METHOD OF PURIFICATION OF WASTE WATER FROM IONS OF CHROMIUM (III) AND (IV) Russian patent published in 2007 - IPC C02F1/28 B01J20/30 

FIELD: purification of waste industrial water from ions of chromium (III) and (IV).

SUBSTANCE: chromium ions are extracted by sorption at pH from 0.6 to 6.0. Used as sorption materials are modified natural fibrous materials, such as wood saw dust, cellulose, flax stock and shive. Modification includes impregnation of initial material by aqueous solution containing mixture of carbamide and phosphoric acid at 90-95°C for 0.1-1 hour; mass ratio of these components in impregnating solution is equal to (1/2-1) : (1-1/2); then, product is subjected to drying and heat treatment at 140-160°C for 0.3-1 hour and washing for removal of excessive modifying agents to pH equal to 6.0. Proposed method makes it possible to combine stage of removal of ions of chromium (IV) and stage of removal of ions formed during reduction in one stage.

EFFECT: enhanced efficiency.

1 tbl, 3 ex