Decolorization of colored boiler water and determination of chloride ion by spectrophotometric method

Abstract

In the determination of chloride ion in colored boiler water from low-pressure boilers, the decolorization by coagulation with KAl(SO₄)₂ was a useful pretreatment in the spectrophotometric determination with Hg(SCN)₂ as a reagent. Procedure: To a stirred 50 ml sample, add 3 ml of coagulant {5 w/v% KAl(SO₄)₂· 12H₂O} to form floc. When no floc forms easily, several drops of HNO₃ (5 mol/l) should be added to the sample. Leave the sample for ca. 5 min and filter.