Photocatalytic treatment of wastewater contaminated with organic waste and heavy metal from semiconductor industry

Abstract

Treatment of dilute-organic wastewater discharged from semiconductor manufacturing facilities using photocatalytic degradation mediated by illuminated TiO2 was experimentally investigated in this study. Two organic solvents, ethyl lactate and phenol was evaluated due to their common applications in various wafer fabrication process. The optimal operating conditions (TiO2 dosage, pH) for the photocatalytic oxidation of ethyl lactate and phenol were determined. Photocatalytic degradation under these optimal conditions was found to be able to simultaneously mineralize those solvents and remove copper (II) in the synthetic wastewater. Under aerobic conditions, oxygen inhibited copper reduction and copper (II) ions were removed through precipitation. In contrast, for reactions under anaerobic conditions, the removal rate of copper (II) ions and the rate of reduction of the organic solvents content are lower than that in the aerobic conditions. Hence the application of photocatalysis in simultaneously reducing copper (II) and the organic solvents content of wastewater discharged from semiconductor industry is worth developing further to improve the efficiency of the reaction.