Photocatalytic decomposition of benzene by UV illumination with the presence of nano-TiO2

Anatase-TiO2 has been successfully coated on the surface of quartz cotton (SiO2) and alumina fibre (Al2O3) by the sol-gel method. The thickness of single layer of TiO2/SiO2 is 1 mu m, while that of TiO2/Al2O3 is 300 nm. The TiO2 crystals are fine with the diameter varied from 20 to 25 nm. The TiO2 crystalline structure is defined by XRD method, and the thickness of the coatings by either XRD or SEM one. Benzene with the concentration of 0.44mg/m(3) can be totally decomposed by TiO2/SiO2 and in about 85% by TiO2/Al2O3 after 8 hours; by increasing UV light (to 40W), the benzene can be completely decomposed after 4.5 hours by TiO2/SiO2 and after 6 hours by TiO2/Al2O3. Thus, TiO2/SiO2 and TiO2/Al2O3 are good materials for fabricating filters to treat hazardous substances in air environment.