title: Water temperature significantly impacts the formation of iodinated haloacetamides during persulfate oxidation.
abstract: The use of persulfate oxidation processes is receiving increasing interest for the removal of aquatic contaminants. However, it is unknown whether its application in the presence of iodide has the potential to directly form iodinated DBPs. This study investigated formation of six chlorinated, brominated and iodinated di-haloacetamides (DHAcAms) during persulfate oxidation in the presence of bromide and iodide. Formation of the same DHAcAms during chlorination was monitored for comparison. Persulfate oxidation of natural water formed diiodoacetamide (DIAcAm), and heat-activated persulfate, at 45 °C and 55 °C, generated bromoiodoacetamide (BIAcAm) and dibromoacetamide (DBAcAm), besides DIAcAm. At an ambient iodide concentration of 0.3 μM, total DHAcAms increased slightly from 0.43 to 0.57 nM as the water temperature increased from 4 °C to 35 °C, respectively (only DIAcAm detected), then significantly increased to 1.6 nM at 55 °C (DIAcAm, BIAcAm and DBAcAm detected). Equivalent total DHAcAm concentrations in the presence of 3.0 μM iodide were 0.5, 0.91 and 2.1 nM, respectively. Total DHAcAms formed during chlorination, predominantly dichloroacetamide (DCAcAm) and bromochloroacetamide (BCAcAm), were always significantly higher than that during persulfate oxidation. However, an integrated risk assessment showed the toxicity resulting from the DHAcAms was higher during persulfate oxidation than chlorination. An increase in water temperature from 25 °C to 55 °C significantly increased the integrated toxic risk values for both persulfate oxidation and chlorination. Use of persulfate oxidation should be weighed against the formation of high-toxicity iodinated HAcAms in waters with high ambient iodide concentrations.
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Shanghai 200092, China; Institute of Disinfection By-product Control in Water Treatment, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China. Electronic address: feedwater@126.com.
authors.forename: Wenhai
authors.initials: W
authors.lastname: Chu
authors.affiliation: Institute of Disinfection By-product Control in Water Treatment, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Jianglin
authors.initials: J
authors.lastname: Hu
authors.affiliation: Department of Civil and Environmental Engineering, Imperial College London, London SW7 2AZ, UK.
authors.forename: Tom
authors.initials: T
authors.lastname: Bond
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Shanghai 200092, China; Institute of Disinfection By-product Control in Water Treatment, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Naiyun
authors.initials: N
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Shanghai 200092, China; Institute of Disinfection By-product Control in Water Treatment, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Shanghai 200092, China; Institute of Disinfection By-product Control in Water Treatment, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Daqiang
authors.initials: D
authors.lastname: Yin
mesh_terms: D004203:Disinfection; D054879:Halogenation; D013696:Temperature; D014867:Water; D014874:Water Pollutants, Chemical; D018508:Water Purification
chemical_list: D014874:Water Pollutants, Chemical; D014867:Water
keywords: Advanced oxidation; Drinking water; Haloacetamides (HAcAms); Iodinated disinfection by-products (I-DBPs); Nitrogenous disinfection by-products (N-DBPs); Persulfate