卷 91, 编号 8 (2018)

Physicochemical characteristics and hydrocarbon composition of highly aromatic wastes (light gas oil from catalytic cracking, pyrolysis tar, coal tar, coal gasification tar) as a feedstock for producing high-density jet fuels are considered. The hydrogenation reactions of polycyclic aromatic hydrocarbons, including mixtures of hydrocarbons with different numbers of rings, are described. Catalysts for hydrogenation of highly aromatic waste to obtain fuel fractions are considered. Particular attention is paid to catalyst deactivation in the course of processing of this feedstock. A separate section deals with the choice and implementation of procedures for processing highly aromatic feedstock to obtain jet and diesel fuels.

Process for deep plasma-chemical etching of single-crystal quartz plates in a SF₆/O₂ gas mixture was developed. The method of scientific experiment design based on the Taguchi matrix technique was used to rank basic technological parameters (bias voltage applied to the substrate holder, output power of the high-frequency generator, oxygen flow rate, and position of the substrate holder relative to the lower edge of the discharge chamber) as regards their influence on the etching rate. The ranking results were used to optimize the plasma-chemical etching process and perform a control experiment on through etching of windows with large linear dimensions (3 × 10 mm) in a single-crystal quartz plate (z-cut) with thickness of 369 μm.

Co_1–xZn_xFe₂O₄ was prepared by citrate precursor method using raw materials: citric acid, cobalt, zinc and iron nitrates and by following calcination at 600°C. This assessment presents the effect of substitution of the Zn2+ ion on the structural properties of cobalt nanoferrite. The structural characteristics of the calcined samples were determined by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS). X-ray diffraction studies of the nanoparticles heat-treated at 600°C confirms that the crystallite size is in the range of 22 to 29 mm and also the X-ray diffraction analysis indicates the formation of single phase ferrite particles in nano size. The morphology of the calcined sample was investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The mean particle size of Co_0.6Zn_0.4Fe₂O₄ was determined to be 19 nm calculated from TEM which is supporting the X-ray diffraction studies. The Fourier transform infrared spectra (FTIR) show two strong absorption bands in the series of ferrites between the range of 4500–500 cm⁻¹ responsible for the characteristic of spinel ferrites. The high-frequency band and low-frequency band are assigned to the tetrahedral and octahedral complexes, respectively. The weight %, atomic %, and elemental analysis of calcined samples were confirmed by elemental spectral signals of energy dispersive spectroscopy (EDS). At the room temperature, magnetic measurements of pure ZnFe₂O₄ and Co_0.6Zn_0.4Fe₂O₄ were calculated based on hysteresis curves (Hc), it is observed that the substitution of nonmagnetic Zn²⁺ ion increases the magnetic behavior in mixed cobalt-zinc ferrites. The antimicrobial activity of ZnFe₂O₄, Co_0.6Zn_0.4Fe₂O₄ synthesized nanoferrites has been successfully tested against harmful microbes.

Fundamental aspects of how films of the SrZr_0.95Y_0.05O_3–δ electrolyte are formed from alcoholic-aqueous solutions of salts at various solution characteristics (salt concentration, viscosity, and relative content of water) were studied. It was found that, to obtain dense film electrolytes, it is necessary to use low-viscosity solutions with the minimum content of water. The revealed fundamental aspects will make it possible to obtain dense film membranes based on strontium zirconate for solid-oxide fuel cells by the technologically simple solution method. Solutions with high content of water can be used to form an external porous layer on the surface of a dense membrane, which must favor an increase in the power of fuel cells.

Obtaining and using polymeric composite materials with biocide properties is of considerable practical interest both for making construction materials stable against biological corrosion and for improving the sanitary-epidemiological situation. The method suggested for obtaining biocide polymeric composites is based on using new guanine-containing polymers immobilized on montmorillonite as biocide additives. Macromolecular compounds based on guanidine polymers are characterized by high biocide efficiency and low toxicity, and their use as organomineral complexes with montmorillonite can rule out washing-out of the additive from the composite and improve the distribution of the additive in the composite. Methods are suggested for obtaining organomineral complexes in a wide range of compositions. It is shown that composites based on polyethylene and the additives have high biocide efficiency toward micromycetes and gram-positive and gram-negative bacteria.

Molecular theory of wetting was used to calculate the specific free surface energy of membranes based on amorphous polymers of varied chemical structure from experimental wetting angles obtained for test fluids. A relationship was found between the dispersion component of the surface energy of a membrane, its gas permeability, and free volume of the polymer. This makes it possible to employ the wetting method to prognosticate the transport properties of polymeric membranes. In wetting of membranes with aqueous solutions of alcohols, the concentration of an alcohol corresponding to the onset of its sorption into the membrane was determined. The correlation of the value obtained with the alcohol concentration that corresponds to the onset of sorption and is determined independently by the gravimetric method enables use of wetting angles for optimizing the conditions of experiments on nanofiltration and pervaporation.

Physicomechanical and surface properties of films of copolymers of methacrylic acid with methyl acrylate, which have close compositions and molecular masses (M_n ≈ 5.7 × 10⁴) and various chain structures (gradient copolymer and statistical copolymer), were studied. The thermodynamic characteristics of the copolymers were determined; two glass-transition points (29.6 and 141.0°C) were found for the gradient copolymer, and one glass-transition point of 40.1°C, for the copolymer with a statistical distribution of units along the chain. It was found that more mechanically strong films with tensile stress of 2.8 MPa are characteristic of the gradient copolymer. The wetting method was used to determine by using the Hood–Kaelble–Dann–Fowkes approach the surface Gibbs energies of the films and their polar and dispersion components. Atomic-force microscopy was used to find heterogeneities (0.1–0.3 μm) on the surface of a film of a statistical copolymer, whereas the film of a gradient polymer has a homogeneous structure.

new material of Cu(OH)₂ nanostructures was prepared using cupric nitrate and sodium hydroxide as raw materials by the chemical precipitation method. The Cu(OH)₂ nanostructures were characterized by scanning electron microscope, transmission electron microscopy, infrared spectrometer, and X-ray diffractometer. The results showed that the Cu(OH)₂ nanostructures exhibited excellent uniform and dispersion at 40°C. A series of factors was investigated to effect the photocatalytic efficiency of methyl orange (MO), such as the concentration of Cu(OH)₂ nanostructures, the reaction time of the Cu(OH)₂ nanostructures, the initial concentration of MO, and so on. As a result, the Cu(OH)₂ nanostructures exhibited excellent photocatalytic efficiency with the concentration of 20 mg L^–1 Cu(OH)₂ nanostructures, the initial concentration of MO was 15 mg L^–1 and the stirring time was 70 min.

A series of NiMoW/P-Al₂O₃ catalysts with different Mo/W ratios (sample containing Mo only, Mo/W = 2: 1, Mo/W = 1: 1, Mo/W = 1: 2, and sample containing W only; P₂O₅ content of the support 2.0 wt %) were synthesized. The precursors of the active phase were the heteropoly acids H₃PMo₁₂O₄₀∙nH₂O and H₃PW₁₂O₄₀∙nH₂O, and also nickel citrate. The sulfide phase in the samples was studied by high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy; the catalytic activity of the samples in dibenzothiophene hydrodesulfurization and naphthalene hydrogenation was determined. For the dibenzothiophene hydrogenolysis in the presence of quinoline and naphthalene (content in the model mixture, wt %: dibenzothiophene 0.3, naphthalene 1.5, and quinoline 0.5), k_HDS for different samples is in the range 17.6–42.5 h^–1 at 275°C and 24.6–45.9 h^–1 at 300°C. For the naphthalene hydrogenation, k_HYD varies from 0.79 to 1.89 h^–1 at 275°C and from 0.91 to 3.78 h^–1 at 300°C. The sample based on molybdenum showed the highest activity in hydrogenation and hydrodesulfurization.

A poly[1-(trimethylsilyl)-1-propyne] membrane was studied in a thermopervaporation process for ethanol recovery from fermentation media. Four commercial composite membranes based on polysiloxanes (Pervap 4060, Pervatech PDMS, PolyAn, and MDK-3) were studied for comparison. The dependences of the permeate flux, permeate concentration, separation factor, and pervaporation separation index on the temperature of the feed mixture (5 wt % ethanol in water) were obtained. The maximal values of the ethanol concentration in the permeate (35 wt %) and separation factor (10.2) were obtained for the poly[1-(trimethylsilyl)-1-propyne] membrane, whereas the PolyAn membrane provided the highest permeate flux (5.4 kg m^–2 h^–1). The ethanol/ water separation factor for the systems studied has a maximum at 60°С; this temperature of the feed mixture is optimum for recovering ethanol from aqueous media by thermopervaporation. The existing membranes based on polysiloxanes show low ethanol–water selectivity (less than 1). Poly[1-(trimethylsilyl)-1-propyne] membranes are the most promising for recovering bioethanol from fermentation mixtures by thermopervaporation, because they showed the highest selectivity to ethanol.