Generation of iodinated trihalomethanes during chloramination in the presence of solid copper corrosion products.

Copper water pipelines are widely used in water distribution systems, but the effects of solid copper corrosion products (CCPs) including CuO, CuO and Cu(OH)CO on the generation of iodinated trihalomethanes (I-THMs) during chloramination remain unknown. This study found that the formation of I-THMs during chloramination of humic acid (HA) was inhibited by the presence of CuO and CuO, but promoted with the addition of Cu(OH)CO. The negative effect of CuO and CuO is mainly exerted by promoting the decay of both NHCl and HOI. Although Cu(OH)CO also accelerated the decomposition of NHCl and HOI, it was found that the complexes formed between Cu(OH)CO and HA facilitated, through carboxyl functional groups, the reaction between HA and HOI, leading to an enhancement of I-THM generation during chloramination, which was further confirmed by model compound experiments. Additionally, this study demonstrated that the effects of solid CCPs on I-THM generation during chloramination were solid CCP- and HA-concentration dependent, but almost unaffected by different initial I and Br concentrations. This study provides new insights into the health risks caused by the corrosion of copper water pipelines, especially in areas intruded by sea water.