Water treatment using nano-crystalline TiO2 electrodes

The photocatalytic and electrochemically assisted photocatalytic degradation of formic acid was investigated in an one-compartment photoelectrochemical cell incorporating nano-crystalline TiO2 electrodes prepared by the immobilisation of Degussa P25 on tin oxide coated glass. The application of +1.0V (SCE) to the TiO2 electrode resulted in a marked increase in the rate of formic acid degradation under anaerobic and air sparged conditions as compared to the open circuit electrode. When the solution was sparged with O-2 the application of a positive bias did not result in a major increase in the rate. A second cathode compartment was added to the cell for the simultaneous photocatalytic oxidation of formic acid and the recovery of copper ions from solution. Formic acid was degraded at the TiO2 photoanode and copper metal was recovered at the copper mesh cathode with a high efficiency. (C) 2002 Elsevier Science B.V. All rights reserved.