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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TiO_2为催化剂,对蒽进行催化降解,研究其在不同晶面占主导的TiO_2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TiO_2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TiO_2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TiO_2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TiO_2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。
Polycyclic aromatic hydrocarbons (PAHs) are a group of organic pollutants that are widely distributed in environmental media and have “three consistency”. With the rapid development of industry, their pollution in water is becoming more and more serious. Photocatalytic oxidation is an effective method to remove this kind of refractory organic pollutants. The xenon lamp was used to simulate the sunlight and the photocatalytic degradation of anthracene was carried out using TiO 2 exposed by different crystal planes as catalyst. The photodegradation mechanism of anthracene under different TiO 2 photocatalysts under different crystal planes was studied. The formation pathway of intermediates during degradation was analyzed. The results showed that the photodegradation of anthracene was in accordance with the first-order reaction kinetics model. The order of the degradation rate of anthracene was dominated by three crystal planes: {101}> {010}> {001}, and the reaction process was detected by GC- The main intermediates in this study are anthraquinone and anthrone. The photodegradation pathway of anthracene under the catalysis of TiO 2 was analyzed. It was further confirmed that holes and oxygen were the main active substances affecting the photocatalytic degradation efficiency of anthracene. The TiO 2 exposed by the {001} plane promotes degradation of anthracene and anthraquinone mainly through the surface-enriched holes. The TiO 2 exposed by the {101} plane mainly acts as an electron acceptor by the oxygen adsorbed on the surface , Generate superoxide radicals and other active substances, and then oxidation to remove pollutants.