Possibilities of micro X-ray fluorescence spectrometry of solutions with preconcentration

Results of investigations in energy-dispersive X-ray fluorescence analysis aimed at the development of a high-sensitivity method of microanalysis of solutions are presented. A combined scheme of analysis of one drop of solution of the volume several microliters is proposed and tested. The scheme includes a new preconcentration method based on the drop evaporation in the presence of a micrograin of a hydrophilic adsorbent followed by the microanalysis of the solid phase on the portable device with a polycapillary lens with a focal spot of 10 μm designed at the Institute of Physical Optics. Analytically meaningful X-ray fluorescence spectra are obtained using DETATA (grain diameter about 100 μm) and SAC8 (50 μm) adsorbents and individual drops of model solutions containing Mn, Fe, Co, Ni, Cu, and Zn (0.2 mg/L and higher) and analytical characteristics of the proposed approach are demonstrated.     

High-sensitivity X-ray fluorescence analysis of solutions with the use of a sorption accumulation microsystem

A mass-transfer kinetic model is proposed for an embedded sorption accumulation microsystem based on polycapillary structures to be used in the developed X-ray fluorescence analyzer with preconcentration. The model is used to substantiate a kinetic method for high-sensitivity X-ray fluorescence determination of elements in multicomponent solutions. With the use of this model, experimental data on X-ray fluorescence spectra are analyzed and kinetic and equilibrium parameters are found for the sorption of copper, nickel, manganese, iron, and zinc on the selective DETATA sorbent.     

Feasibility of Acid–Salt Processing of Alumina-Containing Raw Materials in a Closed-Loop Process

Russian Journal of Applied Chemistry - Acid methods for processing of bauxites and aluminosilicates with high silicon content become attractive in connection with the exhaustion of natural...     

A new nonisothermal ion-exchange method for enrichment of solutions

A new dual temperature ion-exchange method for concentration and separation of solutes, the “swinging wave” method, was described. The method can be used for the reactant-free enrichment of solutions in microcomponents. The effectiveness of the method applied to the enrichment of bromides in sea water on a highly basic anion-exchange resin was demonstrated, and technological characteristics of this process were studied using computer simulation and experimental studies. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya No. 12, pp. 2166–2172, December, 1997.     

Equilibrium of Br− and Cl− exchange on strong-basic anion-exchanger

The equilibrium of Br^– and Cl^– exchange is studied on the strong-basic anionexchangers. Quantitative characteristics which can be used for elaboration of dual-temperature separation processes have been obtained. An empirical equation for the dehydration extent of an anion in a phase of a sorbent has been suggested, allowing one to calculate the Br^– and Cl^– exchange equilibrium constants on the anion-exchanger in a wide temperature range.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2083–2089, December, 1994.     

Description of heterogeneity of the sorbent surface on the basis of adsorption kinetic data

The kinetics of adsorption of Rb⁺ and Cs⁺ ions on different non-polarized and polarized active carbons at temperatures of 25, 35, 45, and 65 °C was investigated. The obtained results were processed using the equations of the pseudo-first- and pseudo-second-order models. The pseudo-second-order model better describes the adsorption of alkaline metal ions on the carbons studied. The kinetic dependences of three types reflecting heterogeneity of the sorbent surface were revealed on the basis of the theoretical analysis of sorption systems.     

Kinetic Models of Batch Sorption in a Limited Volume

Russian Journal of Physical Chemistry A - The batch sorption kinetics described by a nonlinear equation with a variable equilibrium parameter for the interface was considered. It was shown that a...     

Kinetics of metal ion sorption on clinoptilolite

From an investigation into the sorption kinetics of Na⁺, K⁺, and Sr²⁺ ions from standard solutions on finely dispersed clinoptilolite incorporated in a highly permeable inert polyacrylamide gel we have determined the characteristic kinetic size of clinoptilolite and the diffusion coefficients for Na⁺, K⁺, and Sr²⁺ in the clinoptilolite microcrystallites and transport pores. Diagrams have been constructed to enable a valid selection of kinetic models for sorption of the ions from any solutions on clinoptilolite.Institute of Chemistry, Far Eastern Branch of the Russian Academy of Sciences, 690022 Vladivostok. V. I. Vernadskii Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, 117975 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 2, pp. 273–277, February, 1992.     

A Pseudo-Second Order Kinetic Equation for Sorption Processes

Russian Journal of Physical Chemistry A - The problem of substantiating a pseudo-second order equation in the kinetics of sorption processes is considered. A simple way is presented of transforming...     

Mathematical modeling of a sorption process for the retention of acid from a solution

Mechanisms of the formation of additional capacity of sorbent in sorption experiments of nitric acid and the separation of acid and salt in solution are studied using mathematical modeling. A method for the calculation of the dielectric constant and the ratio of concentrations of molecules and electrolyte ions in the inner layer of the sorbent is proposed. A mathematical model is constructed, simulation results are presented, and their comparison with experimental data is performed.