title: Role of aqueous electron and hydroxyl radical in the removal of endosulfan from aqueous solution using gamma irradiation.
abstract: The removal of endosulfan, an emerging water pollutant, from water was investigated using gamma irradiation based advanced oxidation and reduction processes (AORPs). A significant removal, 97% of initially 1.0 μM endosulfan was achieved at an absorbed dose of 1020 Gy. The removal of endosulfan by gamma-rays irradiation was influenced by an absorbed dose and significantly increased in the presence of aqueous electron (eaq(-)). However, efficiency of the process was inhibited in the presence of eaq(-) scavengers, such as N2O, NO3(-), acid, and Fe(3+). The observed dose constant decreased while radiation yield (G-value) increased with increasing initial concentrations of the target contaminant and decreasing dose-rate. The removal efficiency of endosulfan II was lower than endosulfan I. The degradation mechanism of endosulfan by the AORPs was proposed showing that reductive pathways involving eaq(-) started at the chlorine attached to the ring while oxidative pathway was initiated due to attack of hydroxyl radical at the SO bond. The mass balance showed 95% loss of chloride from endosulfan at an absorbed dose of 1020 Gy. The formation of chloride and acetate suggest that gamma irradiation based AORPs are potential methods for the removal of endosulfan and its by-products from contaminated water.
authors: Institute of Chemical Sciences, University of Swat, Swat 19130, Pakistan; Radiation Chemistry Laboratory, National Centre of Excellence in Physical Chemistry, University of Peshawar, Peshawar 25120, Pakistan. Electronic address: samadchemistry@gmail.com.
authors: Noor S
authors: NS
authors: Shah
authors: Radiation Chemistry Laboratory, National Centre of Excellence in Physical Chemistry, University of Peshawar, Peshawar 25120, Pakistan.
authors: Javed Ali
authors: JA
authors: Khan
authors: Radiation Chemistry Laboratory, National Centre of Excellence in Physical Chemistry, University of Peshawar, Peshawar 25120, Pakistan.
authors: Shah
authors: S
authors: Nawaz
authors: Radiation Chemistry Laboratory, National Centre of Excellence in Physical Chemistry, University of Peshawar, Peshawar 25120, Pakistan.
authors: Hasan M
authors: HM
authors: Khan
mesh_terms: D000085:Acetates / Q000737:chemistry; D002712:Chlorides / Q000737:chemistry; D004583:Electrons; D004726:Endosulfan / Q000737:chemistry / Q000528:radiation effects*; D005720:Gamma Rays; D017665:Hydroxyl Radical / Q000737:chemistry; D010084:Oxidation-Reduction; D012996:Solutions; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000528:radiation effects*
chemical_list: D000085:Acetates; D002712:Chlorides; D012996:Solutions; D014874:Water Pollutants, Chemical; D017665:Hydroxyl Radical; D004726:Endosulfan
keywords: AORPs; Degradation mechanism; Endosulfan; Gamma irradiation; Water treatment