TITANIUM-DIOXIDE MEDIATED PHOTOCATALYTIC DEGRADATION OF MONOCROTOPHOS

Titanium dioxide mediated photocatalytic oxidation of Monocrotophos (M CP) was studied under different conditions. At a flow rate of 30 ml/mi n and initial concentration of 50 mM, 51% of MCP was found to degrade after an hour. When small amounts of either oxygen or hydrogen peroxid e was added to the system, the degradation was enhanced significantly. Changes in the rates of MCP degradation were studied with the additio n of chloride, chlorate, nitrate, sulphate, and copper ions to the rec irculating solutions. The addition of anions can cause either an incre ase or a decrease in the photocatalytic oxidation of MCP, depending on the type of anions used. Whereas chloride, chlorate, and nitrate were demonstrated to hinder the degradation of MCP, sulphate was found to have an enhancement effect. The behaviour of Cu2+ ions was shown to ha ve different effects on the photocatalytic degradation of MCP. It depe nds on the concentration of Cu2+ ion added during the reaction. At low concentrations (<10(-5) M) an enhancement in the degradation was foun d. However, at higher Cu2+ concentrations, a dramatic lowering of the rate of degradation was observed. Fourier Transformed Infrared Spectro scopy (FTIR) indicated that different intermediates were formed during the photocatalytic oxidation of MCP. These intermediates were also de graded with prolonged reaction.