Patent ID: 6270675
Filing Date: 2001-08-07
Classification: B01J,C02F

Abstract:
A method for removing dissolved metal from an aqueous stream, comprising:(a) providing a column of weak acid resin, said weak acid resin being in metal-accepting form;(b) passing an aqueous stream containing dissolved metal through said column of weak acid resin, thereby (1) producing an effluent stream having a reduced concentration of dissolved metal, and (2) changing an ever increasing portion of said weak acid resin from metal-accepting form to hydrogen form;(c) measuring the pH of said effluent stream;(d) ceasing to pass said aqueous stream through said column of weak acid resin when said pH of said effluent stream indicates that the amount of hydrogen form weak acid resin has risen to a first level;(e) without regenerating said column of weak acid resin, passing an alkaline solution through said column of weak acid resin, thereby (1) producing a second effluent stream, and (2) changing an ever increasing portion of said weak acid resin from hydrogen form to metal-accepting form;(f) measuring the pH of said second effluent stream;(g) ceasing said passing of said alkaline solution through said column of weak acid resin when said pH of said second effluent stream indicates that the amount of hydrogen form weak acid resin has lowered to a second level; and,(h) repeating steps (b) through (g) a plurality of times.