Formation and Stability of mono-, di- and trichloramine in Water Solutions I. Monochloramine

Paper objectives were to determine conditions for monochloramine formation in water solutions, its stability
against time at pH= 6, 7, and 8, for two series of chlorine : ammonia mass ratios (R), 1:1–8:1 and 2 :2–
12:2 (mg/L:mg/L), at 200 C degree. Maximum monochloramine concentrations were recorded for the ratios 3:1 and 4.18:1 in the first minutes after reagents mixing: 1.8-2.3 mg/L (pH = 6.0), 2.4-3.0 mg/L (pH = 7.0), 2.7-3.7 mg/L (pH = 8.0) mg/L. For the second series the maximum concentration, 5.6 mg/L, was recorded at
pH = 7.0 and R= 4.18:1. Due to monochloramine autodecomposition, at 24 hours after reagents mixing for
R = 3:1 and 4.18:1, the following percents from initial concentrations were determined: 60.8-72.2% (pH =
6.0), 80.0-83.3 % (pH = 7.0), 96.2 – 97.2 % (pH = 8). These results are useful to natural water treatment for
drinking purpose.