title: Photodegradation of gemfibrozil in aqueous solution under UV irradiation: kinetics, mechanism, toxicity, and degradation pathways.
abstract: The lipid regulator gemfibrozil (GEM) has been reported to be persistent in conventional wastewater treatment plants. This study investigated the photolytic behavior, toxicity of intermediate products, and degradation pathways of GEM in aqueous solutions under UV irradiation. The results demonstrated that the photodegradation of GEM followed pseudo-first-order kinetics, and the pseudo-first-order rate constant was decreased markedly with increasing initial concentrations of GEM and initial pH. The photodegradation of GEM included direct photolysis via (3)GEM(*) and self-sensitization via ROS, where the contribution rates of degradation were 0.52, 90.05, and 8.38 % for ·OH, (1)O2, and (3)GEM(*), respectively. Singlet oxygen ((1)O2) was evidenced by the molecular probe compound, furfuryl alcohol (FFA), and was identified as the primary reactive species in the photolytic process. The steady-state concentrations of (1)O2 increased from (0.324 ± 0.014) × 10(-12) to (1.021 ± 0.040) × 10(-12) mol L(-1), as the initial concentrations of GEM were increased from 5 to 20 mg L(-1). The second-order rate constant for the reaction of GEM with (1)O2 was calculated to be 2.55 × 10(6) M(-1) s(-1). The primary transformation products were identified using HPLC-MS/MS, and possible photodegradation pathways were proposed by hydroxylation, aldehydes reactions, as well as the cleavage of ether side chains. The toxicity of phototransformation product evaluation revealed that photolysis potentially provides a critical pathway for GEM toxicity reduction in potable water and wastewater treatment facilities.
authors.affiliation: School of Environmental Science and Engineering, Guangzhou Higher Education Mega Center, Guangdong University of Technology, No. 100 Waihuan Xi Road, Panyu District, Guangzhou, 510006, People's Republic of China.
authors.forename: Jingshuai
authors.initials: J
authors.lastname: Ma
authors.affiliation: School of Environmental Science and Engineering, Guangzhou Higher Education Mega Center, Guangdong University of Technology, No. 100 Waihuan Xi Road, Panyu District, Guangzhou, 510006, People's Republic of China. lvwy612@163.com.
authors.forename: Wenying
authors.initials: W
authors.lastname: Lv
authors.affiliation: School of Environmental Science and Engineering, Guangzhou Higher Education Mega Center, Guangdong University of Technology, No. 100 Waihuan Xi Road, Panyu District, Guangzhou, 510006, People's Republic of China.
authors.forename: Ping
authors.initials: P
authors.lastname: Chen
authors.affiliation: School of Environmental Science and Engineering, Guangzhou Higher Education Mega Center, Guangdong University of Technology, No. 100 Waihuan Xi Road, Panyu District, Guangzhou, 510006, People's Republic of China.
authors.forename: Yida
authors.initials: Y
authors.lastname: Lu
authors.affiliation: School of Environmental Science and Engineering, Guangzhou Higher Education Mega Center, Guangdong University of Technology, No. 100 Waihuan Xi Road, Panyu District, Guangzhou, 510006, People's Republic of China.
authors.forename: Fengliang
authors.initials: F
authors.lastname: Wang
authors.affiliation: School of Environmental Science and Engineering, Guangzhou Higher Education Mega Center, Guangdong University of Technology, No. 100 Waihuan Xi Road, Panyu District, Guangzhou, 510006, People's Republic of China.
authors.forename: Fuhua
authors.initials: F
authors.lastname: Li
authors.affiliation: School of Environmental Science and Engineering, Guangzhou Higher Education Mega Center, Guangdong University of Technology, No. 100 Waihuan Xi Road, Panyu District, Guangzhou, 510006, People's Republic of China.
authors.forename: Kun
authors.initials: K
authors.lastname: Yao
authors.affiliation: School of Environmental Science and Engineering, Guangzhou Higher Education Mega Center, Guangdong University of Technology, No. 100 Waihuan Xi Road, Panyu District, Guangzhou, 510006, People's Republic of China.
authors.forename: Guoguang
authors.initials: G
authors.lastname: Liu
mesh_terms: D052918:Environmental Restoration and Remediation; D005663:Furans / Q000737:chemistry; D015248:Gemfibrozil / Q000737:chemistry*; D000960:Hypolipidemic Agents / Q000737:chemistry*; D007700:Kinetics; D010782:Photolysis; D026082:Singlet Oxygen / Q000737:chemistry; D012996:Solutions; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification
chemical_list: D005663:Furans; D000960:Hypolipidemic Agents; D012996:Solutions; D014874:Water Pollutants, Chemical; D026082:Singlet Oxygen; C012986:furfuryl alcohol; D015248:Gemfibrozil
keywords: Gemfibrozil; Kinetics; Mechanism; Photodegradation pathways; Toxicity; UV irradiation