Radiolytic Reactions of Monochloramine in Aqueous Solutions

Published

September 1, 2003

Author(s)

G A. Poskrebyshev, Robert E. Huie, Pedatsur Neta

Abstract

Monochloramine reacts with hydrated electrons very rapidly, k(NH₂CI + e_aq-) = (2.2 0.2) x 10¹⁰ L mol^-1, to produce oNH₂ radicals. It reacts with oOH radicals more slowly, k(NH₂Cl + oOH) = (5.2 0.6) x 10⁸ L mol^-1 s^-1, to produce oNHCl radicals. While oNH₂ exhibits an absorption peak at 530 nm, ε = 80 L mol^-1 cm^-1, oNHCl exhibits two peaks at 330 nm and 580 nm, ε330 = (85 30) L mol^-1 cm^-1 and ε580 = (56 30) L mol^-1 cm^-1. The oNHCl radical undergoes self-decay and can react also with O₂ to form a peroxyl radical. The equilibrium constant for the reaction oNHCl + 0₂ reversible reaction} NHClO₂ o is estimated to be (3 2) x 10^-3 mol L^-1. Chloramine reacts with the carbonate radical to form a complex [CO₃NH₂Cl] o- with k_f = 2.5 x 10⁵ L mol^-1 s^-1 and k_r = 4 x 10² s^-1, and this complex decomposes with k = 7 x 10² s^-1 to form oNHCl.

Citation

Journal of Physical Chemistry A

Volume

107

Issue

No. 38

Pub Type

Journals

Keywords

chloramines, kinetics, reduction potentials, water treatment

Citation

Poskrebyshev, G. , Huie, R. and Neta, P. (2003), Radiolytic Reactions of Monochloramine in Aqueous Solutions, Journal of Physical Chemistry A (Accessed October 11, 2025)