Enhanced degradation efficiency of toluene using titania/silica photocatalysis as a regeneration process.
Three kinds of titania/silica pellets were prepared using the sol-gel method with surface areas of 50.4 m2 g(-1), 421.1 m2 x g(-1) and 89.1 m2 x g(-1). An annular reactor was designed and built to determine the degradation efficiency of toluene and to investigate the relationship between the adsorption and desorption-photocatalytic processes. Surface area is an important factor influencing the adsorption-photocatalytic efficiency. Higher surface areas of pellets contribute to high rates of conversion of toluene. Un-reacted toluene and reaction intermediates accumulating on their surface deactivated the titania/silica catalyst. To overcome this problem, the adsorption and regeneration process were alternated in a dual reactor system. Connecting or disconnecting the toluene feed gas enabled one reactor to adsorb toluene, while the second reactor was regenerated by photocatalysis. Using UV irradiation and titania/silica pellets with high BET surface area (421.1 m2 x g(-1)), the alternating adsorption/regeneration processes kept the degradation efficiency of toluene at 90% after 8 hours operation. By improving the adsorption-photocatalysis efficiency, and minimising the generation and accumulation of intermediate on the surface of pellets, the method extended catalyst life and maintained a high degradation efficiency of toluene.
Luo
Y
Y
Institute of Sustanability and Innovation, Victoria University, Werribee, Vic 3030, Australia.
Zou
L
L
Hu
E
E
D000327:Adsorption; D000393:Air Pollutants / Q000378:metabolism*; D002384:Catalysis; D008855:Microscopy, Electron, Scanning; D044367:Phase Transition; D010777:Photochemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*; D014050:Toluene / Q000378:metabolism*; D014466:Ultraviolet Rays
D000393:Air Pollutants; C009495:titanium dioxide; D014050:Toluene; D012822:Silicon Dioxide; D014025:Titanium