title: Removal of 2-MIB and geosmin using UV/persulfate: contributions of hydroxyl and sulfate radicals.
abstract: 2-methylisoborneol (2-MIB) and geosmin are two odor-causing compounds that are difficult to remove and the cause of many consumer complaints. In this study, we assessed the degradation of 2-MIB and geosmin using a UV/persulfate process for the first time. The results showed that both 2-MIB and geosmin could be degraded effectively using this process. The process was modeled based on steady-state assumption with respect to the odor-causing compounds and either hydroxyl or sulfate radicals. The second order rate constants for 2-MIB and geosmin reacting with the sulfate radical (SO4(-)) were estimated to be (4.2 ± 0.6) × 10(8) M(-1)s(-1) and (7.6 ± 0.6) × 10(8) M(-1)s(-1) respectively at a pH of 7.0. The contributions of the hydroxyl radical (OH) to 2-MIB and geosmin degradation were 3.5 times and 2.0 times higher, respectively, than the contribution from SO4(-) in Milli-Q water with 2 mM phosphate buffer at pH 7.0. The pseudo-first-order rate constants (ko(s)) of both 2-MIB and geosmin increased with increasing dosages of persulfate. Although pH did not affect the degradation of 2-MIB and geosmin directly, different scavenging effects of hydrogen phosphate and dihydrogen phosphate resulted in higher values of ko(s) for both 2-MIB and geosmin in acidic condition. Bicarbonate and natural organic matter (NOM) inhibited the degradation of both 2-MIB and geosmin dramatically through consuming OH and SO4(-) and were likely to be the main radical scavengers in natural waters when using UV/persulfate process to control 2-MIB and geosmin.
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Pengchao
authors.initials: P
authors.lastname: Xie
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China. Electronic address: majun@hit.edu.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zou
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Siyang
authors.initials: S
authors.lastname: Yue
authors.affiliation: School of the Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China.
authors.forename: Xuchun
authors.initials: X
authors.lastname: Li
authors.affiliation: Civil and Environmental Engineering, Duke University, Durham 27708-0287, USA.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Wiesner
authors.affiliation: School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
authors.forename: Jingyun
authors.initials: J
authors.lastname: Fang
mesh_terms: D000468:Alkalies / Q000737:chemistry; D001892:Camphanes / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D017665:Hydroxyl Radical / Q000737:chemistry*; D007700:Kinetics; D000432:Methanol / Q000737:chemistry; D009284:Naphthols / Q000302:isolation & purification*; D017680:Potassium Compounds / Q000737:chemistry*; D013431:Sulfates / Q000737:chemistry*; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000302:isolation & purification
chemical_list: D000468:Alkalies; D001892:Camphanes; D009284:Naphthols; D017680:Potassium Compounds; D013431:Sulfates; D014874:Water Pollutants, Chemical; C069025:sulfate radical; C005536:2-methylisoborneol; D017665:Hydroxyl Radical; C009007:potassium persulfate; C001278:geosmin; D000432:Methanol
keywords: 2-MIB; Geosmin; Hydroxyl radical; Sulfate radical; UV/persulfate