title: Influencing factors and degradation products of antipyrine chlorination in water with free chlorine.
abstract: Owing to its low cost, free chlorine is one of the most common disinfectants for wastewater and drinking water treatment. However, the formation of disinfection byproducts has been found to occur after free chlorine disinfection in recent decades. Antipyrine (ANT), an anti-inflammatory analgesic, has been frequently detected in the aquatic environment. In this work, the removal efficiency of ANT by free chlorine oxidation in ultrapure water was investigated with batch experiments. The influencing factors on the removal of ANT were explored at initial concentrations of ANT from 0.04 to 0.64 mg/L, free chlorine dosage from 0.30 to 1.31 mg/L, and pH from 1.5 to 9.0. The main degradation products were identified by solid phase extraction-gas chromatography-mass spectrometry. The results showed that ANT reacted rapidly with free chlorine in ultrapure water systems and up to 90.6% removal efficiency of ANT was achieved after 25 sec (initial free chlorine 1 mg/L, ANT 0.5 mg/L, pH 7.0). Higher oxidant dosage, lower ANT initial concentration and low pH favor the ANT removal. The main degradation product in ANT chlorination was a monochlorine substitution product (4-chloro-1,2-dihydro-1,5-dimethyl-2-phenyl-3H-pyrazol-3-one), which can be further chlorinated by free chlorine. In addition, the total organic carbon result indicated that ANT is difficult to be mineralized using chlorine.
authors.affiliation: Beijing Key Laboratory for Source Control Technology of Water Pollution, College ofEnvimronmental Science and Engineering, Beijing Forestry University, Beijing 100083, China. cmq1118@126.com
authors.forename: Meiquan
authors.initials: M
authors.lastname: Cai
authors.forename: Liqiu
authors.initials: L
authors.lastname: Zhang
authors.forename: Fei
authors.initials: F
authors.lastname: Qi
authors.forename: Li
authors.initials: L
authors.lastname: Feng
mesh_terms: D000983:Antipyrine / Q000737:chemistry*; D002713:Chlorine / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D054879:Halogenation; D052616:Solid Phase Extraction; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D014874:Water Pollutants, Chemical; D002713:Chlorine; D000983:Antipyrine