Degradation of organophosphorus pesticides in water during UV/Htreatment: Role of sulphate and bicarbonate ions

The photodegradation of two organophosphorus pesticides,malathian and diazinon,by sulfate radicals and bicarbonate radicals in aqueous solution were studied. the effect of the operational parameters such as ph,salt concentration,water type,hconcentration and initial concentration of pesticides was studied. gas chromatography mass spectroscopy (gcms) was used for analyses of pesticides. when salt effect was studied,it was found that sodium bicarbonate was the most powerful inhibitor used,while sodium sulfate was the weakest one. the highest degradation in uv/hprocess for malathion was found in alkaline condition and for diazinon in acidic condition. the photodegradation in all waters used in this work exhibited first order kinetics. photodegradation rate in distilled water was higher than real water. the degradation of pesticides increased with increasing of hconcentration. © 2012 hindawi publishing corporation.