SO2-4/TiO2-SiO2的制备及光催化降解苯酚

引言纳米TiO2与太阳能技术结合处理、净化污水被认为是21世纪最具应用前景的绿色环保技术[1],但迄今纳米TiO2制备工艺繁杂、成本昂贵,难以推广,加之TiO2本身的光生电子-空穴复合率较高,其表面改性成为热门研究课题之一.文献表明,在对乙烯的光催化降解研究中,用TiO2-SiO2复合体显著好于单纯的TiO2[2],用SO2-4表面修饰纳米TiO2在光催化分解溴代甲烷、苯等时表现出优异的光催化特性[3,4],但同样存在所用原料昂贵、成本居高不下的缺点.另外就酚水处理而言,生物法虽然投资少,但处理苯酚时效果欠佳[5].

PREPARATION OF SO2-4/TiO2-SiO2 COMPLEX CATALYSTS AND ITS PHOTOCATALYTIC PROPERTIES IN DEGRADATION OF PHENOL

Ultra fine SO^2-₄/TiO₂-SiO₂ complex catalysts were synthesized by the one-step calcination method，which used titania sulfate and white carbon as raw materials and polyvinyl alcohol as dispersing agent. Catalysts are characterized by XRDIRTDA and BET. Different preparation factors were discussed.The catalysts consisting of SO₂-43.4% and TiO₂∶SiO₂=1∶6 showed excellent reaction activity and stability for the photocatalytic degradation of phenol.Controlling calcination temperature and time (450 ℃,2 h) could avoid or diminish the formation of Ti-O-Si bond and obtain higher Vg and better dispersivity of TiO2 on the surface of SiO2.The kinetic study on photocatalytic degradation of phenol with the complex catalysts in a suspension system under 40 W UV-lamp showed that apparent rate constant k conformed to a zero-order kinetic model at initial concentration <100 mg&#8226;L-1 and increased with increasing pH value of phenol solution up to pH=12.When pH=10, k=3.32×10-1 mg&#8226;L-1&#8226;min-1. Solar photocatalytic experiment also gave good results.