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Liquid fuel production from biomass-derived molecules has received great attention due to the diminished fossil fuel reserves, growing energy demand, and the necessity of CO2 emission reduction. The deoxygenation of oils and fatty acids is a promising process to obtain "green" diesel. Herein, we report the results of the study of the deoxygenation of stearic acid to alkanes as a model reaction. Series of Ni-supported on schungite were obtained by precipitation in subcritical water (hydrothermal deposition) and for comparison via wetness impregnation followed, in both cases, by calcination at 500 °C and a reduction in H2 at 300 °C. The catalyst obtained via hydrothermal synthesis showed a three-fold higher specific surface area with a four-fold higher active phase dispersion compared to the catalysts synthesized via conventional impregnation. The catalysts were tested in stearic acid deoxygenation in supercritical n-hexane as the solvent. Under optimized process conditions (temperature of 280 °C, hydrogen partial pressure of 1.5 MPa, and 13.2 mol of stearic acid per mol of Ni), a close to 100% yield of C10–C18 alkanes, containing over 70 wt.% of targeted n-heptadecane, was obtained after 60 min of reaction. [ABSTRACT FROM AUTHOR]

The possibility of obtaining a foamed aluminosilicate product for construction purposes from the ashes of a coal-fired power plant, cullet, and silicon carbide is shown. The physical and mechanical properties of the obtained foamed aluminosilicates have been studied. The temperature regime and the optimal ratio of components for the production of foamed aluminosilicate were determined. It has been established that in terms of strength characteristics, the obtained aluminosilicate is not inferior to known porous building materials. In terms of thermal conductivity, water absorption, and frost resistance, it surpasses them. It is established that the use of ash with a fraction of more than 300 μm does not lead to pore formation in the system. A distinctive feature of the obtained foamed aluminosilicate product is the closure of the pores, which has a positive effect on its performance. [ABSTRACT FROM AUTHOR]

The processing of lignocellulose wastes is one of the urgent tasks in modern society. These wastes can be effectively used for the production of heat, electricity, fuels, and valuable chemicals. Catalytic pyrolysis can be considered the most effective way to convert waste into valuable products. In this work, the investigation of the pyrolysis process of the birch and pine sawdust was carried out in the presence of a zeolite-based catalyst. The synthesised zeolite-based catalyst is characterised by high porosity (the specific surface area of 350 m2 /g) and acidity (0.34 mmol/g). The use of the zeolite-based catalyst increases the yield of the gaseous and liquid products of pyrolysis by ca. 5 % in comparison with the non-catalytic one. Despite this increase seems to be negligible, the composition of the products was changed sufficiently because of the higher degree of feedstock decomposition. The addition of pure zeolite into the pyrolysis zone led to an increase in furanes and phenols yield for 3 times while the addition of Fe-ZSM-5 catalyst increased twice the yield of acids/esters, and hydrocarbons. [ABSTRACT FROM AUTHOR]

Flax shive is a highly lignified nonfibrous plant parts obtained from the scutching of straw flax to produce fibers. It is one of the multi-tonnage agricultural wastes. The use of the flax shive as a source for the valuable products is a promising way to solve the problem of the waste processing. This work is devoted to the study of composition and properties of the products of slow and fast pyrolysis of the flax shive. It was found that the slow pyrolysis results in a higher degree of the feedstock decomposition as well as in a higher yield of valuable gases and liquids. The gaseous product yield was found to be over 35 wt. % for the slow pyrolysis, and about 25 wt. % for the fast pyrolysis. For the gaseous products, methane concentration was found to be twice lower for the fast pyrolysis in comparison with the slow one. This decreases the calorific value of gases and leads to the low feasibility of the process. Interestingly, the fast pyrolysis resulted only 20 wt. % of liquids, while for the slow one, a twice increase (ca. 40 wt. %) of liquid yield was obtained. The liquid obtained in a fast mode contained the higher number of carboxylic acids and furanes, while the product obtained in a slow pyrolysis was characterised by the higher concentration of phenols, aldehydes and hydrocarbons increasing its further application. The solid residue obtained by the slow pyrolysis was found to have a higher porosity in comparison with the sample obtained by the fast mode. As the solid residue can be used as an adsorbent, the porosity is a critical parameter to choice the proper mode for flax shive thermal processing. [ABSTRACT FROM AUTHOR]

It is known that the increasing demand for cement production is linked to the increasing world population, and the rapid development of construction technology. As a result of these factors, cement plants are causing a massive environmental problem by emitting CO2 into the atmosphere. This significant air pollution may contribute to global warming. The search for alternative eco-friendly materials is an urgent need. Fly ash is a by-product in the form of powder produced by burning pulverised coal in power plants in huge quantities. Having no useful application, it is an organic waste, causing problems in landfilling. It is a pozzolanic material high in alumina and silica, which in the presence of water, acquires the cementitious properties of a renewable secondary cement-based material. When it is added to different types of binder, a new type of binder can be formed due to the mutual influence of fly ash on the nature and speed of the processes. The aim of the study was to develop a composition based on fly ash with a high content of free calcium oxide to replace cement with an alternative binder in the production of structural materials. For this, it was made a series of composite samples of different properties to obtain multilevel reinforcement. These samples showed high compressive strength (up to 90 MPa), indicating the synergistic effect of the composite components and their proper selection in building structures. [ABSTRACT FROM AUTHOR]

The article presents a model of non-hydration hardening of dispersed systems - mineral binders (without the stage of hydration) and the results of studies of gypsum stone with ash filler from the standpoint of the formation of the optimal structure of the material of non-hydration hardening, as well as its density and strength. The model assumes the use of binary mixtures of dispersed components with different dispersions. The study was based on data on the granulometric composition and dispersion of gypsum powders and aluminosilicate microspheres. It was isolated from the ash-slag mixture - waste from a thermal power plant. The aluminosilicate microsphere contains not only microsized spherical particles of the amorphous phase but also nanosized grains in a sufficient amount. This makes it possible to control the particle packing density. Experimental verification of the optimization of the granulometric composition of a binary dispersed system based on gypsum and ash microspheres was carried out. Based on the results, the optimal content of the filler in the composition of the non-hydration hardening structure was established. It is shown that filling with highly dispersed particles affects the performance properties of the resulting modified stone. [ABSTRACT FROM AUTHOR]

The work is devoted to the chemical modification of the natural chitosan polymer to improve its quality and suitability for further use in chemical processes. Chitosan samples with an increased degree of deacetylation and a reduced molecular weight were synthesized by the purification with sodium hydroxide with subsequent re-precipitation. Additionally, the chitosan succinate, chitosan hydrochloride, and thyoled chitosan were obtained. These compounds are characterized by solubility in a wider pH range compared to the commercially available samples. For each of the synthesized samples, infrared diffusion reflection spectra were obtained. The modified samples of chitosan were used for obtaining nanoparticles and finely-dispersed films. [ABSTRACT FROM AUTHOR]

Carbon materials are widely used in catalysis as effective catalyst supports. Carbon supports can be produced from coal, organic precursors, biomass, and polymer wastes. Biomass is one of the promising sources used to produce carbon-based materials with a high surface area and a hierarchical structure. In this review, we briefly discuss the methods of biomass-derived carbon supported catalyst preparation and their application in biodiesel production, organic synthesis reactions, and electrocatalysis. [ABSTRACT FROM AUTHOR]

This paper reports palladium (Pd)-containing nanoparticle (NP) formation in nanoporous hypercrosslinked polystyrene (HPS), using Pd acetate as a precursor. It was demonstrated that the NP size and composition can be controlled by Pd acetate loading and post-impregnation treatment with hydrogen gas. The catalyst structure was studied using transmission electron microscopy (TEM), X-ray fluorescence analysis, X-ray photoelectron spectroscopy (XPS) and nitrogen physisorption measurements. The catalytic properties of the catalysts developed have been studied in a green process of D-glucose oxidation to D-gluconic acid. The latter and its Ca salt are used for pharmaceuticals and food supplement production. The most active catalyst was found to contain 1.7 nm Pd/PdO NPs at 1.09 wt% Pd loading. It provided 99.6% selectivity at 93.6% conversion. Repeated use of the same catalyst demonstrated exceptional stability in D-glucose oxidation, making these catalysts promising for industrial applications in sustainable processes.

CO2 hydrogenation to methanol is an important process that could solve the problem of emitted CO2 that contributes to environmental concern. Here we developed Cr-, Cr-Zn-, and Cr-Ni-containing nanocomposites based on a solid support (SiO2 or Al2O3) with embedded magnetic nanoparticles (NPs) and covered by a cross-linked pyridylphenylene polymer layer. The decomposition of Cr, Zn, and Ni precursors in the presence of supports containing magnetic oxide led to formation of amorphous metal oxides evenly distributed over the support-polymer space, together with the partial diffusion of metal species into magnetic NPs. We demonstrated the catalytic activity of Cr2O3 in the hydrogenation reaction of CO2 to methanol, which was further increased by 50% and 204% by incorporation of Ni and Zn species, respectively. The fine intermixing of metal species ensures an enhanced methanol productivity. Careful adjustment of constituent elements, e.g., catalytic metal, type of support, presence of magnetic NPs, and deposition of hydrophobic polymer layer contributes to the synergetic promotional effect required for activation of CO2 molecules as well. The results of catalytic recycle experiments revealed excellent stability of the catalysts due to protective role of hydrophobic polymer. [ABSTRACT FROM AUTHOR]

The integration of biofuel upgrading processes in the existing technologies of crude oil refining is considered to be one of the promising directions for the production of liquid motor fuels. In this work, the co-processing of bio-oil obtained from biomass waste and heavy oil fractions in the supercritical solvent was studied. The bio-oil was obtained by the slow pyrolysis of birch and pine wood sawdust in the presence of a Fe-containing zeolitebased catalyst. The influence of the catalyst on the yield and composition of liquid products was studied. To find the optimal reaction conditions, the co-processing of the model compounds (anisole - eicosane - dibenzothiophene) was carried out by varying the solvent, reaction temperature, and the initial nitrogen pressure. Full removal of oxygen and sulfur as well as a decrease in the concentration of heavy and polyaromatic compounds from the feedstock were observed under the following process parameters: solvent - propanol-2, reaction temperature - 260 °C, initial nitrogen pressure - 1.5 MPa, total pressure - 7.2 MPa. [ABSTRACT FROM AUTHOR]

This paper presents the results of comparative studies of the effect of highly dispersed fillers on the mechanical and structural characteristics of pressed composites based on gypsum. As microfillers, powders of metakaolin and the ash were introduced into the composition of the gypsum mixture. The active component in the form of metakaolin affects the structure and properties of pressed stone. The average median grain size of metakaolin predetermines an increase in packing density due to the filling of voids between larger particles of gypsum with a highly dispersed phase. The effect of increasing the density of the modified composite has been established. Studies of water absorption of stone with the addition of metakaolin have established an increase in water resistance and a decrease in water absorption of a modified composite. The results of studies of gypsum with ash additive confirm the effectiveness of the introduction of the ash in terms of strength and density. As in the case of metakaolin. Gypsum with the addition of ash has not only increased density and, as a result, high performance, but also high creep resistance. Based on the results of the microstructural and spectral analysis of pure and modified stone, a comparison was made of the elemental composition of the original stone and the modified composite on the grain surface and in the contact zones of gypsum particles with particles of fillers. They confirm the participation of additives in the formation of crystallites of the composite and the mechanical compaction of its structure. [ABSTRACT FROM AUTHOR]

In the work, the influence of the initial characteristics of feedstock on the yield, composition, and properties of fast pyrolysis products was studied. Samples of the original flax shive and its cellulose residue obtained as a result of alkaline hydrolysis were chosen as the raw materials for the investigation of fast pyrolysis to obtain useful products - phenyl propane derivatives (guaiacyl- and syringyl propanols, propenes, and propanes). The use of preliminary chemical processing of plant raw materials is aimed at maximizing the use of the initial potential of raw materials, as well as reducing energy costs and improving the quality of pyrolysis products. The paper discusses the dependence of the composition and properties of fast pyrolysis products on the process conditions - temperature, retention time of the raw material in the heating zone, and the diameter of the particle of the feedstock. The optimal conditions for fast pyrolysis for flax processing waste are temperature 700 °C, particle size 0.25 -1 mm, and particle residence time in the heating zone of 4.4 s. The results of a study of the process of fast pyrolysis of flax processing waste in the presence of a ZSM-5 catalyst are also presented. The presence of ZSM-5 zeolite increases the content of ethylene, hydrogen, and carbon dioxide, which is probably associated with the cracking of volatile products passing through the catalyst heated to high temperatures. The composition of liquid products of fast pyrolysis obtained using a thermocatalytic purification stage on the synthetic zeolite ZSM-5 was significantly reduced in the number of chemicals compared to the compositions of liquid products of fast pyrolysis obtained without a purification stage. [ABSTRACT FROM AUTHOR]

The energy sector of the Russian Federation based on coal to generate heat and electricity is a major source of ash and slag. The dumps of this waste occupy large areas and at the same time cause environmental problems. Ash and slag contain alumina and other valuable products such as silica, magnetite etc. The ashes of large thermal coal-fired power plants of the Ural region - Troitskaya, Reftinskaya, Verkhnetagilskaya and others - contain about 28-32 % wt alumina. The waste obtained could become the technogenic raw materials for the production of aluminum. This will allow partially replacing the import of alumina to Russia from foreign countries. The current work presents the results of experimental studies aimed at developing a technology for extracting high-quality alumina from the high-alumina ash of coal-fired power plants. In the study, the sintering method was used to obtain Al2O3 from ash for the first time. Because of high silica concentration in ash, the direct sintering cannot be applied. To remove SiO2, the ash samples collected from three thermal power plants of Ural region were preliminary treated with alkali solution and then thermally treated. The influence of various technological parameters on the process of obtaining the target product has been studied. To obtain an enriched alumina concentrate, the ash was found to be treated with 20 % wt of NaOH solution at 90-100 °C. The further thermal treatment should be performed at a temperature of 1,000-1,200 °C to activate ash. The sintering of the activated ash results in the production of Al2O3 with a purity of 97-98 % wt. [ABSTRACT FROM AUTHOR]