Trichloramine formation and decay during breakpoint process [articol]

Abstract

Trichloramine formation and decay in water samples containing chlorine:ammonia mass ratios 10:1 and 12:1 (mg/L:mg/L) at pH=6.0 and 7.0, in the absence and the presence of ketonic compounds, was searched in this paper. From ultraviolet spectra analysis it was determined that trichloramine formation took place in the first seconds after reagents mixing and concentrations from samples containing ketonic compounds were smaller than those from blank samples. NCl3 decay may be described by the first order kinetics law, with constant rates between 6.3-8.1×10-3 min-1 for blank samples, 6.9-8.9×10-3 min–1 in case of samples containing methyl ethyl ketone and 7.8-9.5×10-3 min–1 for those with methyl phenyl ketone. The results revealed that even in conditions of breakpoint process, free chlorine was consumed in some extent in reactions with organic compounds.