Vol 90, No 2 (2017)

Synthesis of ethylene on trefoil and cylindrical experimental acid-modified aluminum oxide samples was studied under an ethanol (94%) gas load of 920–2200 h^–1 and heat-carrier temperature of 400–440°C. In the conditions of a 98% ethanol conversion, the higher activity of the trefoil made it possible to reduce the height of the bed and its hydraulic resistance and, accordingly, raise the specific catalyst throughput for ethylene. Compared with industrial aluminum oxide, the throughput of 1 g of the catalyst for ethylene on experimental samples is higher by 2.5–6.5 kg yr^–1, and the specific expenditure of ethanol is lower by 0.22–0.23 kg kg^–1. The endothermic process in a tubular reactor is characterized by a high parametric sensitivity of the average integral temperature along the catalyst bed, with the average temperature being higher on the less active catalyst. Thus, the higher average temperature can compensate for the lower activity of the catalyst without additional increase in the contact duration and(or) heat-carrier temperature.

Study of the photocatalytic activity of nanomaterials based on potassium polytitanate modified with transition metal ions (Ni²⁺, Cr³⁺, Cu²⁺) demonstrated that the cation composition, morphology of photocatalyst particles, and their size strongly affect the photocatalytic activity. The rate of the photoinduced hydrogen evolution from the aqueous-alcoholic solution grows in the series of potassium polytitanates modified with Cu²⁺, Ni²⁺, Cr³⁺ ions, and that from pure water, for potassium polytitanates modified with Ni²⁺,Cr³⁺, Cu²⁺ ions. The capacity for intercalation of water into the interlayer space does not strongly affect the rate of the photoinduced hydrogen evolution. It was shown that potassium polytitanate modified with Cr³⁺ ions has the maximum quantum efficiency (30%).

Modification of porous glass with copper(II) oxide with planar structure does not change the run of the water-adsorption isotherm, whereas in the case when nanoparticles are formed from the supported oxide, a cluster-type adsorption mechanism is operative when a relative pressure p/p₀ > 0.5 is reached. These specific features are reflected in the different dependences of the electrical resistance of the samples on humidity. It was shown that a porous glass with distributed copper(II)oxide planar layer can be used as a sensitive element of a resistive humidity sensor.

Inverse gas chromatography was used to study the stability of rifabutin and cyclodextrin complexes in water. The thermodynamic mixing functions were determined in the system rifabutin‒cyclodextrin‒water. Addition of hydroxypropyl-β-cyclodextrin to rifabutin creates in water a thermodynamically stable complex, with the solubility of rifabutin in water thereby raised and this antibiotic made more bioavailable in curing of tuberculosis.

Turbidimetric titration and laser scattering methods were used to assess the phase behavior of mixtures of chitosan and hyaluronic acid in aqueous solutions in relation to interaction conditions. Conditions were found in which stable water dispersions with particle size of up to 573 nm can be obtained. It was found that the molar ratios and the overall concentration mode of the starting-polyelectrolyte solutions affect the particle size.

The choice of parameters of the polycondensation procedure for combining the components in forming polymer matrix composites based on fibrous and dispersed fillers and phenol–formaldehyde resin is substantiated. The materials formed using the polycondensation procedure for compounding the components considerably surpass in the physicochemical and mechanical properties the composites prepared using the traditional technology.

The effect of hollow aluminosilicate microspheres on the Payne effect and on physicomechanical, thermal, fire-retardant, and heat-protecting properties of elastomer compounds based on ethylene–propylene–diene rubber was studied. Based on the results obtained, the mechanism of the interaction of the elastomer matrix with the microspheres was suggested. Enhancement of the filler–matrix and filler–filler interaction favors additional three-dimensional cross-linking, which influences the set of the physicomechanical and thermal properties, and manifestation of the reinforcing effect in a coke layer under the conditions of erosion removal and detachment of the material with a high-velocity gas flow.

Treatment of the filler surface with a silane dressing agent, ensuring the chemical interaction on the filler–binder interface, and ultrasonic treatment of the compound enhance the physicomechanical properties of the epoxy composite: The failure stress and bending elastic modulus increase by a factor of 2–3. Considerable (2.5- fold) increase in the impact resilience even at 50% filling should be particularly noted. Introduction of modified brick dust enhances the heat resistance and thermal conductivity of the epoxy composite.

In this study, adsorption capacity of textile red dye on alkylated kaolin was investigated through batch mode. Accordingly, raw kaolin was alkylated via NaOH treatment. The work was carried out in two steps. At first step, the effect of various alkylation conditions of kaolin on its dye adsorption performance was studied using the model equation designed by 2-level factorial design. Three factors were changed in two level including NaOH solution temperature (45–75°C), mixing time (3–24 h), and NaOH solution concentration (0.1–2 M). The resultant model showed 91% of the variability in data used to fit dye adsorption capacity values. However, the analysis of variance revealed that the fitted model is high significant. Based on the predicting model, the optimal alkylation conditions with desirability factor of 0.911 were obtained at temperature of 75°C, NaOH concentration of 0.1 M and after 24 h mixing. At step two, chemical content, bonds and functional groups of the treated kaolin, which was prepared based on the optimum condition and compared with the raw kaolin via X-ray fluorescence (XRF) analysis and Fourier transform infrared analysis (FTIR). The results show slight reduction in SiO₂ content. Finally, the adsorption capacity of dye on both treated and raw kaolin was investigated.

M-type strontium hexaferrite substituted by Zr⁴⁺, Zn²⁺, and Co²⁺ was firstly synthesized by a sol-gel auto combustion method. Then the polyaniline/hexaferrite nanocomposite with 20 wt % hexaferrite was prepared by in situ polymerization method. The structure, morphology, and composition of substituted hexaferrite, polyaniline and their composition were investigated by using XRD, FTIR, TGA-DSC, UV-Vis spectroscopy, and FESEM techniques. The results showed that M-type hexaferrite nanoparticles were formed and nanoparticles were effectively coated by polyaniline chains. The magnetic properties of samples were measured by the vibrating sample magnetometer (VSM). The saturation magnetization (M_s), magnetic remanence (M_r), and coercivity (Hc) of composite are lower than those of pure hexaferrite. The microwave absorption properties of samples were measured by vector network analyzer (VNA). The results indicated that the minimum reflection loss (RL) of composite is–20 dB at 10.1 GHz and its bandwidth with more than 90% absorption is up to 3.5 GHz which has covered the overall X-band.

Polyacrylamide (PAM)-silica microspheres with core-shell structure are synthesized by inverse microemulsion polymerization in this study for the application of water shut-off due to high strength of nanosilica, crosslinked shell of PAM and strong interaction between PAM and silica. The core-shell microspheres flow into the high permeable layers along with injected water, meanwhile, swell after absorbing water and migrate into the deeper layer under the pressure by deformation, which efficiently increase the pressure of low and medium permeable layers, and decrease the loss of water into high permeable layers. Most resources of crude oil locate in low and medium permeable layers, and this work plays a very important role in the enhancement of recovery ratio of crude oil by new material. Transmission electron microscope (TEM), digital microscopes, dynamic light scattering (DLS), and thermogravimetric analysis (TGA) are used to study the shape, size and high temperature resistant of the microsphere. Moreover, capillary flow experiments, nuclear-pore film filtration, and sand packed tube displacement experiment are applied to analysis the mechanisms of deep profile control.