Photodegradation of benzene, toluene, ethylbenzene and xylene by fluidized bed gaseous reactor with TiO_2/SiO_2 photocatalysts

摘要

The photodegradation of BTEX (benzene, toluene, ethylbenzene and xylene) in a photocatalytic fluidized bed reactor with TiO_2/SiO_2 was investigated. The TiO_2 film was prepared using the sol-gel method and coated onto silica-gel powder. The effects of the superficial gas velocity and SiO_2 size on the photodegradation of BTEX were examined in a fluidized bed reactor. At steady-state operation, above 79,79,99,98, and 98% removal efficiencies were achieved for benzene, toluene, ethylbenzene, m, p-xylene and o-xylene, respectively, under optimal conditions (2.0 U_(mf) of superficial gas velocity and 1.43 of height/diameter ratio). The reaction product such as CO_2 was detected and intermediate products such as benzaldehyde, malonic acid, acetaldehyde, and formic acid were identified from the photocatalytic reaction. Also, small amounts of benzoic acid and benzyl alcohol were found through analyzing the intermediate species adsorbed on the photocatalysts. The experimental results can lead to the development of an efficient photocatalytic treatment system that utilizes solar energy and TiO_2/SiO_2 photocatalysts.