%0 Journal Article
%T Hydrolysis and Chlorination of 2,6-Dichloro-1,4-benzoquinone under conditions typical of drinking water distribution systems.
%A Mohan A
%A Reckhow DA
%J Water Res
%V 200
%N 0
%D Jul 2021 15
%M 34038823
%F 13.4
%R 10.1016/j.watres.2021.117219
%X Halobenzoquinones (HBQs) are emerging disinfection by-products (DBPs) that are postulated drivers of bladder carcinogenicity. Prior assessments of 2,6-dichloro-1,4-benzoquinone (DCBQ) occurrence in drinking water distribution systems have revealed a gradual decline with increasing distance from points of entry. While this signals a degradation pathway, there is limited quantitative data on rate of that degradation. A systematic evaluation of DCBQ hydrolysis was performed, resulting in a rate law that is first order in both hydroxide [OH-] and [DCBQ]. The impact of temperature on that rate was characterized according to the Arrhenius relationship. Under the conditions tested (pH~7.2, T = 20°C) chloramine did not significantly impact DCBQ concentrations. However, DCBQ was rapidly degraded in solutions containing free available chlorine (FAC). Kinetic analysis showed non-integer order with respect to FAC. Further investigation led to a model that invoked reaction with dichlorine monoxide (Cl2O) as well as FAC.