Layered Silicate Magadiite Research Articles

A strategy for the efficient removal of acidic and basic dyes in wastewater by organophilic magadiite@alginate beads: Box-Behnken Design optimization

In this study, four adsorbents were developed: layered silicate magadiite material (mag), Hexadecyltrimethylammonium intercalated magadiite (HDTMA@mag), a cross-linked composite of sodium alginate and magadiite (ALG@mag) and a cross-linked composite of sodium alginate and HDTMA@magadiite (ALG@HDTMA@mag). The adsorbents were evaluated for their effectiveness in removing of Methylene Blue (MB) and Eriochrome Black T (EBT) dyes. The prepared adsorbents were characterized using SEM, XRD, FTIR, and zeta potential measurements. Kinetic modeling results indicated that both film diffusion and intraparticle diffusion are useful as rate-determining processes in adsorption for all adsorbents. For both dyes, the Langmuir isotherm model provided a good correlation with the adsorption equilibrium data. ANOVA analysis for the best adsorbent (ALG@HDTMA@mag beads) revealed that MB removal was significantly influenced by the positive individual effects of contact time and ALG@HDTMA@mag dose. However, the individual effect of MB concentration exhibited an antagonistic effect throughout the adsorption process. The optimal parameters for achieving an adsorption capacity of 118.54 mg/g were a dye concentration of 60 ppm, a contact period of 1800 min, and an ALG@HDTMA@mag dose of 50 mg.

Synthesis and Crystallization Mechanism for SAPO-34 Zeolite Derived from Magadiite.

In this work, we explored the hydrothermal synthesize and crystallization process of SAPO-34 zeolites from two-dimensional layered silicate magadiite by using tetraethylammonium hydroxide (TEAOH) as a templating agent. Comprehensive characterization was conducted by XRD, SEM, FTIR, Raman, and BET. Time-resolved PXRD analysis revealed that SAPO-34 zeolite exhibited a steep growth curve when the crystallization time was 30 h, and the crystallinity reached 98.65 % at 48 h. Specifically, the disruption of the magadiite layer exposed charged silanol groups on the surface, fostering an affinity for AlO4 and PO4 species, thereby initiating the nucleation process. Under the guidance of TEAOH, these nucleation sites transformed into SAPO-34 nuclei, gradually advancing towards crystallization. FTIR and Raman analyses affirmed the presence of 6Rs, followed by D6R and 4Rs SBUs, along with the characteristic CHA structure. Combined with 29Si NMR established that disaggregated silicate minerals served as zeolite synthesis "seeds", enhancing nucleation sites and overall crystallization efficiency.

Bridging the Gap between Zeolites and Dense Silica Polymorphs: Formation of All-Silica Zeolite with High Framework Density from Natural Layered Silicate Magadiite.

A silica zeolite (RWZ-1) with a very high framework density (FD) was synthesized from highly crystalline natural layered silicate magadiite, bridging the gap between the two research areas of zeolites and dense silica polymorphs. Magadiite was topotactically converted into a 3D framework through two-step heat treatment. The resulting structure had a 1D micropore system of channel-like cavities with an FD of 22.1 Si atoms/1000 Å3 . This value is higher than those of all other silica zeolites reported so far, approaching those of silica polymorphs (tridymite (22.6) and α-quartz (26.5)). RWZ-1 is a slight negative thermal expansion material with thermal properties approaching those of dense silica polymorphs. It contributes to the creation of a new field on microporous high-density silica/silicates. Synergistic interactions are expected between the micropores with molecular sieving properties and the dense layer-like building units with different topologies which provide thermal and mechanical stabilities.

Fabrication of Nitrogen-containing Nanocarbons for the Detection of Hydrogen Peroxide Utilizing Layered Silicate Magadiite as a Template

Fabrication of Nitrogen-containing Nanocarbons for the Detection of Hydrogen Peroxide Utilizing Layered Silicate Magadiite as a Template

Layered silicate magadiite–derived three-dimensional honeycomb-like cobalt–nickel silicates as excellent cathode for hybrid supercapacitors

Developing low-cost electrode materials with high performance is the priority among priorities for large-scale application of supercapacitors (SCs). Magadiite, the most ubiquitous material on Earth, is half-abandoned and half-forgotten, and it is extremely valuable for development to useful materials, such as ‘a potential stock’ to be developed. Herein, we conceive the transformation of magadiite to electrode materials, pursuing the aim ‘waste can be turned into treasure’. Fortunately, three-dimensional honeycomb-like cobalt–nickel silicate (CoxNi2-xSiO4) as high-performance electrode material for SCs is achieved via two simple steps of exfoliation and hydrothermal process. The bimetallic synergistic effect derived from Co/Ni can improve the reactivity of the material, and the honeycomb-like morphology can facilitate ion migration, so the electrochemical properties are enhanced. As a consequence, the CoxNi2-xSiO4 electrode exhibited a specific capacitance of 1,097 F/g (548 C/g) at 0.5 A/g, as well as excellent cyclic stability of 101% retention after 10,000 cycles. The hybrid SC device is assembled by CoxNi2-xSiO4 and active carbon (CoxNi2-xSiO4//AC), and it delivers an excellent energy density of 15.5 Wh/m2 at a power density of 1.34 W/m2 and cycling stability (100% after 10,000 cycles). This work not only realizes the transformation of magadiite to transition metal silicates (TMSs) as electrode materials for high-performance SCs but also broadens the application of magadiite and opens up a novel strategy for synthesizing TMSs.

Rapid Combustion Synthesis of Metal Oxides Species Highly Dispersed on Layered Silicate Magadiite

AbstractThe good dispersion of metal oxides (MOs) with ultra‐small particles on host materials is essential for improving the utilization efficiency and increasing the service life. Herein, a novel strategy is developed as a methodology to synthesize MOs species highly dispersed on layered silicate magadiite by a rapid combustion method within 30 s. The speediness of the combustion process can avoid the agglomeration of MOs and well‐defined layered structure can further restrict the growth of nanoparticles. Thus, the lamellar structure of magadiite is well‐kept and MOs species with the particle size less than 5 nm immerse on the lamellar platelets. The results demonstrate this process can be considered as a methodology to synthesize different MOs species highly dispersed on various host materials for high efficiency applications.

Properties of layered [Al]- and [V,Al]-magadiite catalysts as revealed by ethanol dehydration

Abstract This work describes the synthesis of the layered silicate magadiite and the insertion of V and/or Al (Si/V = 33 and Si/Al = 15 M ratios) by the seed-induced crystallization method (SIC), aiming at studying the influence of these heteroatoms in the ethylene production through the ethanol dehydration reaction. The preparation of these materials without contaminating phases or amorphization was observed by X-ray diffraction, and the presence of single and double rings characteristic of the magadiite structure was confirmed by FTIR. The presence of structural Al in tetrahedral and octahedral coordination was verified by 27Al-NMR, while the acid sites generated by the presence of this heteroatom were confirmed by TPD-NH3. In addition, this work reports for the first time a quantitative study of the use of magadiite-based lamellar catalysts in the production of ethylene from ethanol. Among the catalysts studied, the ones that generated the highest ethanol conversion, selectivity and yield to ethylene were those containing only structural aluminum ([Al]-maga-(V), [Al]-maga-(Si) and [Al]-maga-(Al)). The least active and selective to ethylene was pure silicon magadiite (maga-(Si)), which presented low ethanol conversion and higher selectivity to acetaldehyde and diethylether. Worse results were obtained for the lamellar catalysts where aluminum and vanadium were together in the framework ([V,Al]-maga-(Si), [V,Al]-maga-(Al) and [V,Al]-maga-(V)). In general, these results show that layered solids can be interesting catalysts in reaction where framework acidity is needed and are stable at high temperatures even in the presence of the water produced in the reaction.

Understanding the role of Zn2+ in surfactant-free layered silicate delamination: Exfoliation of magadiite

Abstract We investigated the effect of Zn2+ treatment on the exfoliation of layered silicate magadiite, as a model system, to better understand the role of zinc in surfactant-free zeolite exfoliation. Samples of magadiite and ball-milled magadiite were exfoliated via treatment with aqueous Zn(NO3)2 solution, and the resulting materials were characterized via powder X-ray diffraction, nitrogen physisorption, high-angle annular dark-field scanning transmission electron microscopy, and infrared spectroscopy. Zn2+ treatment of magadiite increases its external surface area by 40%, while Zn2+ treatment of ball-milled magadiite increases its external surface area by 109%. Acid-washing removes Zn(O)x(OH)y colloids and further increases external surface area, leading to a total surface area increase of 150% for magadiite after Zn2+ treatment and acid-washing, and 182% for ball-milled magadiite after Zn2+ treatment and acid-washing, by exposing surface area that was not accessible after Zn2+ treatment due to pore blocking. We propose a mechanism of exfoliation to account for these surface-area increases, which involves the Zn(O)x(OH)y colloids growing and forcing layers apart selectively at the grain boundaries. Ball milling not only makes existing grain boundaries more accessible, but it also creates new grain boundaries, resulting in more efficient exfoliation.

Fe3O4 nanoparticles/polymer immobilized on silicate platelets for crude oil recovery

A novel nanocomposite containing polymer and iron-oxide nanoparticles in the interlayer space of layered silicate magadiite (mag) was synthesized by ion-exchange and co-precipitated method. Mag was first modified with poly(oxypropylene)amine salts (POP at 2000 and 4000 g/mol Mw). The interlayer space could be effectively expanded from 1.5 to 6.4 and 11.4 nm, respectively, by controlling the amount of POP intercalated. The expanded basal space is suitable for iron oxide nanoparticles embedded. During the ion-exchanging and co-precipitating of iron species, there's an unwanted “crowding-out effect” that release POP molecules, which lead to the mag couldn't encapsulate iron oxide nanoparticles in a certain amount. The existence of high molecular weight POP4000 and low temperature (<4 °C) facilitate a better dispersion in reaction is adaptable for exchanging for Fe2+/Fe3+ ions and generating iron oxide nanoparticles. By changing the proportions of iron oxide and POP, the final synthesized POP4000-mag-iron oxide was constituted of 14% iron oxide and 60 wt % POP. The synthesized nanoparticles comprising of POP molecules and iron oxide could be applied as a crude oil absorbent due to its ability to absorb crude oil and it is recyclable under a magnetism.

Biopolymer-layered polysilicate micro/nanocomposite based on chitosan intercalated in magadiite

On the basis of their high adsorption and cation exchange capacity, swelling potential and low toxicity, layered sodium silicate magadiite (Na–magadiite) is an attractive solid for intercalation of polymers. This study envisages the intercalation of cationic biopolymer chitosan (Chit) in Na–magadiite to prepare a Chit/magadiite micro/nanocomposite. Characterisation of starting-magadiite, pure chitosan and Chit/magadiite were investigated using powder X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy and thermal analysis. XRD confirmed that the chitosan had been intercalated into the interlayer space of magadiite by increasing the basal spacing, d001 from 15.6 A to 21.45 A. The presence of characteristic bands of biopolymer and layered silicate in Chit/magadiite were confirmed by FTIR analysis. The thermal stability of micro/nanocomposite was evaluated by thermogravimetry analysis. The results suggested the formation of electrostatic interactions by protonated amine groups with the negatively charged magadiite surface as well as intercalation in the form of a predominant monolayer arrangement of chitosan chains in layered silicate magadiite.

Intercalation of hydrophilic antibiotic into the interlayer space of the layered silicate magadiite

The hydrophilic antibiotic ampicillin (Amp) molecule was intercalated into the layered silicic acid magadiite (H2Si14O29, nH2O), from aqueous solution. The starting as-synthesized Na-magadiite, H-magadiite and ampicillin-intercalated magadiite (amp-magadiite) materials as well as free ampicillin were characterized by X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy and thermal (TG) analysis. The morphology of the solids was determined by scanning electron microscopy (SEM) analysis. All the characterization techniques shows that ampicillin is intercalated in the interlayer space of magadiite and that is strongly bound to the silicate layer through probably strong hydrogen bonds with the terminal SiOH groups. According to the results obtained a structural model was proposed. This Amp-magadiite material may constitute a new drug delivery system or may also be used as an antibacterial material.

Solid-solid intercalation and optical properties of VO-8-hydroxyquinoline decoration of layered silicate magadiite

AbstractCoordination of vanadyl (VO2+) ions with 8-hydroxyquinoline (8Hq) in the interlayer space of layered silicate magadiite (mag) was realized by solid-solid intercalation. Composition, structure and morphology of this compound were studied by X-ray diffraction (XRD), Fourier-transform infrared spectrometry (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma atomic emission spectroscopy (ICP-AES). The obtained results indicate that the basal spacing of decorated mag increased after intercalation and suggest that VO-8Hq decorated into the interlayer of mag (VO-mag-8Hq) was successfully synthesized for the first time. Optical properties of VO-mag-8Hq were studied by ultraviolet-visible (UV-Vis) and photoluminescence spectroscopy (PL). The findings reveal that VO-8Hq complexes in the interlayer space exhibit extraordinary fluorescence properties and the confined space of mag influences the optical properties of VO-8Hq complexes.

Intercalation and in situ formation of coordination compounds with ligand 8-hydroxyquinoline-5-sulfonic acid in the interlayer space of layered silicate magadiite by solid-solid reactions

Intercalation and in situ formation of three fluorescent complexes, Al(III)-, Ca(II)- and Zn(II)-8-hydroxyquinoline-5-sulfonic acid (M-8HqS, M = Al, Ca and Zn) in the interlayer spaces of magadiite (mag) were synthesized by solid-solid reactions between metal ions exchanged mags (M-mag, M = Al, Ca and Zn) and 8HqS at room temperature. The intercalation and in situ formation of 8HqS molecules into the interlayer spaces of M-mags were evaluated by XRD, ICP-AES, EDS, elemental mappings, TG/DTA, elemental analysis, FE-SEM, FTIR, UV-Vis, PL and XPS. Results show that the basal spacings of the intercalated composites increase after the intercalation of 8HqS into M-mags. A new peak at 1461 cm−1 is observed, supporting the formation of the coordination complexes between 8HqS and metal cations. The slight shift of the absorption and luminescence bands of the complexes suggests the different microstructures including molecular packing of the complexes in the interlayer spaces of mags, which indicating that the process is a host-guest interaction. The amount of 8HqS in the intercalated compounds is different due to the diversification of coordination ability of metal ions, and the order of the coordination ability of these three metal ions is Ca2+ > Zn2+ > Al3+. The amount of the metal cations (Al3+, Ca2+ and Zn2+) in the interlayer of mag is enough for the in situ complex formation of M-8HqS complexes. Thus, the intercalation and in situ formation of M-8HqS complexes (M = Al, Ca and Zn) in the interlayer space of mag are successfully achieved in the present work.

Mechanistic study on the synthesis of ZSM-5 from a layered silicate magadiite

The transformation mechanism for zeolite ZSM-5 from magadiite in the present of tetrapropylammonium cations has been investigated. It is found that the transformation subjects no complete or extensive dissolution of magadiite. What's more, the transformation is beginning with the formation of linear channels rather than the zig-zag channels. On the basis of these observations, we proposed that the magadiite layers were reconfigured into linear chains with the structure direction of tetrapropylammonium cations in the initial stage, and then zig-zag channels were constructed by connection of linear channels. In this way, the framework of ZSM-5 was formed.

Intercalation of calcein into layered silicate magadiite and their optical properties.

Calcein–Ca (II), Zn (II) and Al (III) complexes were successfully intercalated into interlayer surfaces of layered silicate magadiite and fluorescence properties of organic metal-chelates in the confined spaces were investigated. Structures, compositions and morphologies of the intercalated magadiites were adequately studied by tests, including X-ray diffraction, energy-dispersive X-ray spectrometer, elemental mapping, X-ray photoelectron spectroscopy, inductively coupled plasma atomic emission spectroscopy, Fourier-transform infrared spectra, ultraviolet–visible spectroscopy, thermo-gravimetric analysis, differential thermal analysis and scanning electron microscopy. Results confirmed that metal–organic chelate species were immobilized onto the silicate sheets via solid-state interaction. Basal spacings between silicate layers decreased by exchanged metal ions and increased after intercalation of calcein into the interlayer spaces of cation-exchanged magadiites. The encapsulation was obtained by a flexible solid–solid reaction, and the present reaction and products had a potential of application to industrial uses. A speculative mechanism was proposed for reaction by solid-state intercalation. Furthermore, it was found that the complexes in the interlayer space also exhibited special fluorescence properties. The significance of this current work was that it provided a possible route for synthesizing metal–organic complexes that encapsulated in phyllosilicate.

Magadiite as a support for the controlled release of herbicides

Diuron and 2,4-dichlorophenoxyacetic acid were intercalated into layered silicate magadiite and the presence of anchored herbicides within the lamellas was confirmed by Fourier transform infrared spectroscopy. X-ray diffraction patterns and surface area analysis showed that the intercalation of herbicides decreased basal lamellar spacing and the surface area of the silicate. According to the results obtained from surface charge analysis, the main interactions between magadiite and the herbicides were mediated by hydrogen bond formation. Controlled release studies demonstrated that the delivery of the herbicides occurred substantially faster at pH 9, while the difference in delivery rates at pH 1 and pH 4.6 (the point of zero charge) was far less marked, although release at the more acidic pH was slightly quicker. The use of magadiite as a herbicide support shows great potential for the development of controlled release systems and will contribute to more sustainable forms of weed control.

Application of Synthetic Layered Sodium Silicate Magadiite Nanosheets for Environmental Remediation of Methylene Blue Dye in Water.

The removal of methylene blue (MB) dye from water was investigated using synthetic nano-clay magadiite (SNCM). SNCM was synthesized by a hydrothermal treatment under autogenous pressure. A rosette-shaped single mesoporous magadiite phase with 16.63 nm average crystallite size and 33 m2∙g−1 Braunauer-Emmet-Teller (BET)-surface area was recorded. The adsorption results indicated the pronounced affinity of the SNCM to the MB dye molecules, which reached an adsorption uptake of 20.0 mg MB dye/g of SNCM. The elimination of MB dye by the SNCM was kinetically and thermodynamically considered; a pseudo-second-order kinetic model was attained, and its spontaneous, chemical, and endothermic nature was verified. SNCM was shown to be robust without a detectable reduction in the adsorption capacity after up to four times re-use.

Preparation and characterization of layered silicate magadiite intercalated by Cu2+ and Zn2+ for antibacterial behavior

The purpose of this work is the synthesis of two series of layered silicate materials with different ratios (10, 30, 50, 80 and 100) of Cu(NO3)2, or Zn(NO3)2 by ion-exchange method. Several analysis techniques have been used such as X-ray diffraction, energy dispersive X-ray spectroscopy, thermogravimetric analysis, scanning electron microscope and Fourier transform infrared spectroscopy. The results revealed that ion-exchange method of copper and zinc with different ratios did not affect the structure of Na-magadiite. The gap between the theoretical and experimental ion-exchange are in agreement. Antibacterial activity test against Escherichia coli, Rhizobium sp. and Staphylococcus demonstrate that when ratio was (30, 50, 80 and 100) the antibacterial activity of the layered silicate materials showed high antibacterial activity.

In situ preparation and optical properties of metal-8-hydroxyquinoline decoration of layered silicate: Self-assembly in the magadiite interface by solid-solid reaction

We succeeded in the self-assembly of 8-hydroxyquinoline (8Hq)-Li (I), Al (III) and Cu (II) complexes into the interlayer surfaces of layered silicate magadiite (Na2Si14O29·nH2O) and investigated the luminescence of organic metal-chelates in the confined spaces. The measurements, including X-ray diffraction (XRD), Fourier-transform infrared spectra (FT-IR), thermo-gravimetric analysis and differential thermal analysis (TG/DTA), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometer (EDS), ultraviolet–visible spectroscopy (UV–Vis) and Photoluminescence spectra (PL), confirmed that the metal-organic chelates species were immobilized onto the silicate sheets via ion-dipole interaction and free diffusion. The encapsulation was obtained by a flexible solid-solid reaction, and the present reaction and products have a potential of application to industrial uses. A speculative mechanism is proposed for reaction by the combination of solid-solid and solid-gas intercalation. Furthermore, it was found that the complexes in the interlayer space showed a special fluorescence property than in the crystal state and the confined space of phyllosilicate shows an influence on properties of complexes. Here, a possibility of synthesizing metal-organic complexes that encapsulated in phyllosilicate is given.

Metal oxide decorated layered silicate magadiite for enhanced properties: insight from ZnO and CuO decoration.

Surface modification of a layered silicate magadiite (mag) was accomplished using cetyltrimethyl ammonium bromide (CTAB), copper oxide (CuO) and zinc oxide (ZnO). All the ions were intercalated using an ion-exchange reaction, and CuO and ZnO are prepared by a precipitation method. A precursor of CTAB modified mag enables good dispersion of the metal oxide on the surface of the lamellas. Characterization techniques (XRD, XRF, TGA, FTIR and XPS spectroscopy) confirmed that CuO and ZnO are homogeneously immobilized onto the silicate sheets of mag. The porosity of the products was explored by BET analysis. SEM and TEM provided the visualization of CuO/ZnO, which were in a good morphology and uniformly distributed on the platelets of the modified mag. Consequently, hybrids with well dispersed metal oxides showed unique properties in photoluminescence and magnetism compared to the metal oxide in the bulk state. The formation mechanism of the synthesis of CuO and ZnO decorated mag was further studied, which can give suggestion for fabricating other metal oxide decorated layered silicates. The significance of this current work is the fact that it provides a new method to prepare well dispersed metal oxides using an easy and flexible precipitation method that can be applied to other layered materials and metal oxides.