Adsorption characteristics of polyacrylamide and sulfonate-containing polyacrylamide copolymers on sodium kaolinite

Polyacrylamide and its copolymer containing 6.8 mole % 2-acrylamido-2-methylpropane sulfonic acid were prepared by an irradiation-initiated precipitation polymerization technique. The polymer was characterized by intrinsic viscosity under conditions similar to those used during adsorption measurements. Hydrolytic degradation of the polyacrylamide was found to be negligible under conditions used. The adsorption substrate, sodium kaolinite, was prepared by extensive ion exchange treatment. Equilibrium adsorption of the polymers on the sodium kaolinite was made as a function of polymer concentration, solution pH, ionic strength, and temperature.     

Sintering kinetics of zirconium dioxide

Conclusions We investigated the sintering of zirconium dioxide over the temperature range 2000–2350°K as a function of the purity of the material and the defectivity of the oxide crystal lattice. The activation energy of sintering and the vacancy diffusion constant were calculated.The decrease in activation energy resulting from distortion of the crystal lattice is, on the whole, inadequate for activation of sintering.Translated from Ogneupory, No.5, pp. 51–57, May, 1969.     

二氧化氯对聚丙烯酰胺降解作用的实验研究

随着三次采油技术的不断发展,油井堵塞问题越来越严重。主要研究了不同浓度的二氧化氯对聚丙烯酰胺的降解作用,以及温度对其影响,并对二氧化氯降解聚丙烯酰胺的机理进行了探讨。主要测定在6 h内,随着时间的变化,不同温度及不同二氧化氯浓度下聚丙烯酰胺的黏度,以此来判定二氧化氯对聚丙烯酰胺的降解效果。结果表明：在室温下,降解2%（质量分数）的聚丙烯酰胺溶液的最佳二氧化氯质量分数为4×10^-3;当二氧化氯质量分数为4×10^-3时,降解2%（质量分数）的聚丙烯酰胺溶液的最佳温度为60 ℃。     

Dynamic synthesis of zirconium dioxide powders

We investigated the process of zirconium dioxide powder synthesis by shock wave loading of a porous metal and the subsequent dispersion. The synthesized powder consists of hollow spherical shells and highly porous conglomerates with a 500 μm mean dimension. The specific surface of the powder is independent of the particle size and is 1.25±0.35 m²/g. The tetragonal modification predominates for large dimensions, while the monoclinic is more common in the small. The possibility of stabilizing the oxides in the high-temperature phase is investigated. Deceased. Krasnoyarsk Scientific Center, Siberian Branch, Russian Academy of Sciences, 660036 Krasnoyarsk. Translated from Fizika Goreniya i Vzryva, Vol. 29, No. 6, pp. 78–81, November–December, 1993.     

Electrical conductivity of hot-pressed zirconium dioxide

Conclusions Hot-pressing was used to obtain samples of products of zirconium dioxide with a density of 97–99% of the theoretical value. Their electrical conductivity was considerably greater than in the case of sintered samples with the corresponding stabilizing additive. In the temperature interval 1300–2000°C, it was lower than 1 ^–1.cm^–1 in all cases.Translated from Ogneupory, No. 3, pp. 44–46, March, 1969.     

The effect of oxides on stabilization of zirconium dioxide

The processes of coprecipitation of calcium, strontium, and cadmium salts are studied. It is shown that alkaline coprecipitation produces zirconates, which in heat treatment form stable solid solutions.     

Adsorption of sulphur dioxide on coal

A study was made of the feasibility of using coal as an adsorbent material for the removal of sulphur dioxide from stack gases emitted to the atmosphere by different industries. From preliminary results, it would appear that coal is to be favoured by a raw materials/cost-effectiveness ratio of 2:1. The work shows semi-quantitatively that the adsorptive capacity of sulphur dioxide on coal varies slightly from one coal to another and that when coal is used and re-used through numerous (?40) cycles, its effectiveness as an adsorbent for sulphur dioxide is not greatly reduced. Moreover, this research supports the view that the heating value, ash, sulphur content, etc. of most types of coal changes only slightly after repeated usage as an adsorbent for sulphur dioxide. If, as these findings indicate, coal can initially be used as a sulphur dioxide adsorbent prior to its use as a fuel, economic potential for commercial applications should be enhanced. Empirical equations, developed to correlate the adsorption-desorption characteristics of different coals, can be used as a basis for prediction and comparison by future investigators to further explore this research.     

Vacuum sintering of a ceramic based on zirconium dioxide

The results of a study of the phase composition and mechanical properties of a ceramic based on ZrO₂-Y2O₃ after vacuum sintering of powders with complex morphology in a wide range of temperatures and sintering holding times are reported. Dense ceramic materials with high mechanical properties were obtained.Translated from Steklo i Keramika, Nos. 5–6, pp. 27–29, May–June, 1994.     

Electric discharge sintering of ceramics based on zirconium dioxide

The possibility of sintering zirconium ceramics in the plasma of a glow discharge is investigated. It is shown that sintering in ammonia plasma substantially improves the physicomechanical characteristics of sintered materials as compared to sintering in air plasma and in vacuum heat-treating furnaces. The improvement of the properties is mainly due to the additional stabilization of high-temperature ZrO₂ phases by nitrogen and is also explained by specific sintering conditions in the electric field of the glow discharge.Translated from Ogneupory, No. 9, pp. 20 – 22, September, 1994.     

Adsorption of new hydrophobic polyacrylamide on the calcite surface

A hydrophobic polyacrylamide (HPAM) was synthesized by aqueous free‐radical chain polymerization to understand the adsorption action of the polymer on the calcite during operating stimulation. The polymer was designed as acrylamide (AM)/2‐acrylamide‐2‐methylpropanesulfonic acid (AMPS)/2‐methacryloyloxyethyl 12‐alkyl dimethyl ammonium bromide (MADA). The structure of the polymer was characterized by Fourier transform infrared spectroscopy. The adsorption properties of the polyacrylamide onto pure calcite was investigated. When we compared the ζ potentials of the calcite particles in the presence and absence of HPAM, the adsorbed amount was affected by different factors, and the adsorption behaviors were examined to determine the adsorption layer. The results of the ζ potential measurements indicated that the particles were negatively charged between pHs of 6 and 12, and the presence of HPAM did not reverse that. Equilibrium adsorption studies showed that the adsorbed amount was affected by the concentration of HPAM, liquid‐to‐solid ratio, calcite particle size, concentration of background ions, and temperature, which were related the adsorption behaviors of HPAM. Hydrogen bonds between HPAM and calcite were important because the adsorbed amount was significantly reduced when the hydrogen bonds were broken by urea. It is necessary to develop a more active reagent that can break the hydrogen bonds and improve the effect of hydraulic fracturing. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45314.     

聚丙烯酰胺在黑土上的吸附解吸特性研究

采用静态吸附法研究了聚丙烯酰胺在黑土上的吸附行为,考查了不同吸附时间对土壤吸附量的影响,得出了聚丙烯酰胺在土壤上的吸附等温线。并且研究了聚丙烯酰胺在黑土上的解吸行为,探讨了振荡时间、液固质量比、温度、pH值对黑土中聚丙烯酰胺解吸的影响。结果表明,聚丙烯酰胺在黑土上的吸附等温线符合Langmu ir吸附模式,饱和吸附质量比为1.17 mg/g,聚丙烯酰胺在土壤上有很强的吸附亲合力,在实验条件下,最大解吸量仅为总量的25%。     

Stabilization of high-temperature modification of zirconium dioxide

Translated from Steklo i Keramika, No. 9, pp. 22–23, September, 1991.     

纳米级二氧化锆的制备和应用

纳米二氧化锆是一种新型的高科技材料,有着广泛而重要的用途。根据国内外研究制备的最新进展及其发展趋势,综述了纳米级二氧化锆的制备技术和近年来新的应用领域和研究前沿。