Surface modification and immobilization of the photocatalyst titanium dioxide

Photocatalytic degradation of organic pollutants in titanium dioxide (TiO{dollar}sb2{dollar}) aqueous suspensions has been a subject of great interest. In this study, the possibility to improve the TiO{dollar}sb2{dollar}/UV process was investigated. Two aspects of the degradation system were selected for improvement: the enhancement of the catalyst efficiency with metal ion doping and the immobilization of the TiO{dollar}sb2{dollar} onto the reactor surface.; Three processes of metal impregnation onto the TiO{dollar}sb2{dollar} surface were investigated. It was observed that adsorption of metal ions onto rutile TiO{dollar}sb2{dollar} inhibited its photoactivity. An inhibitory result was also observed when metal ions were co-precipitated with this catalyst during its preparation. Photodeposition of metal ions onto anatase TiO{dollar}sb2{dollar} exhibited the best procedure to enhance the catalyst efficiency in terms of phenol degradation. An improvement of up to 70% was observed using Ag/TiO{dollar}sb2{dollar} when compared to pure TiO{dollar}sb2{dollar}.; The photodegradation process was also improved by an effective TiO{dollar}sb2{dollar} immobilization procedure. For the coating process, an irregular glass surface was first coated with colloidal TiO{dollar}sb2{dollar}. A second coating solution containing commercially available TiO{dollar}sb2{dollar} was then applied. This coated reactor showed a considerably high organic degradation efficiency.; The degradation of several chlorophenols were studied using the same TiO{dollar}sb2{dollar}-coated reactor. Since the catalyst could be efficiently coated onto the glass surface, the necessary step to remove TiO{dollar}sb2{dollar} from suspension could be eliminated. Best of all, its possible reuse with no substantial decrease in its photoactivity makes the use of the TiO{dollar}sb2{dollar} coated reactor a very attractive alternative for the removal of hazardous organic compounds from aqueous systems.