Formation of halogenated C-, N-DBPs from chlor(am)ination and UV irradiation of tyrosine in drinking water

Chu, Wenhai; Gao, Naiyun; Krasner, Stuart W.; Templeton, Michael R.; Yin, Daqiang

Formation of halogenated C-, N-DBPs from chlor(am)ination and UV irradiation of tyrosine in drinking water

2012

Chu, Wenhai | Gao, Naiyun | Krasner, Stuart W. | Templeton, Michael R. | Yin, Daqiang

The formation of regulated and emerging halogenated carbonaceous (C-) and nitrogenous disinfection by-products (N-DBPs) from the chlor(am)ination and UV irradiation of tyrosine (Tyr) was investigated. Increased chlorine contact time and/or Cl₂/Tyr ratio increased the formation of most C-DBPs, with the exception of 4-chlorophenol, dichloroacetonitrile, and dichloroacetamideChloroform and dichloroacetic acid increased with increasing pH, dichloroacetonitrile first increased and then decreased, and other DBPs had maximum yields at pH 7 or 8. The addition of ammonia significantly reduced the formation of most C-DBPs but increased 4-chlorophenol, dichloroacetonitrile, dichloroacetamide, and trichloroacetonitrile yields for short prechlorination contact times before dosing ammonia. When UV irradiation and chlorination were performed simultaneously, the concentrations of the relatively stable C-DBPs increased, and the concentrations of dichloroacetonitrile, dichloroacetamide, and 4-chlorophenol decreased with increasing UV dose. This information was used to develop a mechanistic model for the formation of intermediate DBPs and end products from the interaction of disinfectants with tyrosine.

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