Reductive dechlorination of haloacetamides in drinking water by Cu/Fe bimetal

Haloacetarnides (HAcAms), a class of highly toxic nitrogenous disinfection by-products (N-DBPs), have been widely detected in drinking water. The control of DBPs is an important measure to ensure the safety of drinking water. Due to the presence of residual chlorine and organic compounds that failed to be effectively removed, HAcAms could be formed in the finished drinking water distribution systems. In the study, Cu/Fe bimetal with different molar ratios of Cu to Fe was synthesized. This study reported that Cu/Fe bimetal reduced trichloroacetamide (TCAcAm) to dichloroacetamide (DCAcAm) and monoacetamide (MCAcAm), and the reduction ability of Fe was greatly improved due to the incorporation of Cu. The optimal HAcAm removal was achieved when the molar ratio of Cu to Fe was 2.0%, Cu/Fe bimetal could reach complete degradation of TCAcAm within 1 h. With the increase of Cu/Fe bimetal dose or the decrease of solution pH, the reduction ability of Cu/Fe bimetal for HAcAm removal also increased. The calculated integrated toxicity values from HAcAms, which was used to reflect the comprehensive control effect of Cu/Fe bimetal for HAcAms, were also reduced with the decrease of solution pH and the increase of bimetal dose. The release of Cu2+ was not detected during the whole treatment process, Cu/Fe bimetal may be an excellent material for controlling DBPs as the end- control methods in tap water.