Haloacetamides (HAcAms) are an emerging class of nitrogenous disinfection by-products (N-DBPs) with high cytotoxicity and genotoxicity, which are widely detected in drinking water. The toxicity of trichloroacetamide (TCAcAm) is significantly higher than traditional DBPs. In this study, ultraviolet (UV) treatment was combined with sodium sulphite (Na2SO3) to remove TCAcAm from water. The effects of different light intensities, different agent dosages (Na2SO3), and pH conditions on the removal of TCAcAm by UV/Na2SO3 advanced reduction process were investigated. The results showed that TCAcAm could be rapidly degraded by the UV/Na2SO3 system. The degradation effect was directly proportional to light intensity, dosage of Na2SO3, and pH. Moreover, the pH had a significant effect on the reaction rate and degradation rate. As the pH increased from 6 to 9, the degradation rate of TCAcAm increased from 12.8% to 99.6%, in 120 min. The removal rate of TCAcAm reached 99.4% when the UV light intensity, pH, Na2SO3 dosage, and reaction time were 450 μW·cm-2, 9, 1.00 mmol·L-1, and 30 min, respectively. The experimental results indicated that the UV/Na2SO3 system is an efficient advanced reduction process for the removal of TCAcAm, and it has the potential to reduce other halogenated DBPs. Therefore, it could be used for the degradation of halogenated DBPs in the treatment of drinking water.
Keywords: advanced reduction; dosage; light intensity; pH; sodium sulfite; trichloroacetamide.