Abstract: The feasibility of photocatalytic degradation of hexachlorocyclohexane (BHC) in groundwater with titanium dioxide was proved by aseries of experimental investigations. It was shown that the degradation rate of BHC was affected by irradiation time and intensity, groundwater pH and temperature. By means of orthogonal experiment, we have concluded that the optimum degrading conditions are that the radiation time is 30 min, 8 W ultraviolet radiation, groundwater pH=5, temperature is 14 ℃. The best rate of degradation is 47.96%, and the effects of Fe₃₊ and Mn₂₊ on the photocatalytic degradation were investigated through the experiments under the best degrading conditions.

Key words: titanium dioxide, photocatalytic degradation, hexachlorocyclohexane 