Sorption of Hexacyanoferrate(II,III) Anions on Nickel(II) Hydroxide

Fe(CN)₆ ^{3 -} and Fe(CN)₆ ^{4 -} anions are sorbed from aqueous solutions of their potassium and cesium salts on -Ni(OH)2 by the mechanism of anion exchange with hydroxy groups. Alkali metal cations (K⁺, Cs⁺) are also partly sorbed on nickel(II) hydroxide in the form of anionic complexes (K,Cs) _z Fe(CN)₆ ^{(n - z)-}, where n = 3 or 4 (0 < z < n). The chemical composition of the new phase appearing in contact of nickel(II) hydroxide with aqueous potassium and cesium hexacyanoferrates(II, III) was determined by X-ray phase analysis and IR spectroscopy.     

Calculation of boltzmann equation collision integral and accurate solution of relaxation problem

A method of solving the Boltzmann equation on the basis of expansion in Maxwell distributions (Maxwellians) is developed. The calculation of the collision integral consists of two stages: calculation of a two-Maxwellian collision integral and its subsequent expansion in Maxwellians. A special numerical procedure is proposed for approximating functions of one and two variables by a finite number of exponentials; the mean-square deviation of the accurate and approximate functions is minimized and certain moments of these functions are brought into agreement. For a solid-sphere model, the two-Maxwellian collision integral comprises a set of 24 functions over the whole range of the parameters investigated. The Euler method is used to examine the equalization of velocities and temperatures in the gas (quasishock) and resonance recharging of ions on atoms. The accuracy of the solutions obtained is estimated.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 5, pp. 132–141, September–October, 1977.     

Dynamics of three-component exchange on a cationite with lithium manganese spinel structure

The dynamics of the sorption of lithium ions on a cationite with lithium manganese spinel structure from neutral solutions against the background of a large amount of sodium ions was studied. It was demonstrated that the dynamics of the ion exchange of these ions from their mixed solutions differs significantly from that observed for their individual solutions. The experimental results can be explained by assuming that, at a large concentration of sodium ions in the solution, they saturate the surface of the cationite and that lithium ions are predominantly exchanged for sodium ions. This assumption is supported by the results of a mathematical modeling.     

Mercury(II) Sorption on Nickel(II) Hydroxide: Influence of Halide Ion Concentration and pH of the Solutions

Sorption of Hg(II) on -Ni(OH)₂ was studied as influenced by chloride ion concentration and pH of the solutions, affecting the Hg(II) speciation. The sorption mechanism was considered.     

Production of Complex Nitrogen-Potassium and Nitrogen-Magnesium Fertilizers from Substandard Urea Fractions

The production of NK and NMg fertilizers of various compositions from urea and finely crystalline potassium sulfate or urea and caustic magnesite powder was optimized. The commercial characteristics (qualitative composition, hygroscopicity, and strength) of the granulated NK and NMg fertilizers obtained were studied. The possibility of undesirable chemical reactions occurring on fusing potassium sulfate or magnesium oxide with urea in the fertilizer mixture was studied by X-ray phase analysis and IR spectroscopy.     

Variation of the composition and properties of lithium manganese oxide spinel in lithiation-delithiation cycles

The behavior of the variable-composition spinel Li_{1 + x} Mn_{2 ? x} O₄ is examined in repeated cycles consisting of lithiation in 0.2 M LiOH and delithiation in 0.3 M HNO₃. For 0 < x < 0.33, delithiation is accompanied by the redox reaction 2Mn³⁺ → Mn⁴⁺ + Mn²⁺ and Li⁺ ? H⁺ ion exchange. The spinel undergoes partial conversion into λ-□MnO₂. Vacancies (□) build up at the 8a sites of the spinel structure. Mn²⁺ ions pass into the solution, and, accordingly, the spinel dissolves. Lithiation is accompanied by the redox reaction 4Mn⁴⁺ → 3Mn³⁺ + Mn⁷⁺ and ion exchange, and the proportion of vacancies □ at the 8a sites of the spinel structure decreases. The spinel undergoes partial dissolution because of Mn²⁺ and MnO _? ⁴ ions passing into the solution. The Li⁺ selectivity of the spinel is the property of the crystallite core. The crystallite surface is capable of sorbing Na⁺ ions.