Applied studies on immobilized titanium dioxide films as catalysts for the photoelectrochemical detoxification of water

Preliminary results are presented on the photochemical and photoelectrochemical degradation of aqueous organic solutions by anodic, thermal and sol-gel TiO₂ films. The films were tested in a photochemical falling film reactor, and a photochemical/photoelectrochemical vortex reactor, and preliminary results are presented on the degradation of a range of model organics using these reactors. The former showed the best mass transport characteristics and most efficient light usage, whilst the latter reactor clearly showed the efficacy of the electric field enhancement effect. The results on the vortex reactor effectively represent a proof-of-concept of the electric field enhancement approach in large scale photoelectrochemical reactors. From time to time it is necessary to recoat the substrates, and the importance of the procedure adopted to remove 'old' TiO₂ films prior to the fabrication of 'new' films is highlighted, as well as the mode of operation of the sol-gel films, and problems encountered in reactor design.