Mylyanuk O. Ecologically safe adsorption effluent treatment from ions of copper and chromium

The dissertation is devoted to the removal of heavy metal ions from wastewaters of industrial enterprises by means of natural zeolites in order to ensure the ecological safety of water bodies. In this paper, the characteristics of natural zeolite, given its physical and chemical properties, crystal structure of zeolite, ion exchange and sorption properties. Fractional division was done and the average diameter of the grains of zeolite was determined. Physicochemical and toxicological properties of two metals, copper and chromium are shown. Static activity was determined and adsorption isotherm for copper and chromium ions for their single and simultaneous presence in solution were built. The isotherm of sorption for the Сu2+ was described by the equation of the Langmuir isotherm. The obtained dependences indicate a high selectivity for copper ions in the region of low concentrations. According to the type of the curve, the isotherm for Cr6+ can be attributed to the isotherm S-like appearance, which belongs to the isotherm of type II, which indicates the continuation of adsorption after the formation of a monomolecular adsorption layer. By analyzing the results of the experimental studies on the coherent adsorption of copper and chromium ions, it has 21 been established that the copper ions were significantly better absorbed by the sorbent compared to chromium ions. Study of adsorption kinetics of Cu2+ ions made it possible to establish the mechanism of sorption which determinates by the diffusion of Cu2+ ions to the surface of the zeolite grain (the external diffusion region) and the transport of ions inside the pores and channels (the internal diffusion region). By using the basic mass transfer equation, coefficients of mass transfer have been determined. The determination of effective coefficients of internal diffusion was based on the experimental results and a theoretical model based on the differential equation of molecular diffusion with boundary conditions of the first kind. The dynamics of adsorption for different heights of adsorbent layer for certain components of monpropellant solution and of two-component system wich containes copper and chromium ions was investigated. An approximated Thomas model has been used to describe the adsorption dynamics, by means of which the process in a short layer may be described using the exponential dependence. A fundamental technological scheme of chromatographic separation of the binary system which containes copper and chromium ions in aqueous solution was proposed. The method of sequential adsorption by application of copper-exchanged zeolite to adsorb of phosphate compounds got its further development.