中文摘要：

多环芳烃是一类广泛分布于环境介质中、具有＂三致性＂的有机污染物,随着工业的迅速发展,其在水体中的污染日趋严重。光催化氧化法是去除这一类难降解有机污染物的有效方法。通过氙灯光源模拟太阳光,以不同晶面暴露的TiO2为催化剂,对蒽进行催化降解,研究其在不同晶面占主导的TiO2催化下的光降解机制,分析降解过程中间产物的生成途径。结果表明,蒽的光降解符合一级反应动力学模型,3种晶面占主导的TiO2降解蒽的速率顺序为：{101}〉{010}〉{001},用GC-MS检测到反应过程中的中间产物主要为蒽醌和蒽酮等,剖析了蒽在TiO2催化下的光降解途径,并进一步证实空穴和氧气是影响蒽光催化降解效率的主要活性物质,而·OH对其影响很小,其中{001}晶面暴露的TiO2主要通过表面富集的空穴促进蒽的降解及蒽醌的生成,{101}晶面暴露的TiO2主要通过吸附在其表面的氧气作为电子受体,生成超氧自由基等活性物质,进而氧化去除污染物。

英文摘要：

Polycyclic aromatic hydrocarbons（ PAHs） are toxic and carcinogenic organic pollutants that are ubiquitous in different environmental media. PAH pollution in water is becoming increasingly serious with rapid industrial development. Photocatalytic degradation is an efficient way of removing such persistent pollutants. In this study,anthracene was photocatalytically degraded using anatase TiO2 with different dominant exposed facets as a catalyst under simulated sunlight. The facet-dependent photocatalytic activity and intermediate products formed during the degradation of anthracene were studied. The results demonstrated that the photodegradation of anthracene followed a first-order reaction kinetic model,and the degradation rate of anthracene followed the order{ 101}-TiO2〉 { 010}-TiO2〉 { 001}-TiO2. The photodegradation pathway of anthracene was investigated,and using GC-MS measurements,anthraquinone and anthranone were found to be the main intermediate products formed during the reaction. Holes and oxygen,rather than OH radicals,were confirmed as the main active species in the photodegradation of anthracene. For { 001 }-TiO2,holes generated and accumulated on this facet promote the degradation of anthracene and formation of anthraquinone. In contrast,for { 101 }-TiO2,oxygen absorbed on this facet acts as an electron acceptor and forms superoxide radicals,which then oxidize the pollutants.