3762/bjnano.5.136 25161858
111 Zhao D. Triblock copolymer syntheses of mesoporous silica with periodic 50 to 300 Angstrom pores Science (80-.) 279 1998 548 552 10.1126/science.279.5350.548
112 Izquierdo-Barba I. Sousa E. Doadrio J.C. Doadrio A.L. Pariente J.P. Martínez A. Babonneau F. Vallet-Regí M. Influence of mesoporous structure type on the controlled delivery of drugs: release of ibuprofen from MCM-48, SBA-15 and functionalized SBA-15 J. Sol-Gel Sci. Technol. 50 2009 421 429 10.1007/s10971-009-1932-3
113 Sampieri Á. Pérez-Osorio G. Hernández-Espinosa M.Á. Ruiz-López I.I. Ruiz-Reyes M. Arriola-Morales J. Narváez-Fernández R.I. Sorption of BTEX on a nanoporous composite of SBA-15 and a calcined hydrotalcite Nano Converg. 5 2018 21 10.1186/s40580-018-0153-2 30148042
114 da Silva M.T.P. Villarroel-Rocha J. Toncón-Leal C.F. Barbosa F.F. Miranda M.O. Torres M.A.M. Sapag K. Pergher S.B.C. Braga T.P. Textural and photocatalytic characteristics of iron-cobalt based nanocomposites supported on SBA-15: synergistic effect between Fe2+ and FeO on photoactivity Microporous Mesoporous Mater 310 2021 110582 10.1016/j.micromeso.2020.110582
115 Popova M.D. Szegedi Á. Kolev I.N. Mihály J. Tzankov B.S. Momekov G.T. Lambov N.G. Yoncheva K.P. Carboxylic modified spherical mesoporous silicas s drug delivery carriers Int. J. Pharm. 436 2012 778 785 10.1016/j.ijpharm.2012.07.061 22884833
116 Ji C. Wang Y. Zhao N. Synthesis of Cu Al hydrotalcite-SBA-15 composites and CO2 capture using the sorbent Appl. Surf. Sci. 481 2019 337 343 10.1016/j.apsusc.2019.03.039
117 Sadjadi S. Heravi M.M. Zadsirjan V. Farzaneh V. SBA-15/hydrotalcite nanocomposite as an efficient support for the immobilization of heteropolyacid: a triply-hybrid catalyst for the synthesis of 2-amino-4H-pyrans in water Appl. Surf. Sci. 426 2017 881 889 10.1016/j.apsusc.2017.06.182
118 Prabu M. Manikandan M. Kandasamy P. Kalaivani P.R. Rajendiran N. Raja T. Synthesis of biodiesel using the Mg/Al/Zn hydrotalcite/SBA-15 nanocomposite catalyst ACS Omega 4 2019 3500 3507 10.1021/acsomega.8b02547
119 Zhu G. Zhao Y. Su L. Qiu P. Luo W. Recent advances on the synthesis of mesoporous metals for electrocatalytic methanol oxidation Emergent Mater 3 2020 291 306 10.1007/s42247-020-00082-5
120 Pramod C.V. Upendar K. Mohan V. Sarma D.S. Dhar G.M. Prasad P.S.S. Raju B.D. Rao K.S.R. Hydrotalcite-SBA-15 composite material for efficient carbondioxide capture J. CO2 Util. 12 2015 109 115 10.1016/j.jcou.2015.05.002
121 Pérez E. Ayele L. Getachew G. Fetter G. Bosch P. Mayoral A. Díaz I. Removal of chromium(VI) using nano-hydrotalcite/SiO2 composite J. Environ. Chem. Eng. 3 2015 1555 1561 10.1016/j.jece.2015.05.009
122 Wu K. Ye Q. Wang L. Meng F. Dai H. Polyethyleneimine-modified layered double hydroxide/SBA-15 composites: a novel kind of highly efficient CO2 adsorbents Appl. Clay Sci. 229 2022 106660 10.1016/j.clay.2022.106660
123 Velázquez-Herrera F.D. Sampieri A. Fetter G. LDH as basicity enhancers of new mesoporous nanocomposites MRS Commun 2023 10.1557/s43579-022-00317-y
124 Velázquez-Herrera F.D. Lobo-Sánchez M. Fetter G. LDH/SBA-15 nanocomposite containing nitrogen-fixing bacteria as an efficient biofertilizer Mater. Today Commun. 2022 103832 10.1016/j.mtcomm.2022.103832
125 Velázquez-Herrera F.D. González-Rodal D. Fetter G. Pérez-Mayoral E. Enhanced catalytic performance of highly mesoporous hydrotalcite/SBA-15 composites involved in chromene multicomponent synthesis Microporous Mesoporous Mater 309 2020 110569 10.1016/j.micromeso.2020.110569
126 Baskaran T. Christopher J. Ajithkumar T.G. Sakthivel A. SBA-15 intercalated Mg–Al hydrotalcite: an environmental friendly catalyst for hydroisomerization of olefin Appl. Catal. A Gen. 488 2014 119 127 10.1016/j.apcata.2014.09.024
127 Tao Y.F. Lin W.G. Gao L. Yang J. Zhou Y. Yang J.Y. Wei F. Wang Y. Zhu J.H. Low-cost and effective phenol and basic dyes trapper derived from the porous silica coated with hydrotalcite gel J. Colloid Interface Sci. 358 2011 554 561 10.1016/j.jcis.2011.02.070 21458822
128 Shi L.Y. Ji A. Gao L. Wang Y. Direct Synthesis of Water-Resistant Basic Mesoporous Material HT/SBA-15 2005 Elsevier 10.1016/S0167-2991(05)80384-2
129 Manikandan M. Sangeetha P. Facile synthesis of nanoarchitectured hydrotalcite/SBA-15 composites for the efficient conversion of levulinic acid to ethyl levulinate Silicon 14 2022 3119 3124 10.1007/s12633-021-01076-6
130 Peng J. Iruretagoyena D. Chadwick D. Hydrotalcite/SBA15 composites for pre-combustion CO2 capture: CO2 adsorption characteristics J. CO2 Util. 24 2018 73 80 10.1016/j.jcou.2017.12.004
131 Martínez C. Corma A. Zeolites Compr. Inorg. Chem. II 2013 Elsevier 103 131 10.1016/B978-0-08-097774-4.00506-4
132 Busca G. Zeolites and other structurally microporous solids as acid–base materials Heterog. Catal. Mater. 2014 197 249 10.1016/B978-0-444-59524-9.00007-9
133 Villarroel-Rocha J. Barrera D. Arroyo-Gómez J.J. Sapag K. Critical overview of textural characterization of zeolites by gas adsorption Eds. Valencia S. Rey F. New Dev. Adsorpt. Small Mol. By Zeolites 2020 Springer Cham 31 55 10.1007/430_2020_69
134 Dyer A. Zeolites Encycl. Mater. Sci. Technol 2001 Elsevier 9859 9863 10.1016/B0-08-043152-6/01784-8
135 Gonzalez M.R. Pereyra A.M. Bosch P. Fetter G. Lara V.H. Basaldella E.I. Structural and morphological evolutions of spent FCC catalyst pellets toward NaA zeolite J. Mater. Sci. 51 2016 5061 5072 10.1007/s10853-016-9809-7
136 Kawai T. Tsutsumi K. Evaluation of hydrophilic-hydrophobic character of zeolites by measurements of their immersional heats in water Colloid Polym. Sci. 270 1992 711 715 10.1007/BF00654048
137 Jiang J. Li G. Liu H. Ding Q. Mai K. Preparation and β-crystallization of zeolite filled isotactic polypropylene composites Compos. Part A Appl. Sci. Manuf. 45 2013 88 94 10.1016/j.compositesa.2012.10.002
138 Qu H. Ma Y. Li B. Wang L. Hierarchical zeolites: synthesis, structural control, and catalytic applications Emergent Mater 3 2020 225 245 10.1007/s42247-020-00088-z
139 Zhang F. Lu B. Sun P. Highly stable Ni-based catalysts derived from LDHs supported on zeolite for CO2 methanation Int. J. Hydrogen Energy. 45 2020 16183 16192 10.1016/j.ijhydene.2020.04.099
140 Megías-Sayago C. Bingre R. Huang L. Lutzweiler G. Wang Q. Louis B. CO2 adsorption capacities in zeolites and layered double hydroxide materials Front. Chem. 7 2019 10.3389/fchem.2019.00551
141 Lin Y. Dong X. Zhao L. Hollow N-ZIFs@NiCo-LDH as highly efficient catalysts for 4-nitrophenol and dyes Appl. Organomet. Chem. 34 2020 10.1002/aoc.5814
142 Xie X. Cheng S. Chang Y. Liao J. Synthesis of NiAl-HTLcs/ZSM-5 composite and its application in benzoin ethyl ether reaction Integr. Ferroelectr. 129 2011 18 24 10.1080/10584587.2011.576894
143 Bai Q. Gao L. Sun J. Xu W. Wei R. Xiao G. Cyanobacteria pyrolysis with methanol catalyzed by Mg-Al hydrotalcite-derived oxides/ZSM-5, Energy Sources, Part A Recover Util. Environ. Eff. 40 2018 1273 1278 10.1080/15567036.2018.1476930
144 Gao L. Sun J. Xu W. Xiao G. Catalytic pyrolysis of natural algae over Mg-Al layered double oxides/ZSM-5 (MgAl-LDO/ZSM-5) for producing bio-oil with low nitrogen content Bioresour. Technol. 225 2017 293 298 10.1016/j.biortech.2016.11.077 27898320
145 Zhu B. Wang L. Li G. Jin Q. Composites of layered double hydroxides and ANA-type zeolite synthesized from hazardous secondary aluminum dross for cationic dye wastewater treatment Processes 11 2023 1002 10.3390/pr11041002
146 Subsadsana M. Miyake K. Ono K. Ota M. Hirota Y. Nishiyama N. Sansuk S. Bifunctional ZSM-5/hydrotalcite composite for enhanced production of 5-hydroxymethylfurfural from glucose New J. Chem. 43 2019 9483 9490 10.1039/C9NJ00462A
147 Belviso C. Piancastelli A. Sturini M. Belviso S. Synthesis of composite zeolite-layered double hydroxides using ultrasonic neutralized red mud Microporous Mesoporous Mater 299 2020 110108 10.1016/j.micromeso.2020.110108
148 da Silva L.N. dos S. Moraes D. Santos S.C.A. Corrêa J.A.M. Joint synthesis of Zeolite A-LDH from mineral industry waste Appl. Clay Sci. 161 2018 163 168 10.1016/j.clay.2018.04.018
149 Wang B. Wang D. Guan Y. Xu H. Zhang L. Wu P. Nickel/USY catalyst derived from a layered double hydroxide/zeolite hybrid structure with a high hydrogenation efficiency ChemCatChem 9 2017 4552 4561 10.1002/cctc.201701054
150 Wang B. Zhang J. Ding Y. Peng H. Xu H. Guan Y. Wu H. Wu P. Freestanding Cobalt-Aluminum oxides on USY zeolite as an efficient catalyst for selective catalytic reduction of NO x ChemCatChem 10 2018 4074 4083 10.1002/cctc.201800779
151 Muriithi G.N. Petrik L.F. Doucet F.J. Synthesis, characterisation and CO2 adsorption potential of NaA and NaX zeolites and hydrotalcite obtained from the same coal fly ash J. CO2 Util. 36 2020 220 230 10.1016/j.jcou.2019.11.016
152 Bezerra B. Bieseki L. da Silva D. Pergher S. Development of a zeolite A/LDH composite for simultaneous cation and anion removal Materials (Basel) 12 2019 661 10.3390/ma12040661 30813262
153 Lee J.H. Nam H.J. Rhee S.W. Jung D.-Y. Hybrid assembly of layered double hydroxide nanocrystals with inorganic, polymeric and biomaterials from micro- to nanometer scales Eur. J. Inorg. Chem. 2008 2008 5573 5578 10.1002/ejic.200800668
154 Othman M.R. Rasid N.M. Fernando W.J.N. Mg–Al hydrotalcite coating on zeolites for improved carbon dioxide adsorption Chem. Eng. Sci. 61 2006 1555 1560 10.1016/j.ces.2005.09.011
155 Mokhtar M. Alzhrani G. Aazam E.S. Saleh T.S. Al-Faifi S. Panja S. Maiti D. Synergistic effect of NiLDH@YZ hybrid and mechanochemical agitation on Glaser Homocoupling reaction Chem. – A Eur. J. 2021 10.1002/chem.202100018 chem.202100018
156 Li R. Xue T. Bingre R. Gao Y. Louis B. Wang Q. Microporous Zeolite@Vertically aligned Mg–Al layered double hydroxide Core@Shell structures with improved hydrophobicity and toluene adsorption capacity under wet conditions ACS Appl. Mater. Interfaces. 10 2018 34834 34839 10.1021/acsami.8b15118 30277743
157 Agbeboh N.I. Oladele I.O. Daramola O.O. Adediran A.A. Olasukanmi O.O. Tanimola M.O. Environmentally sustainable processes for the synthesis of hydroxyapatite Heliyon 6 2020 e03765 10.1016/j.heliyon.2020.e03765 32368642
158 Fihri A. Len C. Varma R.S. Solhy A. Hydroxyapatite: a review of syntheses, structure and applications in heterogeneous catalysis Coord. Chem. Rev. 347 2017 48 76 10.1016/j.ccr.2017.06.009
159 Ibrahim M. Labaki M. Giraudon J.-M. Lamonier J.-F. Hydroxyapatite, a multifunctional material for air, water and soil pollution control: a review J. Hazard. Mater. 383 2020 121139 10.1016/j.jhazmat.2019.121139
160 Watanabe Y. Ikoma T. Yamada H. Stevens G.W. Moriyoshi Y. Tanaka J. Komatsu Y. Formation of hydroxyapatite nanocrystals on the surface of Ca-Al-layered double hydroxide J. Am. Ceram. Soc. 93 2010 1195 1200 10.1111/j.1551-2916.2010.03576.x
161 Varadavenkatesan T. Vinayagam R. Pai S. Kathirvel B. Pugazhendhi A. Selvaraj R. Synthesis, biological and environmental applications of hydroxyapatite and its composites with organic and inorganic coatings Prog. Org. Coatings. 151 2021 106056 10.1016/j.porgcoat.2020.106056
162 Vahdat A. Ghasemi B. Yousefpour M. Mechanical properties of the hydroxyapatite and magnetic nanocomposite of hydroxyapatite adsorbents South Afri. J. Chem. Eng. 33 2020 90 94 10.1016/j.sajce.2020.05.007
163 Pai S. Kini S.M. Selvaraj R. Pugazhendhi A. A review on the synthesis of hydroxyapatite, its composites and adsorptive removal of pollutants from wastewater J. Water Process Eng. 38 2020 101574 10.1016/j.jwpe.2020.101574
164 Rodrigues E. Almeida O. Brasil H. Moraes D. dos Reis M.A.L. Adsorption of chromium (VI) on hydrotalcite-hydroxyapatite material doped with carbon nanotubes: equilibrium, kinetic and thermodynamic study Appl. Clay Sci. 172 2019 57 64 10.1016/j.clay.2019.02.018
165 Szcześ A. Hołysz L. Chibowski E. Synthesis of hydroxyapatite for biomedical applications Adv. Colloid Interface Sci. 249 2017 321 330 10.1016/j.cis.2017.04.007 28457501
166 Velázquez-Herrera F.D. González-Rodal D. Fetter G. Pérez-Mayoral E. Towards highly efficient hydrotalcite/hydroxyapatite composites as novel catalysts involved in eco-synthesis of chromene derivatives Appl. Clay Sci. 198 2020 10.1016/j.clay.2020.105833
167 Rivera J.A. Fetter G. Baños L. Guzmán J. Bosch P. New hydroxyapatite-hydrotalcite composites I. synthesis J. Porous Mater. 16 2009 401 408 10.1007/s10934-008-9227-6
168 Guo Y. Gong Z. Li C. Gao B. Li P. Wang X. Zhang B. Li X. Efficient removal of uranium (VI) by 3D hierarchical Mg/Fe-LDH supported nanoscale hydroxyapatite: a synthetic experimental and mechanism studies Chem. Eng. J. 392 2020 123682 10.1016/j.cej.2019.123682
169 Rodrigues E. Brasil H. Barros T. Pereira C. dos Reis M.A.L. Almeida O. Síntese e caracterização do material hidrotalcita-hidroxiapatita dopado com nanotubos de carbono e sua aplicação na catálise da reação de transesterificação Cerâmica 64 2018 166 175 10.1590/0366-69132018643702230
170 Brasil H. Pereira P. Corrêa J. Nascimento L. Preparation of hydrotalcite – hydroxyapatite material and its catalytic activity for transesterification of soybean oil Catal. Letters. 147 2017 391 399 10.1007/s10562-016-1961-9
171 Vilas-Bôas R.N. da Silva L.L.C. Fernandes L.D. Augusto B.L. Mendes M.F. Study of the use of hydrotalcite–hydroxyapatite as heterogeneous catalysts for application in biodiesel using by-product as raw material Catal. Letters. 150 2020 3642 3652 10.1007/s10562-020-03274-0
172 Karami Z. Ganjali M.R. Zarghami Dehaghani M. Aghazadeh M. Jouyandeh M. Esmaeili A. Habibzadeh S. Mohaddespour A. Inamuddin K.Formela Haponiuk J.T. Saeb M.R. Kinetics of cross-linking reaction of epoxy resin with hydroxyapatite-functionalized layered double hydroxides Polymers (Basel) 12 2020 1157 10.3390/polym12051157 32443636
173 Rezvani Z. Akbari M. Surface modification of hydroxyapatite crystals by Mg–Al–CO 3 -layered double hydroxides in HA/Mg–Al–CO 3 –LDH nanocomposite New J. Chem. 39 2015 5189 5196 10.1039/c5nj00664c
174 Tsuji H. Fujii S. Phosphate recovery by generating hydroxyapatite via reaction of calcium eluted from layered double hydroxides Appl. Clay Sci. 99 2014 261 265 10.1016/j.clay.2014.07.003
175 Li S. Bai H. Wang J. Jing X. Liu Q. Zhang M. Chen R. Liu L. Jiao C. In situ grown of nano-hydroxyapatite on magnetic CaAl-layered double hydroxides and its application in uranium removal Chem. Eng. J. 193–194 2012 372 380 10.1016/j.cej.2012.04.025
176 Zhuge Y. Fan G. Lin Y. Yang L. Li F. A hybrid composite of hydroxyapatite and Ca–Al layered double hydroxide supported Au nanoparticles for highly efficient base-free aerobic oxidation of glucose Dalt. Trans. 48 2019 9161 9172 10.1039/C9DT00985J
177 Rivera J.A. Fetter G. Bosch P. New hydroxyapatite – hydrotalcite composites II. microwave irradiation effect on structure and texture J. Porous Mater. 16 2009 409 418 10.1007/s10934-008-9213-z
178 Brasil H. Pereira P. Corrêa J. Nascimento L. Rumjanek V. Almeida V. Coral N. Rodrigues E. Preparation of hydrotalcite–hydroxyapatite material and its catalytic activity for transesterification of soybean oil Catal. Letters. 147 2017 391 399 10.1007/s10562-016-1961-9
179 Wang X. Ning X. Shao Q. Ge S. Fei Z. Lei J. Hou B. ZnFeAl-layered double hydroxides/TiO2 composites as photoanodes for photocathodic protection of 304 stainless steel Sci. Rep. 8 2018 4116 10.1038/s41598-018-22572-7 29515181
180 Alvarez K.M. Alvarado J. Soto B.S. Hernandez M.A. Synthesis of TiO2 nanoparticles and TiO2-Zeolite composites and study of optical properties and structural characterization Optik (Stuttg) 169 2018 137 146 10.1016/j.ijleo.2018.05.028
181 de Almeida M.F. Bellato C.R. Miranda L.D.L. Milagres J.L. Preparation of calcined hydrotalcite/TiO2-Ag composite and enhanced photocatalytic properties Ceram. Int. 43 2017 1843 1852 10.1016/j.ceramint.2016.10.143
182 de Almeida M.F. Bellato C.R. Mounteer A.H. Ferreira S.O. Milagres J.L. Miranda L.D.L. Enhanced photocatalytic activity of TiO2-impregnated with MgZnAl mixed oxides obtained from layered double hydroxides for phenol degradation Appl. Surf. Sci. 357 2015 1765 1775 10.1016/j.apsusc.2015.10.009
183 Carja G. Nakajima A. Dranca S. Dranca C. Okada K. TiO2/ZnLDH as a self-assembled nanocomposite with photoresponsive properties J. Phys. Chem. C. 114 2010 14722 14728 10.1021/jp103210m
184 Miranda L.D.L. Bellato C.R. Milagres J.L. Moura L.G. Mounteer A.H. de Almeida M.F. Hydrotalcite-TiO2 magnetic iron oxide intercalated with the anionic surfactant dodecylsulfate in the photocatalytic degradation of methylene blue dye J. Environ. Manage. 156 2015 225 235 10.1016/j.jenvman.2015.03.051 25846003
185 Mourid E.H. El Mouchtari E.M. El Mersly L. Benaziz L. Rafqah S. Lakraimi M. Development of a new recyclable nanocomoposite LDH-TiO2 for the degradation of antibiotic sulfamethoxazole under UVA radiation: an approach towards sunlight J. Photochem. Photobiol. A Chem. 396 2020 112530 10.1016/j.jphotochem.2020.112530
186 Arcanjo G.S. Mounteer A.H. Bellato C.R. da Silva L.M.M. Brant Dias S.H. da Silva P.R. Heterogeneous photocatalysis using TiO2 modified with hydrotalcite and iron oxide under UV–visible irradiation for color and toxicity reduction in secondary textile mill effluent J. Environ. Manage. 211 2018 154 163 10.1016/j.jenvman.2018.01.033 29408063
187 Aoudjit F. Cherifi O. Halliche D. Simultaneously efficient adsorption and photocatalytic degradation of sodium dodecyl sulfate surfactant by one-pot synthesized TiO 2 /layered double hydroxide materials Sep. Sci. Technol. 54 2019 1095 1105 10.1080/01496395.2018.1527352
188 Bouberka Z. Benabbou K.A. Khenifi A. Maschke U. Degradation by irradiation of an Acid Orange 7 on colloidal TiO2/(LDHs) J. Photochem. Photobiol. A Chem. 275 2014 21 29 10.1016/j.jphotochem.2013.10.010
189 Lu R. Xu X. Chang J. Zhu Y. Xu S. Zhang F. Improvement of photocatalytic activity of TiO2 nanoparticles on selectively reconstructed layered double hydroxide Appl. Catal. B Environ. 111–112 2012 389 396 10.1016/j.apcatb.2011.10.022
190 Ma C. Wang F. Zhang C. Yu Z. Wei J. Yang Z. Li Y. Li Z. Zhu M. Shen L. Zeng G. Photocatalytic decomposition of Congo red under visible light irradiation using MgZnCr-TiO2 layered double hydroxide Chemosphere 168 2017 80 90 10.1016/j.chemosphere.2016.10.063 27776241
191 Benalioua B. Mansour M. Bentouami A. Boury B. Elandaloussi E.H. The layered double hydroxide route to Bi–Zn co-doped TiO2 with high photocatalytic activity under visible light J. Hazard. Mater. 288 2015 158 167 10.1016/j.jhazmat.2015.02.013 25699677
192 Huang Z. Wu P. Lu Y. Wang X. Zhu N. Dang Z. Enhancement of photocatalytic degradation of dimethyl phthalate with nano-TiO2 immobilized onto hydrophobic layered double hydroxides: a mechanism study J. Hazard. Mater. 246–247 2013 70 78 10.1016/j.jhazmat.2012.12.016
193 Korošec R.C. Miljević B. Umek P. van der Bergh J.M. Vučetić S. Ranogajec J. Photocatalytic self-cleaning properties of Mo:tiO2 loaded Zn–Al layered double hydroxide synthesised at optimised pH value for the application on mineral substrates Ceram. Int. 46 2020 6756 6766 10.1016/j.ceramint.2019.11.166
194 Chong R. Su C. Wang Z. Chang Z. Zhang L. Li D. Enhanced photocatalytic reduction of CO2 on rutile TiO2/MgAl layered double oxides with H2O under ambient temperature Catal. Letters. 150 2020 1061 1071 10.1007/s10562-019-02991-5
195 Hadnadjev-Kostic M. Vulic T. Marinkovic-Neducin R. Lončarević D. Dostanić J. Markov S. Jovanović D. Photo-induced properties of photocatalysts: a study on the modified structural, optical and textural properties of TiO 2 –ZnAl layered double hydroxide based materials J. Clean. Prod. 164 2017 1 18 10.1016/j.jclepro.2017.06.091
196 Yang Y. Yan L. Li J. Li J. Yan T. Sun M. Pei Z. Synergistic adsorption and photocatalytic reduction of Cr(VI) using Zn-Al-layered double hydroxide and TiO2 composites Appl. Surf. Sci. 492 2019 487 496 10.1016/j.apsusc.2019.06.229
197 Chong R. Su C. Du Y. Fan Y. Ling Z. Chang Z. Li D. Insights into the role of MgAl layered double oxides interlayer in Pt/TiO2 toward photocatalytic CO2 reduction J. Catal. 363 2018 92 101 10.1016/j.jcat.2018.04.020
198 Foruzin L.J. Rezvani Z. Nejati K. TiO2@NiAl-Layered double oxide nanocomposite: an excellent photoanode for a dye sensitized solar cell Sol. Energy. 186 2019 106 112 10.1016/j.solener.2019.05.005
199 Seftel E.M. Niarchos M. Vordos N. Nolan J.W. Mertens M. Mitropoulos A.C. Vansant E.F. Cool P. LDH and TiO2/LDH-type nanocomposite systems: a systematic study on structural characteristics Microporous Mesoporous Mater 203 2015 208 215 10.1016/j.micromeso.2014.10.029
200 Aissani A. Kameche M. Benabbou K. Synthesis and characterization of TiO 2 /LDH layered double hydroxide composites: utilization as photocatalysts for amoxicillin degradation under UVA irradiation, Inorg Nano-Metal Chem. 52 2022 1197 1207 10.1080/24701556.2022.2068582
201 Todorova N. Giannakopoulou T. Karapati S. Petridis D. Vaimakis T. Trapalis C. Composite TiO2/clays materials for photocatalytic NOx oxidation Appl. Surf. Sci. 319 2014 113 120 10.1016/j.apsusc.2014.07.020
202 Wang L. Gao X. Cheng Y. Zhang X. Wang G. Zhang Q. Su J. TiO2@MgAl-layered double hydroxide with enhanced photocatalytic activity towards degradation of gaseous toluene J. Photochem. Photobiol. A Chem. 369 2019 44 53 10.1016/j.jphotochem.2018.10.004
203 Seftel E.M. Mertens M. Cool P. The influence of the Ti4+ location on the formation of self-assembled nanocomposite systems based on TiO2 and Mg/Al-LDHs with photocatalytic properties Appl. Catal. B Environ. 134–135 2013 274 285 10.1016/j.apcatb.2013.01.032
204 Paredes S.P. Valenzuela M.A. Fetter G. Flores S.O. TiO2/MgAl layered double hydroxides mechanical mixtures as efficient photocatalysts in phenol degradation J. Phys. Chem. Solids. 72 2011 914 919 10.1016/j.jpcs.2011.03.017
205 Song Z. Gao H. Zhang W. Wang D. Reinforce of hydrotalcite-like loaded TiO2 composite material prepared by Ti-bearing blast furnace slag for photo-degradation of tetracycline J. Water Process Eng. 36 2020 101399 10.1016/j.jwpe.2020.101399
206 Contreras-Ruiz J.C. Martínez-Gallegos M.S. Ordoñez-Regil E. Surface fractal dimension of composites TiO2-hydrotalcite Mater. Charact. 121 2016 17 22 10.1016/j.matchar.2016.09.032
207 Zhao H. Xu J. Liu L. Rao G. Zhao C. Li Y. CO2 photoreduction with water vapor by Ti-embedded MgAl layered double hydroxides J. CO2 Util. 15 2016 15 23 10.1016/j.jcou.2016.04.004
208 Askalany A.A. Ernst S.-J. Hügenell P.P.C. Bart H.-J. Henninger S.K. Alsaman A.S. High potential of employing bentonite in adsorption cooling systems driven by low grade heat source temperatures Energy 141 2017 782 791 10.1016/j.energy.2017.07.171
209 Afolabi R.O. Orodu O.D. Efeovbokhan V.E. Properties and application of Nigerian bentonite clay deposits for drilling mud formulation: recent advances and future prospects Appl. Clay Sci. 143 2017 39 49 10.1016/j.clay.2017.03.009
210 Nones J. Riella H.G. Trentin A.G. Nones J. Effects of bentonite on different cell types: a brief review Appl. Clay Sci. 105–106 2015 225 230 10.1016/j.clay.2014.12.036
211 Wang J. Chen Z. Shao D. Li Y. Xu Z. Cheng C. Asiri A.M. Marwani H.M. Hu S. Adsorption of U(VI) on bentonite in simulation environmental conditions J. Mol. Liq. 242 2017 678 684 10.1016/j.molliq.2017.07.048
212 Shunmugasamy V.C. Xiang C. Gupta N. Clay/polymer nanocomposites: processing, properties, and applications Hybrid Hierarchical Compos. Mater 2015 Springer International Publishing Cham 161 200 10.1007/978-3-319-12868-9_5
213 Magzoub M.I. Nasser M.S. Hussein I.A. Benamor A. Onaizi S.A. Sultan A.S. Mahmoud M.A. Effects of sodium carbonate addition, heat and agitation on swelling and rheological behavior of Ca-bentonite colloidal dispersions Appl. Clay Sci. 147 2017 176 183 10.1016/j.clay.2017.07.032
214 Jayrajsinh S. Shankar G. Agrawal Y.K. Bakre L. Montmorillonite nanoclay as a multifaceted drug-delivery carrier: a review J. Drug Deliv. Sci. Technol. 39 2017 200 209 10.1016/j.jddst.2017.03.023
215 Christidis G.E. Huff W.D. Geological aspects and genesis of bentonites Elements 5 2009 93 98 10.2113/gselements.5.2.93
216 Huang Y. Zhang M. Zou H. Li X. Xing M. Fang X. He J. Genetic damage and lipid peroxidation in workers occupationally exposed to organic bentonite particles Mutat. Res. Toxicol. Environ. Mutagen. 751 2013 40 44 10.1016/j.mrgentox.2012.10.006
217 Deák Á. Janovák L. Tallósy S.P. Bitó T. Sebők D. Buzás N. Pálinkó I. Dékány I. Spherical LDH–Ag°-montmorillonite heterocoagulated system with a pH-dependent sol–gel structure for controlled accessibility of AgNPs immobilized on the clay lamellae Langmuir 31 2015 2019 2027 10.1021/la504096t 25619227
218 Chuaicham C. Xiong Y. Sekar K. Chen W. Zhang L. Ohtani B. Dabo I. Sasaki K. A promising Zn-Ti layered double hydroxide/Fe-bearing montmorillonite composite as an efficient photocatalyst for Cr(VI) reduction: insight into the role of Fe impurity in montmorillonite Appl. Surf. Sci. 546 2021 148835 10.1016/j.apsusc.2020.148835
219 Jia C. Li S. Zong H. Influence of montmorillonite's concentration on the thixotropy of hydrotalcite-like compounds/montmorillonite suspensions Chinese J. Chem. 28 2010 1844 1848 10.1002/cjoc.201090308
220 Mishra M. Bora J.J. Goswamee R.L. Improvement of the mechanical strength of alumina preforms by coating with montmorillonite/LDH gels Appl. Clay Sci. 53 2011 8 14 10.1016/j.clay.2011.04.004
221 Chalasani R. Gupta A. Vasudevan S. Engineering new layered solids from exfoliated inorganics: a periodically alternating hydrotalcite – montmorillonite layered hybrid Sci. Rep. 3 2013 3498 10.1038/srep03498 24336682
222 Huang S. Cen X. Peng H. Guo S. Wang W. Liu T. Heterogeneous ultrathin films of poly(vinyl alcohol)/layered double hydroxide and montmorillonite nanosheets via layer-by-layer assembly J. Phys. Chem. B. 113 2009 15225 15230 10.1021/jp907784k 19860414
223 Zhang Y. Wang H. Zhang Y. Ding X. Liu J. Thin film composite membranes functionalized with montmorillonite and hydrotalcite nanosheets for CO2/N2 separation Sep. Purif. Technol. 189 2017 128 137 10.1016/j.seppur.2017.07.078
224 He S.-H. Pu M. Zhang X.-F. Wang C.-X. Wang H.-X. Analysis and simulations on the structure of sulfanilic acid zwitterion intercalated hydrotalcite and montmorillonite RSC Adv 6 2016 83656 83662 10.1039/C6RA13206E
225 Bakr A.A. Sayed N.A. Salama T.M. Ali I.O. Abdel Gayed R.R. Negm N.A. Kinetics and thermodynamics of Mn(II) removal from aqueous solutions onto Mg-Zn-Al LDH/montmorillonite nanocomposite Egypt. J. Pet. 27 2018 1215 1220 10.1016/j.ejpe.2018.05.003
226 Wang Y. Li G. Adsorption behavior of phosphate on Mg–Al layered double hydroxide/montmorillonite composite Desalin. Water Treat. 57 2016 17963 17972 10.1080/19443994.2015.1088803
227 Bakr A.A. Sayed N.A. Salama T.M. Ali I.O. Gayed R.R.A. Negm N.A. Potential of Mg–Zn–Al layered double hydroxide (LDH)/montmorillonite nanocomposite in remediation of wastewater containing manganese ions Res. Chem. Intermed. 44 2018 389 405 10.1007/s11164-017-3110-5
228 Li C. Zhang J. Lin Y. Chen Y. Xie X. Wang H. Wang L. In situ growth of layered double hydroxide on disordered platelets of montmorillonite Appl. Clay Sci. 119 2016 103 108 10.1016/j.clay.2015.06.032
229 Seddighi H. Khodadadi Darban A. Khanchi A. Fasihi J. Koleini J. LDH(Mg/Al:2)@montmorillonite nanocomposite as a novel anion-exchanger to adsorb uranyl ion from carbonate-containing solutions J. Radioanal. Nucl. Chem. 314 2017 415 427 10.1007/s10967-017-5387-7
230 Waheed T. Min P. ud Din S. Ahmad P. Khandaker M.U. Haq S. Al-Mugren K.S. Rehman F.U. Akram B. Nazir S. Montmorillonite modified Ni/Mg/Al ternary layered double hydroxide nanoflowers with enhanced adsorption features Heliyon 9 2023 e20976 10.1016/j.heliyon.2023.e20976 37886752
231 Wang H. Huang W. Yang L. Preparation and flame retardancy of hydrotalcite/montmorillonite nanocomposite J. Phys. Conf. Ser. 1676 2020 012060 10.1088/1742-6596/1676/1/012060
232 Mu'azu N.D. Jarrah N. Kazeem T.S. Zubair M. Al-Harthi M. Bentonite-layered double hydroxide composite for enhanced aqueous adsorption of Eriochrome Black T Appl. Clay Sci. 161 2018 23 34 10.1016/j.clay.2018.04.009
233 Chen Y. Peng J. Xiao H. Peng H. Bu L. Pan Z. He Y. Chen F. Wang X. Li S. Adsorption behavior of hydrotalcite-like modified bentonite for Pb2+, Cu2+ and methyl orange removal from water Appl. Surf. Sci. 420 2017 773 781 10.1016/j.apsusc.2017.05.138
234 Bin Jiang D. Jing C. Yuan Y. Feng L. Liu X. Dong F. Dong B. Zhang Y.X. 2D-2D growth of NiFe LDH nanoflakes on montmorillonite for cationic and anionic dye adsorption performance J. Colloid Interface Sci. 540 2019 398 409 10.1016/j.jcis.2019.01.022 30665166
235 Dong Y. Ma L. Zhou Q. Effect of the incorporation of montmorillonite-layered double hydroxide nanoclays on the corrosion protection of epoxy coatings J. Coatings Technol. Res. 10 2013 909 921 10.1007/s11998-013-9519-x
236 Yang S. Huang Z. Li C. Li W. Yang L. Wu P. Individual and simultaneous adsorption of tetracycline and cadmium by dodecyl dimethyl betaine modified vermiculite Colloids Surfaces A Physicochem. Eng. Asp. 602 2020 125171 10.1016/j.colsurfa.2020.125171
237 Ma L. Su X. Xi Y. Wei J. Liang X. Zhu J. He H. The structural change of vermiculite during dehydration processes: a real-time in-situ XRD method Appl. Clay Sci. 183 2019 105332 10.1016/j.clay.2019.105332
238 Ahmed Z. Wu P. Jiang L. Liu J. Ye Q. Yang Q. Zhu N. Enhanced simultaneous adsorption of Cd(II) and Pb(II) on octylamine functionalized vermiculite Colloids Surfaces A Physicochem. Eng. Asp. 604 2020 125285 10.1016/j.colsurfa.2020.125285
239 Liu M. Feng J. Mo W. Su X. Fu L. A novel quantitative analysis method of microwave energy absorption during vermiculite expansion process Thermochim. Acta. 691 2020 178718 10.1016/j.tca.2020.178718
240 Tian W. Li Z. Ge Z. Xu D. Zhang K. Self-assembly of vermiculite-polymer composite films with improved mechanical and gas barrier properties Appl. Clay Sci. 180 2019 105198 10.1016/j.clay.2019.105198
241 Stawiński W. Węgrzyn A. Mordarski G. Skiba M. Freitas O. Figueiredo S. Sustainable adsorbents formed from by-product of acid activation of vermiculite and leached-vermiculite-LDH hybrids for removal of industrial dyes and metal cations Appl. Clay Sci. 161 2018 6 14 10.1016/j.clay.2018.04.007
242 Li P. Zhu M. Tian Z. Han Y. Zhang Y. Zhou T. Kang L. Dan J. Guo X. Yu F. Wang Q. Dai B. Two-dimensional layered double hydroxide derived from vermiculite waste water supported highly dispersed Ni nanoparticles for CO methanation Catalysts 7 2017 79 10.3390/catal7030079
243 Zhao S. Meng Z. Fan X. Jing R. Yang J. Shao Y. Liu X. Wu M. Zhang Q. Liu A. Removal of heavy metals from soil by vermiculite supported layered double hydroxides with three-dimensional hierarchical structure Chem. Eng. J. 390 2020 124554 10.1016/j.cej.2020.124554
244 Xing X. Zhou D. Tang E. Liu S. Chu X. Xu X. Xu Y. A novel method to control the release rate of halloysite encapsulated Na2MoO4 with Ca2+ and corrosion resistance for Q235 steel Appl. Clay Sci. 188 2020 105492 10.1016/j.clay.2020.105492
245 Tully J. Fakhrullin R. Lvov Y. Halloysite clay nanotube composites with sustained release of chemicals Bardosova M. Wagner T. Nanomater. Nanoarchitectures 2015 Springer Netherlands Dordrecht 87 118 10.1007/978-94-017-9921-8_5
246 Beryl J.R. Xavier J.R. Mechanical and corrosion protection properties of polymer–clay nanocomposite coatings for mild steel in marine environment Emergent Mater 3 2020 75 85 10.1007/s42247-020-00073-6
247 Matusik J. Hyla J. Maziarz P. Rybka K. Leiviskä T. Performance of halloysite-Mg/Al LDH materials for aqueous As(V) and Cr(VI) removal Materials (Basel) 12 2019 3569 10.3390/ma12213569 31683513
248 Matusik J. Rybka K. Removal of chromates and sulphates by Mg/Fe LDH and heterostructured LDH/Halloysite materials: efficiency, selectivity, and stability of adsorbents in single- and multi-element systems Materials (Basel) 12 2019 1373 10.3390/ma12091373 31035314
249 Wang Y. Liu C. Zhang Y. Zhang B. Liu J. Facile fabrication of flowerlike natural nanotube/layered double hydroxide composites as effective carrier for lysozyme immobilization ACS Sustain. Chem. Eng. 3 2015 1183 1189 10.1021/acssuschemeng.5b00104
250 Wang J. Zhang Y. Si J. Zhang W. Liang Q. Li W. Jin B. Miao S. Structural engineering of NiFe-Layered double hydroxides and halloysite composites for efficient CO2 capture Chem. Eng. J. 463 2023 142502 10.1016/j.cej.2023.142502
251 Luo W. Hu Q. Fan Z. Wan J. He Q. Huang S. Zhou N. Song M. Zhang J. Zhou Z. The effect of different particle sizes and HCl-modified kaolin on catalytic pyrolysis characteristics of reworked polypropylene plastics Energy 213 2020 119080 10.1016/j.energy.2020.119080
252 Kirdeciler S.K. Akata B. One pot fusion route for the synthesis of zeolite 4A using kaolin Adv. Powder Technol. 31 2020 4336 4343 10.1016/j.apt.2020.09.012
253 Aragaw T.A. Angerasa F.T. Synthesis and characterization of Ethiopian kaolin for the removal of basic yellow (BY 28) dye from aqueous solution as a potential adsorbent Heliyon 6 2020 e04975 10.1016/j.heliyon.2020.e04975 32995640
254 Deng L. Shi Z. Synthesis and characterization of a novel Mg–Al hydrotalcite-loaded kaolin clay and its adsorption properties for phosphate in aqueous solution J. Alloys Compd. 637 2015 188 196 10.1016/j.jallcom.2015.03.022
255 Deng L. Shi Z. Li B. Yang L. Luo L. Yang X. Adsorption of Cr(VI) and phosphate on Mg–Al hydrotalcite supported kaolin clay prepared by ultrasound-assisted coprecipitation method using batch and fixed-bed systems Ind. Eng. Chem. Res. 53 2014 7746 7757 10.1021/ie402917s
256 Jung J.-S. Hong G.H. Park J.I. Yang E.-H. Hodala J.L. Moon D.J. Effect of cobalt supported on meso–macro porous hydrotalcite in Fischer–Tropsch synthesis RSC Adv 6 2016 104280 104293 10.1039/C6RA17206G
257 Largo F. Haounati R. Akhouairi S. Ouachtak H. El Haouti R. El Guerdaoui A. Hafid N. Santos D.M.F. Akbal F. Kuleyin A. Jada A. Addi A.A. Adsorptive removal of both cationic and anionic dyes by using sepiolite clay mineral as adsorbent: experimental and molecular dynamic simulation studies J. Mol. Liq. 318 2020 114247 10.1016/j.molliq.2020.114247
258 Pei P. Sun Y. Wang L. Liang X. Xu Y. In-situ stabilization of Cd by sepiolite co–applied with organic amendments in contaminated soils Ecotoxicol. Environ. Saf. 208 2021 111600 10.1016/j.ecoenv.2020.111600
259 García-López D. Fernández J.F. Merino J.C. Santarén J. Pastor J.M. Effect of organic modification of sepiolite for PA 6 polymer/organoclay nanocomposites Compos. Sci. Technol. 70 2010 1429 1436 10.1016/j.compscitech.2010.05.020
260 Charradi K. Ahmed Z. Cid R.E. Aranda P. Ruiz-Hitzky E. Ocon P. Chtourou R. Amelioration of PEMFC performance at high temperature by incorporation of nanofiller (sepiolite/layered double hydroxide) in Nafion membrane Int. J. Hydrogen Energy. 44 2019 10666 10676 10.1016/j.ijhydene.2019.02.183
261 Jin L. Zeng H.-Y. Xu S. Chen C.-R. Duan H.-Z. Du J.-Z. Hu G. Sun Y.-X. Facile preparation of sepiolite@LDH composites for the visible-light degradation of organic dyes Chinese J. Catal. 39 2018 1832 1841 10.1016/S1872-2067(18)63120-1
262 Gómez-Avilés A. Aranda P. Ruiz-Hitzky E. Layered double hydroxide/sepiolite heterostructured materials Appl. Clay Sci. 130 2016 83 92 10.1016/j.clay.2015.12.011
263 Yu Z. Li X. Peng Y. Min X. Yin D. Shao L. MgAl-layered-double-hydroxide/sepiolite composite membrane for high-performance water treatment based on layer-by-layer hierarchical architectures Polymers (Basel) 11 2019 525 10.3390/polym11030525 30960508
264 Wang W. Wang A. Recent progress in dispersion of palygorskite crystal bundles for nanocomposites Appl. Clay Sci. 119 2016 18 30 10.1016/j.clay.2015.06.030
265 Rouhaninezhad A.A. Hojati S. Masir M.N. Adsorption of Cr (VI) onto micro- and nanoparticles of palygorskite in aqueous solutions: effects of pH and humic acid Ecotoxicol. Environ. Saf. 206 2020 111247 10.1016/j.ecoenv.2020.111247
266 García-Rivas J. Suárez M. García-Romero E. Sánchez del Río M. Presence of oriented fibers in palygorskite powders and its influence on X-Ray diffractograms Appl. Clay Sci. 195 2020 105724 10.1016/j.clay.2020.105724
267 Mu B. Wang A. Adsorption of dyes onto palygorskite and its composites: a review J. Environ. Chem. Eng. 4 2016 1274 1294 10.1016/j.jece.2016.01.036
268 Zhang Z. Gui W. Wei J. Cui Y. Li P. Jia Z. Kong P. Functionalized attapulgite for the adsorption of methylene blue: synthesis, characterization, and adsorption mechanism ACS Omega 6 2021 19586 19595 10.1021/acsomega.1c02111 34368545
269 Morais A.Í.S. Oliveira W.V. de Oliveira V.V. Honorio L.M.C. Araujo F.P. Bezerra R.D.S. Fechine P.B.A. Viana B.C. Furtini M.B. Silva-Filho E.C. Osajima J.A. Semiconductor supported by palygorskite and layered double hydroxides clays to dye discoloration in solution by a photocatalytic process J. Environ. Chem. Eng. 7 2019 103431 10.1016/j.jece.2019.103431
270 Meng Z. Wang Y. Xin X. Liu H. Yan Y. Yan F. Enhanced fretting wear performance of UHMWPE composites by grafting Co–Ni layered double hydroxides on attapulgite nanofibers Tribol. Int. 153 2021 106628 10.1016/j.triboint.2020.106628
271 Tomás H. Alves C.S. Rodrigues J. Laponite®: a key nanoplatform for biomedical applications? Nanomedi Nanotechnol., Biol. Med. 14 2018 2407 2420 10.1016/j.nano.2017.04.016
272 Labanda J. Sabaté J. Llorens J. Rheology changes of Laponite aqueous dispersions due to the addition of sodium polyacrylates of different molecular weights Colloids Surfaces A Physicochem. Eng. Asp. 301 2007 8 15 10.1016/j.colsurfa.2007.01.011
273 Napruszewska B.D. Michalik-Zym A. Dula R. Duraczyńska D. Rojek W. Socha R.P. Lityńska-Dobrzyńska L. Bahranowski K. Serwicka E.M. VOCs combustion catalysts based on composites of exfoliated organo-Laponite and multimetallic (Mn, Al, Zr, Ce) hydrotalcites prepared by inverse microemulsion Catal. Today. 333 2019 182 189 10.1016/j.cattod.2018.03.043
274 Napruszewska B.D. Michalik-Zym A. Dula R. Bielańska E. Rojek W. Machej T. Socha R.P. Lityńska-Dobrzyńska L. Bahranowski K. Serwicka E.M. Composites derived from exfoliated Laponite and Mn-Al hydrotalcite prepared in inverse microemulsion: a new strategy for design of robust VOCs combustion catalysts Appl. Catal. B Environ. 211 2017 46 56 10.1016/j.apcatb.2017.04.030
275 Napruszewska B.D. Michalik A. Walczyk A. Duraczyńska D. Dula R. Rojek W. Lityńska-Dobrzyńska L. Bahranowski K. Serwicka E.M. Composites of Laponite and Cu–Mn hopcalite-related mixed oxides prepared from inverse microemulsions as catalysts for total oxidation of toluene Materials (Basel) 11 2018 1365 10.3390/ma11081365 30082673
276 Li L. Gu Z. Gu W. Liu J. Xu Z.P. Efficient drug delivery using SiO 2 -layered double hydroxide nanocomposites J. Colloid Interface Sci. 470 2016 47 55 10.1016/j.jcis.2016.02.042 26930539
277 Zhu Y. Zhu R. Wang M. Wu B. He X. Qian Y. Wang S. Anti-metastatic and anti-angiogenic activities of core–shell SiO2@LDH loaded with etoposide in non-small cell lung cancer Adv. Sci. 3 2016 1600229 10.1002/advs.201600229
278 Wang J. Zhu R. Gao B. Wu B. Li K. Sun X. Liu H. Wang S. The enhanced immune response of hepatitis B virus DNA vaccine using SiO2@LDH nanoparticles as an adjuvant Biomaterials 35 2014 466 478 10.1016/j.biomaterials.2013.09.060 24099705
279 Wang K. Huang X. Liu Y. Fei W. Gu Z. Different morphologies of SiO2@Mg-Al-LDH nanocomposites as catalyst for the synthesis of propylene glycol methyl ether J. Nanopart. Res. 22 2020 126 10.1007/s11051-020-04868-w
280 Prins R. On the structure of γ-Al2O3 J. Catal. 392 2020 336 346 10.1016/j.jcat.2020.10.010
281 Samain L. Jaworski A. Edén M. Ladd D.M. Seo D.-K. Javier Garcia-Garcia F. Häussermann U. Structural analysis of highly porous γ-Al2O3 J. Solid State Chem. 217 2014 1 8 10.1016/j.jssc.2014.05.004
282 Lv L. Bo Y. Ji D. Han W. Liu H. Gao X. Xu C. Liu H. Layered double hydroxide method for preparing Ni–Mo/γ-Al2O3 ultradeep hydrodesulfurization catalysts Ind. Eng. Chem. Res. 57 2018 13889 13894 10.1021/acs.iecr.8b03383
283 Li S. Ribeiro A.M. Shi Y. Moreira M.N. Cai N. Rodrigues A.E. Synthesis, pelleting, and performance evaluation of a novel K-promoted γ-alumina/MgAl-layered double oxide composite adsorbent for warm gas H2/CO2 separation Ind. Eng. Chem. Res. 54 2015 7154 7163 10.1021/acs.iecr.5b01342
284 Ponomar V.P. Bagmut M.M. Kalinichenko E.A. Brik A.B. Experimental study on oxidation of synthetic and natural magnetites monitored by magnetic measurements J. Alloys Compd. 848 2020 156374 10.1016/j.jallcom.2020.156374
285 Hao J. Qu T. Wang Q. Zhao Z. Preparation and visible light responsive photocatalytic activity of Fe3O4/Ni-Al-Ce LDH/Bi2WO6 composites Quim. Nova. 40 2017 849 853 10.21577/0100-4042.20170062
286 Bi X. Fan T. Zhang H. Novel morphology-controlled hierarchical core@shell structural organo-layered double hydroxides magnetic nanovehicles for drug release ACS Appl. Mater. Interfaces. 6 2014 20498 20509 10.1021/am506113s 25340738
287 Shahabadi N. Razlansari M. Zhaleh H. Mansouri K. Antiproliferative effects of new magnetic pH-responsive drug delivery system composed of Fe3O4, CaAl layered double hydroxide and levodopa on melanoma cancer cells Mater. Sci. Eng. C. 101 2019 472 486 10.1016/j.msec.2019.04.004
288 Pan D. Zhang H. Fan T. Chen J. Duan X. Nearly monodispersed core–shell structural Fe3O4@DFUR–LDH submicro particles for magnetically controlled drug delivery and release Chem. Commun. 47 2011 908 910 10.1039/C0CC01313G
289 Tuncelli G. Ay A.N. Zümreoglu-Karan B. 5-Fluorouracil intercalated iron oxide@layered double hydroxide core-shell nano-composites with isotropic and anisotropic architectures for shape-selective drug delivery applications Mater. Sci. Eng. C. 55 2015 562 568 10.1016/j.msec.2015.06.001
290 Pandi K. Periyasamy S. Viswanathan N. Remediation of fluoride from drinking water using magnetic iron oxide coated hydrotalcite/chitosan composite Int. J. Biol. Macromol. 104 2017 1569 1577 10.1016/j.ijbiomac.2017.02.037 28214583
291 Sun G. Li Y. Cai Z. Teng Y. Wang Y. Reaney M.J.T. K2CO3-loaded hydrotalcite : a promising heterogeneous solid base catalyst for biolubricant base oil production from waste cooking oils Appl. Catal. B Environ. 209 2017 118 127 10.1016/j.apcatb.2017.02.078
292 Sun C. Qiu F. Yang D. Ye B. Preparation of biodiesel from soybean oil catalyzed by Al-Ca hydrotalcite loaded with K2CO3 as heterogeneous solid base catalyst Fuel Process. Technol. 126 2014 383 391 10.1016/j.fuproc.2014.05.021
293 Palza H. Delgado K. Govan J. Novel magnetic CoFe2O4/layered double hydroxide nanocomposites for recoverable anionic adsorbents for water treatment Appl. Clay Sci. 183 2019 105350 10.1016/j.clay.2019.105350
294 Zhao G. Liu L. Li C. Yu J. Jiao F. Synthesis, characterization and enhanced visible light photocatalytic activity of Bi2WO6/Ni–Al layered double hydroxide composites J. Mater. Sci. Mater. Electron. 29 2018 14008 14021 10.1007/s10854-018-9533-y
295 Abdel-Hady E.E. Mahmoud R. Hafez S.H.M. Mohamed H.F.M. Hierarchical ternary ZnCoFe layered double hydroxide as efficient adsorbent and catalyst for methanol electrooxidation J. Mater. Res. Technol. 17 2022 1922 1941 10.1016/j.jmrt.2022.01.042
296 Wang Q. Wang X. He H. Chen W. Fabrication of Hollow LDH nanocages using ZIF-67 template as superb adsorbent for anionic organic pollutant J. Porous Mater. 28 2021 471 480 10.1007/s10934-020-01007-7
297 Turk T. Boyraz T. Alp İ. Arsenic removal by layered double hydroxides (LDH): a mini review Water Pract. Technol. 19 2024 2088 2107 10.2166/wpt.2024.111
298 Tang Z. Qiu Z. Lu S. Shi X. Functionalized layered double hydroxide applied to heavy metal ions absorption: a review Nanotechnol. Rev. 9 2020 800 819 10.1515/ntrev-2020-0065
299 Moustafa D. Mahmoud R. El-Salam H.M.A. Shehata N. Utilization of residual zinc–iron-layered double hydroxide after methyl orange management as a new sorbent for wastewater treatment Appl. Nanosci. 11 2021 709 723 10.1007/s13204-020-01632-3
300 Kamal W. Mahmoud R. Allah A.E. Abdelwahab A. Taha M. Farghali A.A. Insights into synergistic utilization of residual of ternary layered double hydroxide after oxytetracycline as a potential catalyst for methanol electrooxidation Chem. Eng. Res. Des. 188 2022 249 264 10.1016/j.cherd.2022.09.041
301 KAMEL M. EL-FATAH G.A. ZAHER A. FARGHALI A.A. OTHMAN S.I. ALLAM A.A. RUDAYNI H.A. SALAH A.M. HASSOUNA M.E.M. MAHMOUD R. Cost-effective layered double hydroxides/conductive polymer nanocomposites for electrochemical detection of wastewater pollutants Chinese J. Anal. Chem. 52 2024 100368 10.1016/j.cjac.2024.100368
302 Kameliya J. Verma A. Dutta P. Arora C. Vyas S. Varma R.S. Layered double hydroxide materials: a review on their preparation, characterization, and applications Inorganics 11 2023 121 10.3390/inorganics11030121
303 Medeiros de Paula G. do Nascimento Rocha de Paula L. Freire Rodrigues M.G. Production of MCM-41 and SBA-15 hybrid silicas from industrial waste Silicon 14 2022 439 447 10.1007/s12633-020-00831-5
304 Wen J. Yang K. Huang J. Sun S. Recent advances in LDH-based nanosystems for cancer therapy Mater. Des. 198 2021 109298 10.1016/j.matdes.2020.109298
305 Yang Z. Wang F. Zhang C. Zeng G. Tan X. Yu Z. Zhong Y. Wangab H. Cui F. Utilization of LDH-based materials as potential adsorbents and photocatalysts for the decontamination of dyes wastewater: a review RSC Adv. 6 2016 79415 10.1039/c6ra12727d
