Heterogeneous photocatalytic oxidation of o-chloroaniline immobilizing on recyclable TiO2

A mixture of sol-gel and commercial TiO2 powder was immobilized on a film to faciliate photodegradation. The photodecay of o-ClA in the mixture of TiO2 sol-gel and powder was about 20% faster then that solely made by the sol-gel solution. The performance of TiO2 film depended on the annealing temperature applied. The transformation of photoactive anatase to rutile phase was observed above 450 °C, which resulted in a slower photodecay of o-ClA. The use of quartz as substrate has proven to be superior to glass in the photoreaction, owing to the excellent optical property of quartz. The o-ClA decay could be further improved by weight increment on the film. A linear relationship between decay rate and weight of coating was acquired. Furthermore, TiO2 coating was found to be dependent on the light intensity. The direct photolysis was determined to be insignificant in the process, while the photocatalytic ability was directly proportional to the amount of TiO2 film coated on the slide. For practical application, the recycling performance of the film was examined. The reuse of the TiO 2 film showed a promising performance with very low variation (±7%) of decay rate after nine consecutive usages. A mathematical model was also proposed to predict the o-ClA removal performance based on the film mass and light intensity.