title: Degradation mechanisms of geosmin and 2-MIB during UV photolysis and UV/chlorine reactions.
abstract: We conducted chlorination, UV photolysis, and UV/chlorin reactions to investigate the intermediate formation and degradation mechanisms of geosmin and 2-methylisoborneol (2-MIB) in water. Chlorination hardly removed geosmin and 2-MIB, while the UV/chlorine reaction at 254 nm completely removed geosmin and 2-MIB within 40 min and 1 h, respectively, with lesser removals of both compounds during UV photolysis. The kinetics during both UV photolysis and UV/chlorine reactions followed a pseudo first-order reaction. Chloroform was found as a chlorinated intermediate during the UV/chlorine reaction of both geosmin and 2-MIB. The pH affected both the degradation and chloroform production during the UV/chlorine reaction. The open ring and dehydration intermediates identified during UV/chlorine reactions were 1,4-dimethyl-adamantane, and 1,3-dimethyl-adamantane from geosmin, 2-methylenebornane, and 2-methyl-2-bornene from 2-MIB, respectively. Additionally, 2-methyl-3-pentanol, 2,4-dimethyl-1-heptene, 4-methyl-2-heptanone, and 1,1-dichloro-2,4-dimethyl-1-heptane were newly identified intermediates from UV/chlorine reactions of both geosmin and 2-MIB. These intermediates were degraded as the reaction progressed. We proposed possible degradation pathways during the UV photolysis and UV/chlorine reactions of both compounds using the identified intermediates.
authors: Department of Environmental Health Sciences, School of Public Health, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea.
authors: Tae-Kyoung
authors: TK
authors: Kim
authors: Department of Environmental Health Sciences, School of Public Health, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea.
authors: Bo-Ram
authors: BR
authors: Moon
authors: Department of Environmental Health Sciences, School of Public Health, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea.
authors: Taeyeon
authors: T
authors: Kim
authors: Department of Environmental Health Sciences, School of Public Health, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea.
authors: Moon-Kyung
authors: MK
authors: Kim
authors: Department of Environmental Health Sciences, School of Public Health, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea. Electronic address: zohkd@snu.ac.kr.
authors: Kyung-Duk
authors: KD
authors: Zoh
mesh_terms: D001643:Bridged Bicyclo Compounds / Q000032:analysis / Q000528:radiation effects; D001892:Camphanes / Q000032:analysis* / Q000528:radiation effects; D002713:Chlorine / Q000737:chemistry*; D002725:Chloroform / Q000032:analysis / Q000528:radiation effects; D054879:Halogenation; D007659:Ketones / Q000032:analysis / Q000528:radiation effects; D007700:Kinetics; D009284:Naphthols / Q000032:analysis* / Q000528:radiation effects; D010782:Photolysis; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000528:radiation effects; D018508:Water Purification / Q000379:methods*
chemical_list: D001643:Bridged Bicyclo Compounds; D001892:Camphanes; D007659:Ketones; D009284:Naphthols; D014874:Water Pollutants, Chemical; C005536:2-methylisoborneol; C082069:bornylene; D002713:Chlorine; D002725:Chloroform; C011917:2-heptanone; C001278:geosmin
keywords: 2-Methylisoborneol (2-MIB); Chlorination; Geosmin; Intermediate; Kinetics; Photolysis