IMMOBILIZATION OF TIO2 POWDER FOR THE TREATMENT OF POLLUTED WATER

TiO2 powder was immobilised on solid support substrates (stainless ste el, titanium alloy, titanium metal, and tin oxide coated glass) using electrophoretic coating and spray coating. Electrochemical anodisation of titanium metal was also carried out to give a thin film of TiO2 on the surface. The coated substrates were annealed in air at elevated t emperatures to improve the adhesion of the catalyst to the supporting substrates. The photocatalytic efficiency of the TiO2 coatings was com pared using the degradation of phenol in aqueous solution as a standar d test system. In the case of the powder derived films, the photocatal ytic efficiency was found not to be markedly dependent upon either the substrate used or the annealing temperature employed in the coating p rocess. Surface analysis of the immobilised TiO2 showed no significant differences in the elemental composition or in band gap energies. The electrophoretic coating method was found to be the most reproducible resulting in highly fractured thick films with high photocatalytic act ivity. (C) 1998 Elsevier Science B.V.