title: Photodegradation of lambda-cyhalothrin and cypermethrin in aqueous solution as affected by humic acid and/or copper: intermediates and degradation pathways.
abstract: The influence of coexisting humic acids (HA) or Cu²⁺ on the photodegradation of pesticides lambda-cyhalothrin (λ-CHT) and cypermethrin (CPM) in aqueous solution was studied under xenon lamp irradiation. The removal efficiency of pesticides λ-CHT and CPM were enhanced in the presence of either Cu²⁺ or HA but restrained in the presence of both Cu²⁺ and HA. The photodegradation of λ-CHT and CPM followed first-order reaction kinetics. The photodegradation intermediates of λ-CHT and CPM were determined using gas chromatography/mass spectrometry. Possible photodegradation pathways included decarboxylation, ester bond cleavage, dechlorination, and phenyl group removal.
authors: School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, People's Republic of China. xiejm391@sohu.com
authors: Jimin
authors: J
authors: Xie
authors: Pingli
authors: P
authors: Wang
authors: Jun
authors: J
authors: Liu
authors: Xiaomeng
authors: X
authors: Lv
authors: Deli
authors: D
authors: Jiang
authors: Cheng
authors: C
authors: Sun
mesh_terms: D003300:Copper / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D006812:Humic Substances; D007700:Kinetics; D008027:Light; D009570:Nitriles / Q000737:chemistry*; D010575:Pesticides / Q000737:chemistry; D010777:Photochemistry / Q000379:methods; D010782:Photolysis; D011722:Pyrethrins / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry
chemical_list: D006812:Humic Substances; D009570:Nitriles; D010575:Pesticides; D011722:Pyrethrins; D014874:Water Pollutants, Chemical; C017160:cypermethrin; D003300:Copper; C037304:cyhalothrin