A study on deactivation and regeneration of titanium dioxide during photocatalytic degradation of phthalic acid

The cause of deactivation of Degussa P25 titanium dioxide (TiO2) during photocatalytic degradation of phthalic acid in aqueous medium was investigated. Various regeneration methods, such as washing with solvents, hydrogen peroxide (H2O2) and thermal treatment were attempted to find the best technique for regeneration of spent catalyst. The deactivation and regeneration of TiO2 was monitored using XRD, FTIR, CHNO analysis, zeta potential measurement and surface area analysis. The surface adsorption of phthalic acid and the reaction intermediates deactivates the catalyst. The regeneration by H2O2 treatment nearly restored the activity, whereas washing with solvents and thermal treatment showed poor regeneration.