Nanoporous Aluminosilicate Research Articles

Nucleic acid vaccine candidates encapsulated with mesoporous silica nanoparticles against MERS-CoV

ABSTRACT Middle East respiratory coronavirus (MERS-CoV) is a newly emergent, highly pathogenic coronavirus that is associated with 34% mortality rate. MERS-CoV remains listed as priority pathogen by the WHO. Since its discovery in 2012 and despite the efforts to develop coronaviruses vaccines to fight against SARS-CoV-2, there are currently no MERS-CoV vaccine that has been approved. Therefore, there is high demand to continue on the development of prophylactic vaccines against MERS-CoV. Current advancements in vaccine developments can be adapted for the development of improved MERS-CoV vaccines candidates. Nucleic acid-based vaccines, including pDNA and mRNA, are relatively new class of vaccine platforms. In this work, we developed pDNA and mRNA vaccine candidates expressing S.FL gene of MERS-CoV. Further, we synthesized a silane functionalized hierarchical aluminosilicate to encapsulate each vaccine candidates. We tested the nucleic acid vaccine candidates in mice and evaluated humoral antibodies response. Interestingly, we determined that the non-encapsulated, codon optimized S.FL pDNA vaccine candidate elicited the highest level of antibody responses against S.FL and S1 of MERS-CoV. Encapsulation of mRNA with nanoporous aluminosilicate increased the humoral antibody responses, whereas encapsulation of pDNA did not. These findings suggests that MERS-CoV S.FL pDNA vaccine candidate induced the highest level of humoral responses. This study will enhance further optimization of nanosilica as potential carrier for mRNA vaccines. In conclusion, this study suggests MERS-CoV pDNA vaccine candidate as a suitable vaccine platform for further pivotal preclinical testings.

Nanoporous aluminosilicate mediated synthesis of 2- and 2,2-substituted 2,3-dihydroquinazolin-4(1H)-ones

Nanoporous silicate materials, made by an operationally simple evaporation-induced self-assembly (EISA) approach, efficiently catalyze the formation of 2-substituted 2,3-dihydroquinazolin-4(1H)-ones from aldehydes and dimethyl acetals. This methodology can be extended to encompass the reaction of ketones and ketals to provide facile access to 2,2-disubstituted and spiro dihydroquinazolin-4(1H)-ones in high yields and short reaction times.

ZeoSyn: A Comprehensive Zeolite Synthesis Dataset Enabling Machine-Learning Rationalization of Hydrothermal Parameters.

Zeolites, nanoporous aluminosilicates with well-defined porous structures, are versatile materials with applications in catalysis, gas separation, and ion exchange. Hydrothermal synthesis is widely used for zeolite production, offering control over composition, crystallinity, and pore size. However, the intricate interplay of synthesis parameters necessitates a comprehensive understanding of synthesis-structure relationships to optimize the synthesis process. Hitherto, public zeolite synthesis databases only contain a subset of parameters and are small in scale, comprising up to a few thousand synthesis routes. We present ZeoSyn, a dataset of 23,961 zeolite hydrothermal synthesis routes, encompassing 233 zeolite topologies and 921 organic structure-directing agents (OSDAs). Each synthesis route comprises comprehensive synthesis parameters: 1) gel composition, 2) reaction conditions, 3) OSDAs, and 4) zeolite products. Using ZeoSyn, we develop a machine learning classifier to predict the resultant zeolite given a synthesis route with >70% accuracy. We employ SHapley Additive exPlanations (SHAP) to uncover key synthesis parameters for >200 zeolite frameworks. We introduce an aggregation approach to extend SHAP to all building units. We demonstrate applications of this approach to phase-selective and intergrowth synthesis. This comprehensive analysis illuminates the synthesis parameters pivotal in driving zeolite crystallization, offering the potential to guide the synthesis of desired zeolites. The dataset is available at https://github.com/eltonpan/zeosyn_dataset.

Synthesis of PHI-type zeolite harmotome using barium as an inorganic structure-directing agent inspired from natural mineral compositions

Zeolites are nanoporous aluminosilicates widely used as commercial adsorbents, heterogeneous catalysts, and ion-exchange materials due to their unique porosity, acidity, and thermal stability. The vast majority of synthetically-realized zeolite structures are prepared under hydrothermal conditions in alkaline media, and often in the presence of an organic structure-directing agent that facilitates the crystallization of diverse porous networks. Due to economic and environmental disadvantages of organic-based syntheses, it is often desirable to produce zeolites in organic-free media using alkali metal ions as the most commonly employed inorganic structure-directing agents (ISDAs). In this study, we were inspired by the elemental compositions of natural zeolite minerals to examine the use of an alkaline earth metal ion as the ISDA to prepare zeolites with the PHI framework type. Two natural minerals exhibiting this crystal structure are phillipsite and harmotome. Both structures contain sodium and potassium as extra-framework cations, but only harmotome contains barium cations. Here we examined how the combination of alkali and alkaline earth ISDAs promote the formation of PHI-type zeolites. Our findings reveal that each isostructure is prepared under different synthesis conditions where simply adding barium to a growth mixture does not always lead to harmotome formation. Harmotome is formed in more dilute and alkaline growth media; however, time-resolved analyses of zeolite crystallization reveal that harmotome can be synthesized at low temperatures (ca. 65 °C) with rates that are 5-times faster than syntheses of phillipsite. This seemingly indicates that barium reduces the energetic barrier for PHI-type zeolite nucleation in ways that are not fully understood. Moreover, harmotome crystals exhibit an average particle size of ca. 60 nm, which is nearly 40-fold smaller than phillipsite crystals prepared under similar conditions. Collectively, these findings identify routes to control crystallization of PHI-type zeolites and may provide a broader strategy for using the composition of natural zeolite minerals to optimize the preparation of synthetic analogues.

Preparation of Biomass-Derived Furfuryl Acetals by Transacetalization Reactions Catalyzed by Nanoporous Aluminosilicates

Preparation of Biomass-Derived Furfuryl Acetals by Transacetalization Reactions Catalyzed by Nanoporous Aluminosilicates

Evolution of Corrosion Products Formed during the Corrosion of MgZr Alloy in Poral Solutions Extracted from Na-Geopolymers Used as Conditioning Matrix for Nuclear Waste.

Geopolymer, a nanoporous aluminosilicate filled with water and ions, has been selected as a potential matrix to encapsulate MgZr alloy fuel cladding. In this study, we investigate the evolution of the corrosion products formed during the corrosion of MgZr in poral solutions extracted from geopolymers with and without NaF as corrosion inhibitor. Using various characterization techniques such as Scanning Electron and Scanning Transmission Electron Microscopies coupled to Energy Dispersive X-ray spectroscopy and Grazing Incidence X-ray Diffraction, we show that the amounts of dissolved silica and fluoride species in solution are the key parameters driving the nature of corrosion products and probably their passivating properties regarding MgZr corrosion.

Atomic and micro‐structure features of nanoporous aluminosilicate glasses from reactive molecular dynamics simulations

AbstractLong‐term chemical durability of borosilicate glasses that makes them a widely accepted form of nuclear waste disposal is achieved through the formation of a porous aluminosilicate gel layer that provides passivity and limits the transport of water to the reaction front. Detailed understanding of the porous silicate gel layer is thus critical in elucidating the corrosion mechanism of these glasses and to design of new glass composition for waste immobilization and other applications. In this paper, we use the diffuse charge reactive potential to generate porous aluminosilicate glass structures with compositions equivalent to the gel layers formed at the glass‐water interface with an aim to understand the processing condition on the microstructure and atomic structure of these systems. We demonstrate the use of the charge scaling techniques is an effective approach to generate these porous structures with controllable pore mophologies. After initial validation of the potentials and calcium aluminosilicate glass structures using neutron diffraction, we created gel structures with compositions similar to well‐known model nuclear waste borosilicate glasses. The porosities and the pore size distribution bear a strong correlation to the processing temperature, as well as to the local atomic structure. Thus, by controlling the processing parameters, the generated porous structures can be customized to closely resemble gel structures due to borosilicate glass corrosion. These results provide insights of the micro‐ and atomic structure features of the porous aluminosilicate glasses and on the optimal procedure to generate porous structures that can be comparable to experimentally observed gel layer structures thus to elaborate on the correlations between the structure and phenomena in glass‐water interactions.

Synthesis and characterization of zeolite Linde Type W and its metal oxide composite Ag-O-LTW used for the decontamination of chemical warfare agent simulant

In this study, we have evaluated the performance of novel adsorbent zeolite Linde Type W and modified LTW with AgO metal oxide composite for the decontamination of chemical warfare agent simulant 2-chloroethylphenylsulphide (CEPS). Zeolites are nanoporous aluminosilicate minerals composed of silicon, aluminum and oxygen framework with cations and water molecules within the pores. The synthesized zeolite LTW and its composites Ag-O-LTW was characterized by XRD, FTIR, SEM-EDS and BET analytical techniques. The decontamination study of CWA simulant, CEPS was monitored by using GC-FID technique. The nanocrystalline zeolite LTW and Ag-O-LTW composites were found powerful adsorbents and showed great decontamination potential toward CWA simulant CEPS. The Ag-O-LTW showed better results (∼98 % decontamination in 7 hours) than LTW zeolite.

Toward the Atomic Scale Simulation of Intricate Acidic Aluminosilicate Catalysts

Zeolites are nanoporous aluminosilicates with well-defined crystalline structures, considered key assets in heterogeneous catalysis, with a broad range of industrial applications. Computational inv...

Environment, Stability and Acidity of External Surface Sites of Silicalite-1 and ZSM-5 Micro and Nano Slabs, Sheets, and Crystals

Zeolites are nanoporous aluminosilicate crystals of prominent fundamental and industrial importance. Among these, ZSM-5 is the most investigated solid that can be obtained in various forms, with so...

Anticorrosion Behavior of Zeolite Coatings Obtained by In Situ Crystallization: A Critical Review.

Zeolites are crystalline nanoporous aluminosilicates. Thanks to their intrinsically nanoporous structure they are widely used as molecular sieves, for exchanging ions, or, also thanks to the high surface area of these structures, for catalytic applications. Furthermore, thanks to their thermal and chemical stability, in recent years zeolite coatings have been evaluated for application as anti-corrosion coatings. The non-toxicity of this class of coatings makes it possible that they will be an environmentally friendly alternative to conventional chromate-based coatings. This article provides a brief review of the anti-corrosion performance of zeolite coatings, applied by direct synthesis technique to several metals and alloys, as discussed in the literature. After a short description of the microstructure and properties of zeolites, the discussion addresses the research activities related to this topic, as reported in the literature. Comparative analysis of literature results supported the dry-gel conversion method as a promising approach that combines a simplified synthesis procedure with anti-corrosion coating performance. Based on these considerations, an evaluation of future trends is discussed along with the final remarks.

Zn Functionalized Nanoporous H-Aluminosilicate used for Production of Bio-fuel Additives

In present work, we are reporting a simple novel one pot, single step, Na- free synthesis method, developed in the lab for the direct production of zinc functionalized nanoporous aluminosilicate (HZnAlSi). For this, we used zinc nitrate hexahydrate (ZnNH) direct in our synthesis procedure, and from the XPS analysis of the resulted material(Fig.1D) showed that zinc is present in the Zn2 oxidation state which supports that Zn is present in the catalytic framework. For catalytic testing, we found HZnAlSi had a potential catalytic application for the industrially important reaction. This catalyst used for the production of biofuel additives with 99.9% glycerol conversation with high selectivity (83.4%) of triacetin under optimum reaction conditions.

Database of Computation-Ready 2D Zeolitic Slabs

Zeolites are nanoporous aluminosilicates widely used in catalysis and separations applications. Though generally formed as 3D crystals, new synthesis techniques have given access to 2D zeolite nanosheets with small diffusion path lengths and accelerated molecular diffusion. Since most previous research has focused on bulk zeolite crystals, there is little understanding of the surface adsorption and diffusion mechanisms likely involved at such length scales and their contributions to the permeability and selectivity of different species. To enable the systematic examination of such surface properties, we constructed a database of more than 800,000 computation-ready 2D zeolite nanosheets from the full range of known zeolite structures in the IZA database of zeolite structure types. The nanosheet surfaces cover a wide range of orientations and were created via the principle of minimizing the number of bonds broken during the termination of a unit cell. The database consists of two sets of nanosheets: one set...

Nanoporous Aluminosilicate-Catalyzed Telescoped Acetalization-Direct Aldol Reactions of Acetals with 1,3-Dicarbonyl Compounds.

Nanoporous aluminosilicate materials, synthesized by an evaporation-induced self-assembly process, catalyze the direct aldol reaction of acyclic acetals with a range of 1,3-dicarbonyl compounds to produce the corresponding aldol addition products in high yield, rather than the expected Knoevenagel elimination products. By carrying out the reaction in the presence of either dimethoxy propane or the corresponding orthoester, it is possible to capitalize on the ability of these aluminosilicate materials to catalyze the corresponding acetalization reaction leading to the development of novel telescoped, acetalization-direct aldol addition reaction protocols.

Liquid-phase solvent-less reactions for value addition of glycerol and phenols over nano porous aluminosilicates

The protocol reports an efficient nano porous solid acid catalyst for the effective conversion of bio-waste product glycerol and phenols into valuable chemicals and fuels through acetalization and alkylation reactions respectively. A novel method was adopted for the direct synthesis of the proton form of Aluminosilicate (HAlSi) from alkali-free gel medium for its ready catalytic applications towards bulky molecular reactions producing chemicals and fuels. In the liquid phase phenol alkylation reactions, the catalyst exhibited 83% conversion with 100% selectivity to the alkylated phenols at solvent-less reaction conditions. The catalyst also exhibited more than 90% conversion in glycerol acetalization reaction to produce mono, di and tri-acetalized esters useful for chemicals and fuel industries. Detailed physicochemical characterization of the synthesized material was conducted by XRD, BET, N2-sorption, NH3 TPD, FTIR, Raman, XPS, SEM, TEM, TG/DTA and Si29 NMR spectroscopic techniques. XPS, FTIR, and NMR results indicated the formation of aluminosilicate chemical structure in the material while TPD confirmed the formation of strong acidity, TEM and sorption studies revealed the formation of ∼50 nm size particles of HAlSi material exhibiting nano porous nature make this nano porous material suitable for acid catalysed bulky molecular transformations exemplified by tert- butylation of phenol and glycerol acetylation. The promising performance of the catalyst towards these reactions was ascribed to the presence of nano size pores in the catalyst and the easy accessibility of the acid sites to the reactants and facile diffusion of the bulky product molecules. The catalyst also exhibited high temperature thermal stability in DT/TGA and structural stability of active sites revealed by stable catalyst performance with reaction cycles. Since, glycerol and phenolic compounds obtain from biomass needs to be addressed for effective value addition, the alkylation and esterification reactions catalysed by present catalyst system provides promising processes to produce valuable chemicals and fuels from low value bio-derivatives.

Template-free synthesis of highly selective amorphous aluminosilicate catalyst for toluene alkylation

In this paper, we report a simple template-free synthetic method that produces amorphous, nanoporous aluminosilicate and highly selective catalyst for toluene alkylation. The structure and composition of the material and its corresponding control material are characterized by various techniques. The material shows excellent catalytic selectivity for alkylation of toluene by tert-butyl alcohol in temperatures between 50–150 °C under atmospheric pressure, producing exclusively 4-tert-butlytoluene (ca. 99%).

Custom catalyst quantifies effect of nanoconfinement

Catalytic materials with nanosized pores and channels play a central role in industrial chemistry. For example, zeolites, a family of nanoporous aluminosilicates, are widely used in petrochemical refining to produce fuels and chemicals. Researchers have long known that confining reagent molecules within nanosized channels of zeolites and other porous materials tends to enhance catalytic reactions. But the complexity of these materials makes it difficult to separate mass transport phenomena from reaction kinetics, which limits basic understanding of these systems. So Wenyu Huang of Iowa State University and Ning Fang of Georgia State University and coworkers designed model catalysts to bypass those difficulties. The materials consist of a solid silica core (100 nm in diameter) decorated with 5-nm-diameter platinum particles; the core is encapsulated within a porous silica shell (120 nm or 80 nm in diameter). The team used those catalysts and a fluorescence microscopy technique that provides single-molecule...

Regulation of sorption processes in natural nanoporous aluminosilicates. 3. Impact of electromagnetic fields on adsorption and desorption of formaldehyde by clinoptilolite

The effect of electromagnetic fields on the adsorption–desorption properties of natural zeolites is a new direction in the theory of physical and chemical processes associated with the surface characteristics of aluminosilicates. The influence of two types of fields, an ultrahigh-frequency electromagnetic field (UHF EMF) and a weak pulsed magnetic field (WPMF) is considered. Modes for treatment of natural zeolite (clinoptilolite) and its activated forms for the most effective sorption of formaldehyde, water, and a mixture thereof were found. It was shown that the preadsorption activation of zeolite in a UHF EMF enhances the selectivity of water vapor sorption, whereas treatment of the sorbent in a WPMF largely affects the selectivity of the absorption of formaldehyde vapors. The decreased desorption of formaldehyde as a result of activation of the mineral in a UHF EMF, as well as complete absence of formaldehyde desorption when a WPMF was used as an activator, was detected.

Zeolite-based copper catalyst for decarboxylative coupling of alkynyl carboxylic acids with aryl iodides

A series of nanoporous aluminosilicate materials (zeolite FAU(Y), LTA(A), and mesoporous Al-SBA-15) was prepared to investigate their catalytic performances in decarboxylative coupling reactions of alkynyl carboxylic acids with aryl iodides. The aluminosilicate frameworks were used for binding Cu(II) ions without coordination by organic ligands. Effects of pore size and Cu(II) content of the aluminosilicates on the catalytic activity and product yield were investigated by varying the solvent, base, and functional groups in the reactants. This catalytic system provided high yields and good selectivity for the desired diaryl alkynes. In addition, the Cu(II)-exchanged zeolite Y catalyst which is NaCuY(0.11) exhibited high recyclability, showing no significant change in catalytic performance after six repetitions.

Regulation of sorption processes in natural nanoporous aluminosilicates. 2. Determination of the ratio between active sites

The ratio of acidic and basic sites on natural aluminosilicates (clinoptilolite, nontronite, and glauconite) and their acidic and basic forms were determined based on the catalytic activity of the samples in the reaction of methylbutynol (MBOH) conversion. Conversion of MBOH took place most fully on the natural zeolite (clinoptilolite). The reagent modification of clinoptilolite(treatment with sulfuric acid and alkali) reduced the ratio of acidic and basic sites. Conversion of MBOH on clay minerals increased in the acid-modified samples and decreased upon the alkali treatment, which corresponds to the change in the ratio of acidic and basic sites in both nontronite and glauconite, but to a greater extent in spherulite-like clay mineral glauconite.