Photodegradation of alachlor with the TiO(2) film immobilised on the glass tube in aqueous solution

Alachlor photodegradation was performed using TiO(2), which was synthesized by a modified sol-gel method. The thickness of a TiO(2) film immobilised by a 5-time dip-coating was 174 nm and the average diameter of TiO(2) particles was about 10-15 nm in SEM images. The crystal structure of a TiO(2) film calcinated at 300 degrees C for 1 h was observed as a typical anatase type. The stability of a TiO(2) film by a modified sol-gel method was 4% better than TiO(2) by a typical sol-gel method.The removal rate of alachlor with both Fe(3+) and UV radiation in the absence of TiO(2) was 0.28 mg/l/h in 10 h and the removal rate of alachlor with Fe(3+)/UV in the presence of TiO(2) was 0.32 g/l/h, which was higher by 14% than that with Fe(3+)/UV system. TOC concentration during the alachlor degradation with both TiO(2) and UV radiation in the absence of added Fe(3+) decreased from 100%, through 81% and 51%, to 44% with time elapses of 4, 8, and 10 h, respectively, while TOC concentration with both added Fe(3+) and UV radiation in the absence of TiO(2) decreased from 100% to 70% in 10 h.