title: [Influential factors and degradation pathway of imidacloprid by homogeneous Co/PMS system].
abstract: Cobaltous-mediated decomposition of peroxymonosulfate (Co/PMS) system is one of novel advanced oxidation technologies (AOTs), which leads to the formation of very strong oxidizing species in aqueous phase. Effects of PMS concentrations, Co2+ concentrations and various inorganic anions (H2PO4-, HCO3-, NO3-, Cl-) on the degradation of Imidacloprid induced by Co/PMS system was investigated as emphasis. The degradation kinetics of imidacloprid followed pseudo first-order kinetics and reaction rates related to PMS and Co2+, concentrations. The reaction rates increased with increasing [PMS] and [Co2+] when the other parameters were constant. However, the decrease of degradation rates was found when the molar ratio of PMS versus imidacloprid was over 20. The effects of H2PO4- had positive effect on the degradation of Imidacloprid, low concentration HCO3- had positive effect and high concentration HCO3- had negative effect, Cl- had negative effect, while NO3- had little effect. Based on the results of GC/MS, two main intermediates were identified, 6-chloronicotinic acid and 6-chloronicotinamide, and the reaction pathway for SO4*- induced by homogeneous Co/PMS was proposed accordingly.
authors.affiliation: Department of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China. chenxiaoyang780509@yahoo.com.cn
authors.forename: Xiao-yang
authors.initials: XY
authors.lastname: Chen
authors.forename: Jing-wen
authors.initials: JW
authors.lastname: Chen
authors.forename: Ping
authors.initials: P
authors.lastname: Yang
authors.forename: Xian-liang
authors.initials: XL
authors.lastname: Qiao
mesh_terms: D002384:Catalysis; D003035:Cobalt / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry*; D007306:Insecticides / Q000737:chemistry; D007700:Kinetics; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D010545:Peroxides / Q000737:chemistry*; D013464:Sulfuric Acids / Q000737:chemistry; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D010545:Peroxides; D013464:Sulfuric Acids; D014874:Water Pollutants, Chemical; C038288:peroxymonosulfate; C082359:imidacloprid; D003035:Cobalt; C033158:sulfuric acid