Degradation of Pesticides in Water by Photo Fenton Reaction

Usage of pesticides in plant protection and public health results in pesticide contamination of ground and surface waters. To protect the quality of drinking and surface waters, chemical oxidation is a treatment option. Recoveries of sixteen pesticides of six different groups from spiked (20–800 μg pesticide amounting to 0.2–8.0 ppm in water) samples of water varied from 75 to 99.8%. Generation of hydroxyl radicals (OH^#) in situ by reacting ferrous sulphate with hydrogen peroxide in the presence of UV radiation (photo-Fenton reaction) could degrade herbicides and organophosphorus pesticides from 92 to 100%. Persistent chlorpyrifos insecticide could be degraded up to 92.6%. GC/MS analysis exhibited that the peaks due to atrazine, pendimethalin and metribuzin herbicides disappeared after the treatment of contaminated water. Organochlorines (OCs) could be degraded up to 60–70%, and degradation of synthetic pyrethroids varied. Neonicotinoids analysis by HPLC proved that imidacloprid and thiacloprid could be degraded over 85%. The results hold potential for reducing the amount of multiple pesticides in water.