Minimizing chlorate ion formation

Abstract

Storage tanks that contain liquod bleach should be periodically flushed and cleaned to minimize buildup of a residual chlorate ion concentration. The treatment of drinking water with either NaOCl or Ca(OCl) 2 is a source of chlorate ion (ClO 3 − ) in finished water. In basic solution, liquid bleach (NaOCl) decomposition is a second‐order process. The decomposition of OCl − involves chlorite ion (ClO 2 − ) as a low‐concentration intermediate. The reaction of ClO 2 − to form ClO 3 − is a fast process, and the ClO 2 − in liquid bleach is at a concentration at least 200 times less than the OCl − concentration. The formation of oxygen from decomposing OCl − is a slower side reaction (<10 percent).