Natural Aluminosilicate Research Articles

Mesoscale Reorganization of the Depolymerized Aluminosilicate into Single-Crystalline Hierarchical Zeolite.

Controllable synthesis of hierarchical zeolites from natural aluminosilicate minerals is considered an efficient and eco-friendly approach for the production of high-performance zeolites, but its synthesis mechanism is still obscure. Herein, we take the synthesis of a single-crystalline hierarchical NaA zeolite using submolten salt depolymerized kaolin (SMS-K) as the sole source of silicon and aluminum via a mesoscale reorganization strategy as an example to elucidate the reorganization process. Comprehensive morphological and structural analyses reveal that sodium-rich voids in SMS-K facilitate concurrent assembly both within the interior and at the interface of the amorphous gel, leading to the formation of numerous nanoparticles with short-range order which assemble into single-crystal nanocube NaA zeolites with intracrystalline mesopores. By harnessing confinement effects, SMS-K modulates the growth of nanoparticle sizes and enhances the intimate interconnection of nanocubes, thereby yielding NaA zeolite aggregates that exhibit hierarchical porosity, encompassing micro-, meso-, and macropores. This study offers the potential for designing and precisely controlling the fabrication of hierarchical zeolites derived from natural minerals.

Facile Synthesis of Zeolite NaX from Natural Attapulgite Clay for Pb2+ Adsorption

The synthesis of zeolites from natural aluminosilicate minerals has drawn extensive attention due to its significant utility in greening the zeolite manufacturing process. In this study, pure-phase NaX zeolite was synthesized via a low-temperature hydrothermal method, utilizing natural, low-quality attapulgite clay as the raw material. Acidified clay was fully activated through alkali fusion at 200 °C, and the impact of alkali fusion temperature, H2O/Na2O ratio, aging temperature, and crystallization time on the resulting crystalline NaX zeolite was investigated. The optimal conditions for obtaining pure NaX zeolite were determined to be alkali melting at 200 °C for 4 h, an H2O/Na2O ratio of 50, aging at 40 °C, and a crystallization period of 11 h at 90 °C. With a large BET surface area of 328.43 m2/g, the obtained NaX zeolite was used to adsorb Pb2+ from wastewater with a removal rate of 95%. This research provides a valuable method for the extensive and efficient utilization of low-grade natural attapulgite clay. Moreover, this is the first report on the synthesis of pure-phase NaX zeolite using only low-quality natural attapulgite clay as raw material through an atmospheric pressure water bath method.

Impurity Ions Mn<sup>2+</sup> and Fe<sup>3+</sup> as Paired Spin Labels for the Study of Structural Transformations in Phyllosilicates by the ESR Method

Impurity paramagnetic ions Mn2+ and high spin Fe3+ (S = 5/2) are shown to be very informative “paired spin labels” to investigate structural transformations in natural aluminosilicate clay minerals by ESR spectroscopy. Second derivative ESR (SD ESR) enables to detect minor narrow lines of the ions against the background of intense broad lines of other paramagnetic impurities. Complex SD ESR spectra of the ions are explained by the Jahn-Teller effect and hyperfine interactions with OH-groups. SD ESR spectra before and after heating (620°C and 900°C) proved transformations of octahedral crystal cells accompanied by the loss of the OH-groups, displacement of the ions to equivalent positions.

Erratum to: Patterns of the Adsorption of Proteins of Different Molecular Weights on Natural Aluminosilicate Nanotubes

Erratum to: Patterns of the Adsorption of Proteins of Different Molecular Weights on Natural Aluminosilicate Nanotubes

Experimental Investigation on Concrete with Zeolite Powder, Silica Fume and Cashew Nut Shell Ash

Abstract: This experimental investigation explores the impact of incorporating zeolite powder as a partial replacement for fine aggregate, along with silica fume and cashew nut shell ash (CNSA) as partial replacements for cement in concrete. Zeolite, a natural aluminosilicate mineral, is known for its pozzolanic properties, which can enhance the mechanical and durability characteristics of concrete. Silica fume, a byproduct of silicon and ferrosilicon alloy production, is renowned for its high silica content and fineness, contributing to the strength and density of concrete. Cashew nut shell ash, an agricultural waste product, offers a sustainable alternative to traditional cementitious materials, potentially reducing the environmental footprint of concrete production. This experimental study investigated the effects of partially replacing fine aggregate with zeolite powder (5%,10% and 15%) and cement with silica fume (3%,6%,9%,12% and 15%) and cashew nut shell ash (5%,7.5%,10%,12.5%,15% and 17.5%) on the properties of concrete. This study underscores the viability of using zeolite powder, silica fume, and CNSA in sustainable concrete production, contributing to the development of more environmentally friendly construction materials. Further research is recommended to explore the long-term performance and environmental benefits of these alternative materials in concrete applications.

The development of a dexamethasone challenge model for evaluating feed additives in sheep.

To develop an accessible ruminant immune challenge model for rapid in vivo assessments of feed additives. 60 hair-breed ram lambs. Sheep were randomly assigned to 1 of 4 treatments: treatment 1, not immunosuppressed, control fed (n = 12); treatment 2, immunosuppressed, supplemented with a yeast and botanical extract (n = 18); treatment 3, immunosuppressed, supplemented with a blend of natural aluminosilicates and yeast components (n = 18); and treatment 4, immunosuppressed, control fed (n = 12). Twice-daily injections of dexamethasone (Dex; 0.1 mg/kg bodyweight, SC) were used to induce immunosuppression throughout the study (from September 25, 2020, to November 2, 2020). All sheep were immunized with keyhole limpet hemocyanin (KLH) on days 0 and 14 and injected with heat-aggregated KLH, ID, to induce a skin induration on day 15. Measurements included body weight (BW), average daily gain (ADG), CBC, and skin induration diameter. Dex treatment resulted in reduced BW and ADG that was not mitigated by either feed additive. Dex reduced lymphocyte percentage, RBC count, hemoglobin, hematocrit, and skin induration diameter and increased concentrations of granulocytes and granulocyte percentage. Effects on hematocrit, hemoglobin, RBC, and skin induration diameter were mitigated with the addition of feed additives. The described model is a tool to evaluate the ability of feed additives to mitigate the immunosuppressive effects of Dex.

Effect of the Acidic Treatment on the Catalitic Properties of Natural Aluminosilicates in Glycerol Acetylation

Effect of the Acidic Treatment on the Catalitic Properties of Natural Aluminosilicates in Glycerol Acetylation

Preparation of novel silica-clay mineral aerogel nanocomposites with outstanding thermal insulation performance

Monolithic silica-based aerogels, produced with tetraethoxysilane (TEOS), reinforced with aramid fibers and incorporating aluminosilicates were prepared for the first time. The nanocomposites were obtained by varying the amount and type of aramid fibers and replacing a part of the synthetic Si (up to 35 wt% of Si) of TEOS by natural aluminosilicates, kaolin and palygorskite. The effects of the type and amount of both fiber and mineral in the materials key properties were investigated. Most samples displayed very low volumetric shrinkages during ambient drying (<5%), high porosity (∼90%), and low bulk densities, down to 120 kg m−3. Composites with both minerals exhibited superinsulating thermal performance, with thermal conductivity reaching values as low as 22 mW m−1 K−1, while also showing excellent thermal stability. The mechanical properties of the designed clay mineral-silica aerogels can be tailored, since the addition of short length fibers (Kevlar pulp) produces stiffer composites, while the longer fibers (Teijinconex) lead to more flexible ones.

STUDY OF THE INFLUENCE OF THE MINERAL COMPOSITION OF ROCKS AND VARIOUS DEPOSITS ON SOIL PRODUCTIVITY

The article indicate the results of investigate on treatment of the ecological state of the soil. It is shown that carrying out various agrotechnical and reclamation measures improves ecological situation agricultural land and contributes to obtaining environmentally friendly and plentiful harvests , however, much attention is paid to the use of mineral fertilizers. It is noted that, applied in large quantities, mineral fertilizers cause great harm to the ecological state of the soil. An overview of various soil additive improvers used as soil leavening agents, such as coarse sand, fine, gravel and expanded clay, broken red brick, perlite, vermiculite, bentonite clay, zeolites, and other aluminosilicates. Whereas that at present, environmentally friendly natural aluminosilicates are used quite often as a reagent that improves the ecological state of the soil. Solid rocks - aluminosilicates, most suitable as an additional source of useful minerals such as calcium, magnesium and potassium, etc., while reducing the swelling capacity of the soil, improving the water capacity and absorption capacity and able to weaken the transition of mineral x fertilizer into a state of difficult to digest soil oh.

Patterns of the Adsorption of Proteins of Different Molecular Weights on Natural Aluminosilicate Nanotubes

Patterns of the Adsorption of Proteins of Different Molecular Weights on Natural Aluminosilicate Nanotubes

Sorption properties of silicate materials from straw rice and vermiculites

A number of silicate and aluminosilicate sorption materials have been synthesized using rice straw as a silicon source. The dependence of sorption properties with respect to methylene blue, as well as density and moisture capacity on the composition is investigated. It is shown that the sorption capacity of silicate materials from vegetable raw materials is several times greater than that of natural aluminosilicates – vermiculite and materials based on it obtained by chemical modification. The presence of an organic component in the composition of the obtained biogenic materials contributes to a higher sorption capacity. The density and moisture capacity of the synthesized materials are determined.

Physico-chemical properties of Russian natural aluminosilicates for purification of aqueous environment

The paper analyses and compares the physico-chemical properties of aluminosilicate green clay and bentonite and diatomite from the Russian deposits. The research determines specific surface area and the morphological features of aluminosilicates, their pore sizes, and pore distribution by volume. The surface of the green clay includes silicon and aluminum oxides, montmorillonite, kaolinite, impurities of pyrite, saponite, micas, and hydrosludes. It also contains a lot of rounded particles with a diameter of 1-2 μm. According to the research, adsorption isotherms for mesoporous green clay samples belong to type IV; the samples of bentonite and diatomite (Middle Volga regions of Russia) belong to type II. They characterize the monolayer-multilayer concentration of solution components on macroporous bodies. Also the research revealed a sufficiently high amount of adsorbate (31 ml • g-1) to cover the surface of diatomite (Ulyanovsk region, Russia) with a monomolecular layer. The source minerals of diatomite are montmorillonite and muscovite. The study of adsorption and desorption branches for a bentonite sample (Samara region, Russia) indicates the processes asymmetry. Hence, we compared the ability to adsorb iron (II) and lead ions from aqueous systems using green clay extracted in different years (2017 and 2023).

Multiphase synergistic immobilization of complex trialkyl phosphine oxide end-waste into an iron-containing aluminosilicate glass-ceramic

The objective of this study was to address the challenges associated with complex TRPO waste, by utilizing a natural aluminosilicate material to produce glass-ceramic waste forms. When the simulated waste content was below 30 wt.%, glassy waste forms were successfully obtained. Ce and Fe played crucial roles in the formation of Si–O–Ce bonds and [FeO4]-tetrahedra in the glass network, which effectively immobilized other waste elements. However, when the waste content exceeded 30 wt.%, the waste was incorporated into feldspar, iron-manganese crystals, fluorite ceramic, and glass. This combination of ceramic and glass matrices synergistically immobilized the waste, resulting in excellent mechanical performance and chemical durability. The leaching rates of LRCe and LRNd were remarkably low around ∼10−6 to 10−7 g m−2 d−1, after 42 d. Furthermore, the study also investigated the role of multi-valence elements, such as Ce, Fe, and Mn, in the formation of iron-containing aluminosilicate glass-ceramics. The findings offer a novel approach to effectively immobilize complex nuclear waste.

Synthesis and application of Pt-containing catalysts based on mordenite zeolite and natural halloysite nanotubes in the gas-phase isomerization of C-8 aromatic fraction

The MOR-type zeolite was synthesized by a template-free method using natural aluminosilicate halloysite nanotubes (HNT) as a hard template and a source of aluminum and silicon. Samples were studied using a complex of physicochemical methods of analysis: XRD, TEM, N2 physisorption, NH3-TPD and XRF. Specific BET surface area of MOR prepared using HNT is 306 m2/g, mesopores in the MOR:HNT accounted for 30 % of the total pore volume. Based on the synthesized materials (MOR, MOR:HNT and MOR + HNT), Pt-containing catalysts were prepared. The catalysts were investigated in the gas-phase isomerization of C-8 aromatic fraction in a temperature range of 360–420 °C, varying LHSV from 2 to 6 h−1, at H2 pressure of 1 MPa and hydrogen/feedstock volume ratio of 900 nl/l. The prepared catalysts demonstrated strong activity in ethylbenzene transformation (more than 95 %), while providing a high yield of p-xylene (more than 95 % of thermodynamic value).

Research Trends in the Mechanoactivation of Clay Minerals Used in Obtaining Geopolymers

The article is an attempt to review scientific achievements in the field of obtaining aluminosilicate geopolymers and current research trends in the field of mechanical treatment (mechanical activation or mechanoactivation, as the term is used in the article) of their predecessors. A geopolymer, also referred to in the literature as geopolymer resin and geopolymer cement, is a mineral binder resulting from geopolymerization, the main step of which is the polymerization (or polycondensation) of precursors in an alkaline or acidic medium. This review focuses on geopolymers whose precursors are natural aluminosilicates, i.e., clay minerals, because, firstly, clay minerals are widespread and available worldwide, and secondly, geopolymers based on heat-treated kaolinite (or metakaolin) have a number of advantages that make kaolinite attractive for further study in terms of reducing energy consumption and carbon footprint in their manufacturing. On the other hand, the review considers the potential of mechanoactivation of clay minerals in an air medium and establishes that mechanoactivated kaolin clays have the potential to replace metakaolin.

Improving the heat transfer characteristics of miniature two-phase thermosyphons with nanofluids based on Ukrainian natural alumosilicates

In order to improve the heat transfer characteristics of miniature thermosyphons, a study of the processes of heat transfer by them using water and nanofluids as heat carriers was carried out. A water mixture based on nanoparticles of Ukrainian natural aluminosilicate - attapulgite with the addition of 0.1 % carbon nanotubes was used as nanofluids. The data of the study of the maximum heat flow and the minimum thermal resistance of copper thermosyphons with an internal diameter of 5 mm and a length of 700 mm are presented. Orientation of thermosyphons in space: vertical. The length of the heating zone varied from 50 mm to 200 mm, with the same amount of heat-carrier. The fill factor varied from 0.44 to 1.93. A comparison was performed of the heat transfer capabilities of thermosyphons with water and with a nanofluid with a mass concentration of 0.5 %. It has been shown that nanofluid thermosyphons transmit 53 % more heat flow compared to water, and thermal resistances are reduced by 25 %. The influence of the concentration of nanoparticles on the heat transfer characteristics of thermosyphons is shown. Nanofluids with concentrations (0.1 %, 0.5 %, 0.7 %) showed the same level of thermal resistances, with an increase in maximum heat flows compared to distilled water. Thus, when compared with the lowest concentration (0.1 %), the use of 0.5 % nanofluid gives an advantage of up to 40 %, and 0.7 % – an advantage of up to 51 %. This is explained by the appearance of a specific porous structure of anisometric nanoparticles on the heating surface, which contributes to the appearance of additional centers of vaporization during boiling and improves the heat transfer characteristics of thermosyphons. Thus, the use of such thermosyphons with nanofluids when cooling elements of electronic equipment could improve their functional characteristics

Characterization of recrystallized natural aluminosilicate

Characterization of recrystallized natural aluminosilicate

Hierarchically porous bioceramics based on geopolymer-hydroxyapatite composite as a novel biomaterial: Structure, mechanical properties and biocompatibility evaluation

In this study, open-cell porous bioceramics based on geopolymers were synthesized by the replica technique. The composition consisted of a mixture of metakaolin (MK) and hydroxyapatite (HA) that combined are suitable for application in bone tissue engineering. Metakaolin is a cheap natural aluminosilicate known for its mechanical properties, while hydroxyapatite stands out for its biocompatibility due to the chemical structure similar to the bone matrix. After undergoing heat treatment (HT), the geopolymer-hydroxyapatite (GMK-HA) synthesized materials, referred to as GMK-HA-HT, presented pores in the range from 1 to 5 mm. In the compressive strength tests, they exhibited values between 1.18 and 2.9 MPa. These ranges of values signify a proper balance between mechanical strength and porosity. X-ray diffraction analysis showed phosphate and/or calcium crystalline phases in all heat-treated samples, indicating HA's successful incorporation in the geopolymer structure. In vitro tests using human adipose-derived mesenchymal stem cells (ADSCs) were conducted to evaluate the biocompatibility of the synthesized materials. The extracts obtained from the GMK-HA-HT were found to be non-cytotoxic. ADSCs in contact with extracts have no morphological changes and when cultured on the GMK-HA-HT surface, the cells interacted with the scaffold and formed a monolayer. Here, for the first time, we provide insights into this new class of materials as a promising biomaterial candidate which could be associated with ADSCs to promote bone healing.

Fe- and Cu–Zn-Containing Catalysts Based on Natural Aluminosilicate Nanotubes and Zeolite H-ZSM-5 in the Hydrogenation of Carbon Dioxide

Iron- and Cu–Zn-containing carbon dioxide hydrogenation catalysts based on natural aluminosilicate nanotubes and zeolite H-ZSM-5 are synthesized. Their textural and acidic properties are studied via low-temperature nitrogen adsorption–desorption, temperature-programmed desorption of ammonia, temperature-programmed reduction of hydrogen, and elemental analysis. The effect the temperatures of the reaction have on the conversion of CO2 and distribution of its product is studied. Catalysts based on aluminosilicate halloysite nanotubes exhibit methanol and С2–С4 hydrocarbon selectivities of 88 and 16%, respectively.

Fe- and Cu–Zn-Containing Catalysts Based on Natural Aluminosilicate Nanotubes and Zeolite H-ZSM-5 in the Hydrogenation of Carbon Dioxide

Fe- and Cu–Zn-Containing Catalysts Based on Natural Aluminosilicate Nanotubes and Zeolite H-ZSM-5 in the Hydrogenation of Carbon Dioxide