[Preparation of Mo-TiO2/activated carbon and degradation of L-acid under visible light].

The photocatalyst of Mo(6+) doped TiO2 was prepared by a sol-gel method and immobilized to granular activated carbon by coating. The photodegradation of 1-naphthol-5-sulphonic acid (L-acid), and the effects of the loading numbers of the photocatalyst on activated carbon and the light sources on the removal efficiency of L-acid and TOC of solution were investigated. The experimental results show that the Mo(6+) doping can help TiO2 to extend the active scope to the visible-light region. The doped TiO2 supported on activated carbon is anatase with the average particle diameter 17.8 nm. It has been found that the activity of catalyst is reduced with its loading number, and the Mo(6+) doping does not affect the catalyst activity in the ultraviolet region and adsorption of L-acid. The removal efficiency of L-acid and TOC of solution is 57% and 53% respectively when 0.4 g doped photocatalyst is applied in 100 mg x L(-1) L-acid solution illuminated by visible light for 4 hours, while it is 13% and 10% respectively in the case of the undoped photocatalyst. The catalyst can be reused for 4 times to keep the degradation efficiency hardly changed.