Biological, ionizing and ultraviolet radiation and electrochemical degradation of chlorpyrifos pesticide in aqueous solutions

Abstract

Laboratory experiments were carried out on the effect of the electrochemical degradation, biological removal, ultraviolet and ionizing radiation of chlorpyrifos (O,O-Diethyl O-3,5,6-trichloropyridin-2-yl phosphorothioate) as model compounds of insecticides in aqueous solutions. The percentage removal of chemical oxygen demand (COD) measurement during the different treatment showed a significant increase of 64%, 15.66%, 11.84% and 19.12% respectively by electrochemical oxidation at optimized conditions (70 mA.cm­­­­-­­² at 25°C), biological removal by C.metallidurans, ionizing radiation (50 kGy) and UV radiation. The, liquid state 13C-nuclear magnetic-resonance (NMR) confirmed the hydrolysis of the chloropyrifos aliphatic chain after ionizing radiation and UV treatment. The same trend was observed and confirmed by the 1H-NMR. The biological degradation of chloropyrifos by C.metallidurans showed a completely removal of aliphatic chain. This result can be a potential for combined use of electrochemical technique to degr ade the toxic compound to intermediate compound as first step to be next bio-assimilated and eliminated by bacteria.