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

Abstract The cause of deactivation of Degussa P25 titanium dioxide (TiO 2 ) during photocatalytic degradation of phthalic acid in aqueous medium was investigated. Various regeneration methods, such as washing with solvents, hydrogen peroxide (H 2 O 2 ) and thermal treatment were attempted to find the best technique for regeneration of spent catalyst. The deactivation and regeneration of TiO 2 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 H 2 O 2 treatment nearly restored the activity, whereas washing with solvents and thermal treatment showed poor regeneration.