1,2-二氯乙烷在Co_(x)Ti_(1-x)氧化物上的催化降解性能

Catalytic degradation of 1,2-dichloroethane on Co_(x)Ti_(1-x) composite oxides

随着工业和经济的快速发展,含氯挥发性有机化合物(CVOCs)排放量日益增多,对人体健康以及环境造成严重危害。催化燃烧法是治理CVOCs最有效和经济的方法之一。本文采用溶胶-凝胶法制备出了不同Ti掺杂量的Co_(x)Ti_(1-x)复合氧化物,并对其物理化学性质进行了表征。研究了Co_(x)Ti_(1-x)催化剂对1,2-二氯乙烷(1,2-DCE)的催化氧化性能。结果表明,当Ti掺杂量低于0.6时,Co_(x)Ti_(1-x)复合氧化物呈现非晶相结构,形成无定形结构的Co-O-Ti固溶体。Ti元素的掺杂增加了Co_(x)Ti_(1-x)复合氧化物的表面酸位点及吸附态氧含量。其中,Co_(0.8)Ti_(0.2)催化剂具有较大的比表面积、良好的氧化还原性能、丰富的表面吸附态氧及中强酸位点,对1,2-DCE表现出较高的催化氧化能力;在气时空速为20000mL/(g·h)、1,2-DCE浓度为4060mg/m^(3)的条件下,其对1,2-DCE的转化率达90%时所需温度为318℃。此外,在380℃长时间运行时,Co_(0.8)Ti_(0.2)也显示出较好的稳定性。

With the rapid development of industry and economy,the increasing emission of chlorinecontaining volatile organic compounds(CVOCs)have caused serious harm to human health and environment.Catalytic combustion is one of the most effective and economical methods to treat CVOCs.Co_(x)Ti_(1-x) composite oxides with different Ti loading were prepared by sol-gel method,their physical and chemical properties were characterized and the catalytic performance for 1,2-dichloroethane(1,2-DCE)degradation was investigated.The results showed that the Co_(x)Ti_(1-x) composite oxides formed amorphous Co-O-Ti solid solution when Ti loading was less than 0.6.The addition of Ti increased the surface acid sites and the adsorbed oxygen content for the prepared Co_(x)Ti_(1-x) catalysts.Among them,Co_(0.8)Ti_(0.2) had large specific surface area,good redox performance,abundant surface adsorbed oxygen and medium-strong acid sites,and hence showed high catalytic oxidation ability for 1,2-DCE.When the gas space-time velocity was 20000mL/(g·h)and the concentration of 1,2-DCE was 4060mg/m^(3),the temperature required for 90% conversion of 1,2-DCE was 318℃.Besides,Co_(0.8)Ti_(0.2) also exhibited good stability at 380℃ in long-time runs.