Photocatalytic degradation of organic wastes by electrochemically assisted TiO2 photocatalytic system

Photocatalytic degradation of organic wastes with nanosized titanium dioxide particles has been studied for a long time in order to offer an appropriate method for wastewater treatment, but its practical application is greatly limited by the slow process. In this work, an electrochemically assisted TiO2 photocatalytic system was set-up by combining a TiO2 photocatalytic cell with a three-electrode potentiostatic unit. The composite system revealed high photocatalytic activity towards organic wastes mineralization. After continuous treatment for 0.5 h, the maximum absorption of rhodamine 6G (R-6G) was reduced by more than 90%; chemical oxygen demand (COD) and biochemical oxygen demand (BOD5) of textile dye wastewater (TDW) were decreased by 93.9 and 88.7%, respectively. The biodegradability of TDW was also improved because the COD/BOD5 ratio decreased from 2.1 to 1.2. All these results indicated that the composite system could be used for effective organic wastes mineralization or as a feasible detoxification and color removal pretreatment stage for biological post treatment. (C) 2003 Elsevier Ltd. All rights reserved.