Abstract
Effect of isocyanuric acid on the stabilization of chlorine was examined in the presence of ammonia. The concentration of added chlorine was changed from 0 to 6 mg/l at the constant ammonia concentration (0.5 mg/l as NH4+), and that of ammonia was changed from 0 to 10 mg/l as NH4+ at the constant concentration of chlorine (1.74 mg/l) added. The added concentration of isocyanuric acid was 0 or 30 mg/l. In these systems exposed to the sun, time course of residual chlorine coucentration was measured at pH 4. Before the break point, chlorine, generally existing in the form of chloramine, was unstabilized by isocyanalic acid. Over the break point, chlorine, almost all existing in the form of free chlorine, was stabilized by isocyanuric acid. These facts seemed to suggest that the bactericidal properties of chlorine are affected by isocyanuric acid.
