Abstract
Dimethoate is an organophosphorous insecticide used to control a variety of insects in
agricultural productions. The contamination of water by dimethoate and other
organophosphate insecticides represents a great hazard to the humans and animals due to
carcinogenic effect and other toxic effects on nerve system. To remove dimethoate
contamination from water, photocatalysis has been applied as a powerful method. Powder
form of some selected metal oxides such as TiO2, Al2O3, Fe2O3, and MgO were used.
Photocatalytic decomposition of dimethoate at different conditions (dimethoate initial
concentration, catalyst type and catalyst concentration, temperature, and presence of oxidant)
was investigated in a batch reactor. Oxidants such as H2O2, K2S2O8, and (NH4)2S2O8 were
used. Amongst the tested oxides, TiO2 achieved the best decomposition efficiency of
dimethoate and the decomposition increased as the concentration of TiO2 increased up to 100
mg/l. Addition of H2O2 to reaction system highly enhanced the decomposition process.