Photodegradation of acetochlor and butachlor in waters containing humic acid and inorganic ion.

摘要

The photodegradation rates of acetochlor and butachlor in deionized water, river water and paddy water was analysed using HPLC. The effects of humic acids, pH, nitrite, hydrogen peroxide, ferric and manganese ions were also examined. Acetochlor's main adsorption wavelength was less than 280 nm which was similar to butachlor. Photodegradation of acetochlor and butachlor appeared to be caused by adsorption of ultraviolet light less than 280 nm wavelength. The half life of 20 mg acetochlor/litre in air-saturated solution was 6.92 minutes whereas the half life of 20 mg acetochlor/litre in 10 mg hydrogen peroxide/litre was 5.54 minutes. The effect of oxygen was non-significant compared to the air-unsaturated solution. The half lives of 20 mg acetochlor/litre in 10 mg/litre of Fe2(SO4)3, MgSO4 and NaNO2 solutions were 9.07, 9.35 and 9.34 minutes, respectively. The photodegradation rates of acetochlor and butachlor was highest in deionized water and lowest in paddy water.