Photocatalytic degradation of rhodamine B catalyzed by TiO 2 films on a capillary column.

TiO 2 films on a capillary column were prepared using tetrabutoxytitanium as a source of TiO 2 via the sol-gel method. The film thickness showed a linear increase with tetrabutoxytitanium concentration. The specific surface area of the film was improved by adding polyethylene glycol with different molecular weights. Under optimal conditions, the prepared film had a good mesoporous structure with specific surface area of 47.72 m 2 g -1 , and showed nearly spherical nanoparticles with a 10 nm diameter and anatase phase. Influences of the thickness, specific surface area, and initial solution concentration on photodegradation of rhodamine B using TiO 2 films as a catalyst were investigated. The results showed that the photodegradation efficiency increased with an increasing thickness and specific surface area of TiO 2 films. For a rhodamine B solution of 15 mg L -1 , the photodegradation efficiency was 98.33% in 30 min under the optimal conditions. The catalysts could be reused up to eight times with almost the same efficiency, indicating a firm immobilization of films on the inner wall of the capillary. Therefore, TiO 2 films are promising for the treatment of wastewater.