Natural Aluminosilicate Research Articles

Mesoporogen-free synthesis of hierarchical sodalite as a solid base catalyst from sub-molten salt-activated aluminosilicate

A rapid and environmentally friendly approach to synthesize hierarchical sodalite from natural aluminosilicate mineral without the involvement of any mesoporogen or post-synthesis treatment was developed. This strategy involves three important steps: the first is the depolymerization of an aluminosilicate mineral into highly reactive silicon and aluminum species with ideal meso-scale structures through activation of a sub-molten salt. The second step is the hydrolysis and condensation of the activated aluminosilicate mineral into zeolitic precursors that also have a meso-scale structure. The third is the rapid zeolitization of the zeolitic precursors through the reversed crystal growth route at room temperature and ambient pressure to form hierarchical sodalite. The physicochemical properties of the as-synthesized sodalite were systematically characterized, and the formation mechanism of the hierarchical pore structure was discussed. When used as a solid base catalyst for Knoevenagel condensation, the as-synthesized sodalite and its potassium ion-exchanged product with hierarchical micro–meso–macroporous structure both exhibited high catalytic activity and product selectivity.

МУЛЛИТ И ЕГО ИЗОМОРФНЫЕ ЗАМЕЩЕНИЯ ОБЗОР

Рассмотрена фазовая диаграмма системы SiO2-Al2O3. Представлен обзор методов синтеза муллита, в т. ч., обжигом природных алюмосиликатов, из расплава методом Чохральского, методом Вернейля из геля, и твердофазным методом из шихты стехиометрического состава. По литературным данным установлено, что параметры ромбической решетки и габитус кристаллов муллита напрямую зависят от величины соотношения алюминия и кремния в исходной шихте, содержания примесей, способа термической обработки и формы введения в шихту исходных компонентов. На размер кристаллов муллита влияет наличие фторида алюминия в шихте, что при определенных соотношениях позволяет получать конечный продукт в виде вискерсов. Рассмотрено воздействие минерализаторов на выход муллита: фториды щелочных металлов его уменьшают, а сульфаты и хлориды увеличивают, а также влияют на вязкость и структуру расплава. С этой целью рассмотрены различные добавки и их влияние на характер синтеза, структуру и свойства. Выявлены структурные особенности кристаллической решетки муллита, влияющие на изоморфные замещения. Рассмотрена возможность получения изоморфно замещенных разновидностей муллитов. В работе приведены оптические характеристики изоморфно замещенных муллитов, содержащих d-элементы.

Organic-Inorganic Hybrid Thin Films Fabricated by Layer-by-Layer Assembly of the Phosphorylated Cellulose Nanocrystal and Imogolite Nanotubes.

Phosphorylated cellulose nanocrystal (P-CNC)/imogolite nanotube (natural aluminosilicate nanotube) hybrid thin films were fabricated by spin-assisted layer-by-layer assembly. Phosphorylation of CNC with diammonium hydrogen phosphate ((NH4)2HPO4) was carried out to introduce phosphate groups on the CNC surface for enhanced interaction with imogolite. Structure of the P-CNC/imogolite thin film was characterized by atomic force microscopy, scanning electron microscopy, X-ray diffraction (XRD), and grazing incidence wide-angle XRD. The film thickness increased linearly with the increment of the P-CNC/imogolite bilayer. Benefitting from the strong affinity between the phosphate group of the P-CNC and the Al-OH group of imogolite, the P-CNC/imogolite thin films were quite stable in water within a wide range of pH values, compared with the deterioration of the CNC/imogolite film under same soaking conditions.

Kinetic Study of Seed-Assisted Crystallization of ZSM-5 Zeolite in an OSDA-Free System Using a Natural Aluminosilicate as Starting Source

We studied the crystallization of ZSM-5 zeolite by hydrothermal treatment in the absence of organic structure directing agents (OSDA) at 170, 180, and 190 °C, using Perlite as a natural source of S...

Interaction of Rh(III) with Humic Acids and Components of Natural Adsorption Phases

To study the migration and accumulation of Rh(III) in natural systems, we have synthesized complexes of Rh(III) and fulvic acids (FA), which are dominant organic compounds of natural waters. The composition of rhodium hydroxofulvate complexes is determined at pH 7.0, and the stability constant of these complexes is calculated. Data are obtained on interaction of FA and Rh(III) hydroxofulvate complexes with components of naturally occurring reactive barriers (ferrihydrite, quartzite, clay shale, and natural aluminosilicate suspensions) at pH 4.0–8.0. The adsorption behavior of FA and rhodium fulvate complexes at the sorbents was determined to be analogous.

The Effect of a Pulsed Magnetic Field on the Hydration Properties of Clinoptilolite and Glauconite

The effect of a weak pulsed magnetic field (WPMF) on the hydration properties of natural aluminosilicates of different structures (clinoptilolite and glauconite) is established. Isotherms of water adsorption are analyzed using the BET equation and a more considerable decrease in the limiting capacity of a monolayer on clinoptilolite is determined as compared to that on glauconite (more than threefold), as is the corresponding decrease in the specific surface area of clinoptilolite, which is confirmed by the data of IR-spectral analysis.

Effective sorbents based on plasma-modified aluminosilicate minerals

The construction industry requires the emergence of new promising technologies. This stimulates the creation of modern building materials, which have an expanded set of functional properties. Such materials ensure ecological compatibility of the rooms of constructed buildings and structures. One of the main sources of air pollution is building materials, structures and products. They account for up to 80% of the chemicals found in the air of the rooms in operation. The development of materials capable of absorbing toxic substances is a promising direction in the construction industry. Absorption of toxic products from the air can be achieved by the use of effective, obtainable sorbents. Among such sorbents is a group of natural zeolite-containing minerals. The article presents the results of a study to determine the activity and sorption capacity of modified zeolites of the Hotynets deposit, bentonites of the Tarasovskoye deposit. A comparative evaluation of the ways of sorbent activation is given. The mineralogical and chemical composition of the investigated zeolites, the results of the action of a low-temperature nonequilibrium plasma on the structure of natural aluminosilicates are presented. As a result of the action of a low-temperature nonequilibrium plasma, the sorption capacity of both zeolites and bentonites increased. Modification of low-temperature non-equilibrium plasma maximizes the efficiency of natural zeolite-containing rocks, which makes it possible to expand their functional capabilities. The use of low-temperature nonequilibrium plasma is an economically and environmentally beneficial method.

NATURAL CLINOPTILOLITE ANCHORED CHLORIDES OF 3D METALS IN THE REACTION OF LOW-TEMPERATURE SULFUR DIOXIDE OXIDATION WITH AIR OXYGEN

Such adsorbents as natural aluminosilicates and activated coal and such chemisorbents as transition metal oxides are commonly used for cleaning gas emissions from sulfur dioxide. The main disadvantage of the latters except for manganese oxides is that high temperatures (up to 800 °C) are needed for the reaction proceeding. However sulfur dioxide can be oxidized to H 2 SO 4 in conformity with complicated mechanisms in aqueous solutions of coordination compounds of copper(II,III), iron(II,III), manganese(II) and cobalt(II) at ambient temperature. Three types of mechanisms of interaction between sulfur dioxide and air oxygen can be considered as most probable: the chain-radical mechanism with single-electron transfer, the non-radical mechanism with two-electron transfer, and the combined mechanism having some elements of two above-mentioned mechanisms. We studied the reaction of sulfur dioxide oxidation by air oxygen over natural clinoptilolite anchored chlorides of 3d metals (MCl2/NCLI where М = Cu2+, Co2+, Mn2+, and Cd2+). It has been found that the amounts of sulfur dioxide reacted (Qexp) at all CMCl2 are far more, than Qexp in the case of pure N-CLI. That is 3d metal chlorides can affect the reaction of sulfur dioxide oxidation with air oxygen. However the mechanisms of their action depend on the nature of the metal ion and its concentration. This phenomenon can be seen from the values of Qexp, tMPC (a time of protective action, i.e. a period of time from experiment beginning up to the moment when C fSO2 achieves its maximum permissible concentration (MPC), 10 mg/m3), and t1/2 (a half-conversion time, i.e.a period of time from experiment beginning up to the moment when C fSO2b ecame equal to 0.5C in SO2 ) . For instance, at CMCl2 = 2.9×10-5 mol/g, Qexp, tMPC and t1/2 decrease in the order Mn(ІІ)> Cu(ІІ) > Cd(ІІ) > Co(ІІ), whereas at CMCl2 = 11.7 ∙10-5 mol/g, the order changes as follows: Cu(ІІ) > Co(ІІ) > Cd(ІІ) > Mn(ІІ). Thus, comparing the results of our experiments and the data for resolved 3d metal chlorides reported in literature, a certain similarity can be traced.

Water vapor interaction with borosilicate glass

Hydration of borosilicate glass (Corning Pyrex glass) in isotopic water H218O vapor was performed at different temperatures. The depth distributions of 1H and 18O in the borosilicate glass measured by the Time-of-Flight Secondary Ion Mass-Spectrometry (TOF-SIMS) were found to be drastically different. The activation energies for the 18O diffusion and for the glass hydrogenation were measured experimentally. The depth distribution of the 18O isotope was described well by the complementary error function, whereas the depth distribution of hydrogen represented the so-called “S-curve”. A similar hydrogen distribution was observed earlier in hydrated natural aluminosilicate glasses (obsidians). This led us to the conclusion that the hydrogenated layer was formed due to a solid state chemical reaction between protons and the glass network. The protons were the result of another solid state chemical reaction between the absorbed water molecules and glass network occurring in a top surface layer (<30 nm).

Influence of the Type of Catalysts on the Formation of a Superhydrophobic Carbon Nanomaterial in Hydrocarbon Flames

The authors present results of synthesis of superhydrophobic soot in flames of various hydrocarbons (methane, propane, butane, and polyethylene waste) using metallic catalysts of the gauze type from nichrome wire and of the honeycomb type from nickel plates, and also natural aluminosilicates. An analysis of hydrophobic characteristics of the obtained samples of soot has shown a substantial influence of the catalysts on its hydrophobic properties. The best samples of soot with a wetting angle larger than 160° were obtained during the combustion of gaseous hydrocarbons with the use of the honeycomb-type nickel catalyst. Soot samples obtained during the combustion of propane with a honeycomb-type nickel catalyst had a wetting angle within 160–165°, suggesting the presence of superhydrophobic properties in the soot. These samples were characterized by the large degree of graphitization (≈20%), which is due to the influence of metallic nickel on the structure of formed soot particles.

Catalytic Compositions Based on Chlorides of d Metals and Natural Aluminosilicates for the Low-Temperature Sulfur Dioxide Oxidation with Air Oxygen

Catalytic Compositions Based on Chlorides of d Metals and Natural Aluminosilicates for the Low-Temperature Sulfur Dioxide Oxidation with Air Oxygen

An Active Corrosion Inhibition Coating of Two Pack Epoxy Polyamide System using Halloysite Nanocontainer

This work deals with encapsulation of corrosion inhibitor in inorganic nanocontainer and the investigation of the corrosion inhibition rate from the nanocontainer. Halloysite nanotubes were used as inorganic nanocontainer for encapsulating the active corrosion inhibitor. These cylindrical shaped halloysite nanotubes are a natural aluminosilicate, which possesses similar chemical composition as that of pure kaolin clay. The structural morphology and functional organic attachments to the halloysite nanocontainers were determined by using TEM and FTIR analysis. It is found that, halloysite nanocontainers are having external and internal lumen is in nanosize (diameter) and length up to several micrometers. A maximum benzotriazole loading up to 10% (by weight) was achieved in inorganic nanotube of 50 nm external diameters and lumen of 15 nm. The release of corrosion inhibitor was carried out for 18 h at different pH ranging from 3 to 10. The weight percent of the benzotriazole encapsulated halloysite nanocontainer was varied from 2 to 10 and then dispersed in 2K clear coat epoxy-polyamide. The self-healing anticorrosion performance of these nanocomposites coating was tested with help of electrochemical impendence spectroscopy (EIS) and Tafel plot. From Tafel plots it is found that the Icorr value decreases to 1.018E–7A/cm2 from 0.018 A/cm2, when coating was applied with 2 wt % nanocontainer.

Ways to Improve the Ecological Safety of the Livestock Sector under Associative Mycotoxicoses

The problem of accumulation in the animal feed of a large number of mold fungi and their metabolites - mycotoxins - has become very important in recent years. As an effective method of detoxification therapy, enterosorption is proposed to be used with the help of natural aluminosilicate minerals and preparations based on them, which possess sorption, antitoxic, hepatoprotective and antioxidant properties. Using an analog method, four groups of calves were formed, taking into account age and body weight. Intergroup differences consisted of the prescribed medicinal preparations, which were added to the diet of the main ration at a dose of 0,3 g / kg of body weight for 21 days. It has been experimentally proved that preparations on the background of feed of calves, that were fed with mycotoxins and spores of fungi, have a pronounced preventive effect in associative mycotoxicoses. Normalization of metabolic processes in the liver was noted, which was manifested by an increase in the level of total protein in the experimental groups by 24,4%, 18,1% and 19,4%. The level of alanine aminotransferase decreased by 15,2%, 12,3% and 11,3%, tha level of aspartate aminotransferase decreased by 24,2%, 20,9% and 18,7%. At the same time, preparations helped to reduce the endogenous intoxication of the calves' organism and reduce the accumulation in the blood of middle-mass molecules (MMM) by 36,6%, 22,3% and 21,3%.

Влияние различных механизмов нагрева слоистого алюмосиликата на сорбционные процессы. Сообщение 1. Сорбция воды при тепловом и электромагнитном (СВЧ) нагреве монтмориллонита

Используется различный механизм нагрева монтмориллонита для повышения его адсорбционной способности: быстрый объёмный нагрев образца электромагнитным излучением СВЧ дециметрового диапазона с частотой 2,45 ГГц и традиционный поверхностный нагрев. Проведены дериватографические исследования, исследована кинетика сорбции воды, определена лимитирующая стадия процесса адсорбции молекул воды. Установлено значительное возрастание сорбционной ёмкости образца, предварительно обработанного в электромагнитном поле СВЧ, как результат его более глубокой дегидратации, и, как следствие, вероятного усиления кислотности его поверхности.

Synthesis and characterisation of zeolite-A and Zn-exchanged zeolite-A based on natural aluminosilicates and their potential applications

Zeolites have been hydrothermally synthesized using alumina and silica based deposits (kaolin, bauxite, silica and feldspar) sampled from three regions in Ghana and the chemical compositions of the...

Modification of alternative additives and their effect on the rubber properties

The present paper deals with a targeted modification of two kinds of alternative additives - waste from glass production and natural mineral filler and explores their effect on the properties of polymeric materials. In the function of first alternative filler was used sludge from weighing the ingredients of glass batch in the glass production. The second used was natural aluminosilicate material based on zeolite (clinoptilolite). These alternative fillers have been modified in order to increase its efficiency, using the silanes: 3-aminopropyl-triethoxysilane, bis(triethoxysilyl)propyl-tetrasulfide and 3-(triethoxysilyl)propyl-methacrylate. In the case of alternative filler based on zeolite the influence of silanization conditions on the filler efficiency have been also studied. Prepared modified fillers were mixed into rubber compounds as partial replacement of commonly used filler – carbon black. The influence of prepared fillers on rheology and curing characteristics of rubber compounds and also on physical and mechanical properties of vulcanizates has been studied. Obtained results of measured characteristics of polymeric systems containing prepared alternative fillers were compared with the results obtained in the case of reference rubber compound with a commertially used filler – carbon black.

Determination of the Parameters of Selective 137Cs Sorption onto Natural and Ferrocyanide-Modified Glauconite and Clinoptilolite

The effect exerted by surface modification of natural aluminosilicates, glauconite and clinoptilolite, with ferrocyanides on the parameters of selective 137Cs sorption was studied. The modification leads to an increase in the specific sorption and in the radiocesium interception potential in the presence of potassium, RIP(K). RIP(K) of the modified sorbents NPF-Gl and NPF-Cl was 6.1 × 105 and 5.0 × 106 mmol kg–1, and the specific sorption capacity, 138 ± 14 and 136 ± 12 mg g–1, respectively. The regular trends in variation of the 137Cs distribution coefficients in sorption onto the natural and modified sorbents at K+ and Са2+ concentrations ranging from 10–4 to 2.0 M were found. The modified sorbents exhibit high specificity to 137Cs in a wide range of Ca and K concentrations in the solutions.

Enhancing the reactivity of aluminosilicate materials toward geopolymer synthesis

Geopolymers are alternative materials to portland cement, obtained by alkaline activation of aluminosilicates. They exhibit excellent properties and a wide range of potential applications in the field of civil engineering. Several natural aluminosilicates and industrial by-products can be used for geopolymer synthesis, but a lot of starting materials have the disadvantage of poor reactivity and low strength development. This paper presents a comprehensive review of the main methods used to alter the reactivity of aluminosilicate materials for geopolymer synthesis, as reported recently in the literature. The methods consist of mechanical, thermal, physical separation and chemical activation, of which mechanical activation is the most commonly employed technique. The reactivity of the activated aluminosilicate materials is mainly related to the activation method and the treatment parameters. Chemical activation by alkaline fusion is a promising method allowing preparation of one-part geopolymer materials, an alternative class of geopolymeric binders. However, the resulting alkaline-fused geopolymer products are vulnerable to attack by excessive alkalis.

Adsorption of Nickel(II) and Copper(II) Ions by Modified Aluminosilicates

According to X-ray phase analysis, modification of natural aluminosilicates with hydrogen chloride is accompanied by the destruction of the main component—calcium heulandite—the content of which decreases from 64.3 to 42.9%. An increase in temperature during the modification process contributes to the packing of the cristobalite structure, which positively affects the adsorption properties of the materials. In the process of activation of aluminosilicates by hydrogen chloride, their texture characteristics change: the specific surface (from 33 to 75 m2/g) and the specific pore volume (from 0.015 to 0.036 cm3/g) increase more than double. The average pore size is reduced from 1.8 to 1.6 nm. The result of such changes is an increase in the adsorption capacity. Adsorption of nickel(II) and copper(II) ions on modified aluminosilicates is most adequately described by the Langmuir adsorption model.

Synthesis of a nanocomposite based on polyethylene and modified vermiculite

A composite of polyethylene and vermiculite, a natural aluminosilicate, has been prepared by treating vermiculite with a concentrated polyethylene solution in xylene. Varying the concentration of the polyethylene solution, we obtained materials with various compositions, which were then modified by heat treatment and chemical means (by HCl solution, followed by precipitation of metal ions). We have determined the elemental composition of the composite materials, obtained their IR spectra and X-ray diffraction patterns, and evaluated their surface properties and sorption capacity for organic dyes and oil products. The chemical modification of the composite materials increases their dye sorption capacity, which correlates with the observed changes in their specific surface area and specific pore volume.