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UDC 628.16.081:546.72/.711

Ryazantsev A. A., Glazkov D. V., Prosianikov E. D.

Removal of iron and manganese from natural water

Summary

The task of the study was investigating the impact of cavitation originating in low pressure devices of jet type on the kinetics of Fe²⁺ and Mn²⁺ ions oxidation as well as developing the method of chemical free removal of manganese and iron from natural water. The results of studies and the mechanisms of iron Fe²⁺ and manganese Mn²⁺ catalytic oxidation in water induced by cavitation are presented. The jet type device is equipped with a cartridge made in the form of a cone charged with crushed natural manganese mineral psilomelane or small steel chips. The particles of MnO₂ and (or) FeOOH catalyst getting into water as a result of corrosion of the charge under the impact of cavitation become centers on which a Fe²⁺ and Mn²⁺ ions adsorption and oxidation take place. It was stated that under these conditions Fe²⁺ oxidation was not a limiting stage whereas complete oxidation of Mn²⁺ ions with the initial concentration of 2 mg/l occurs within 5 minutes. The fast manganese oxidation in the reactor charged with steel chips is caused by high Fe⁰ corrosion rate induced by cavitation and catalytic effect of structureless iron hydroxides that are formed during the charge corrosion. The obtained experimental data allowed designing a process flow scheme of manganese and iron removal from water that included a cavitation module and ceramic membrane filters operating in cross-filtration mode. The dimensions and size of a water treatment unit with a capacity of 60 m³/day have been calculated.

Key words

iron , manganese , natural water , demanganization , deferrization , catalytic oxidation , cavitation , cross-filtration