As(lll) Removal from Low-Arsenic Concentration Drinking Water by Coagulation with Quadrivalent Titanium Coagulants

摘要

As(III) removal from low-arsenic concentration drinking water treated by coagulation with mixture titanium tetrachloride and titanium sulfate as coagulants were studied in this paper. Without any pre-oxidation process, the residual concentration of As(III) after treated by the coagulant (concentration of 25mg/L) was less than 4ug/L,which can be satisfied the most rigid guideline for arsenic maximum contaminant level (MCL) proposed by WHO or USEPA. Operated with rapid water dynamics will get the better efficiency for As(III) removal. In the pH range of 3-6 the variation of As(III) removal efficiency was minimal, but the As(III) removal declined gradually with the increase of pH while in the alkaline range. Ferrous salts can significantly increase the efficiency of As(IH) removal by coagulation treatment with mixed titanium salts as coagulant.