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污染控制技术及原理

邓谦,李辛玉,蒋耀辉,彭振山,龙云飞,韦宗元,蔡铁军.Au/γ-Al₂O₃催化剂的制备及其对气相三苯系污染物的催化消除[J].环境科学学报,2008,28(11):2175-2180

Catalytic elimination of benzene series compounds over Au/γ-Al₂O₃ catalysts prepared by deposition-precipitation

摘要：采用沉积-沉淀法制备了负载型Au/γ-Al₂O₃催化剂,对模拟污染气体的三苯系(苯,甲苯,二甲苯)蒸气进行催化消除反应,探讨了金含量、活化条件对催化剂活性的影响.结果表明,负载型Au/γ-Al₂O₃催化剂用量为0.50g、反应气流速为20mL·min^-1时,295℃下可完全催化消除浓度为7.57g·m^-3的苯;在252℃下可完全催化消除浓度为7.49g·m^-3的甲苯;在235℃下能完全催化消除浓度为3.07g·m^-3的二甲苯.苯、甲苯和二甲苯最后都完全矿化为CO₂和H₂O,没有生成新的有机物.对催化反应进行了动力学研究,上述催化反应都是准一级反应.测定得到苯、甲苯和二甲苯催化反应的总包反应表观活化能分别为118.47kJ·mol^-1、101.43kJ·mol^-1和85.18kJ·mol^-1.

Abstract：Supported Au/γ-Al₂O₃ catalysts were prepared by deposition-precipitation for the catalytic elimination of the benzene series(benzene,toluene,dimethylbenzene).The effects of gold loadings,activation temperature and activation time on the activity of the catalysts were investigated.Complete conversion of 7.57g·m^-3 benzene was achieved at 295℃;of 7.49 g·m^-3 toluene at 252℃;and of 3.07 g·m^-3 dimethylbenzene at 235℃ over 0.5 g of catalyst when the flow rate of the feed gas was 20 mL·min^-1.The conversion of toluene remained at 100% after reacting for 45 hours over the Au/γ-Al₂O₃ catalyst.Benzene,toluene and dimethylbenzene were complete mineralized into CO₂ and H₂O,without side-products.The reaction kinetics of elimination of the three benzene series compounds over the supported Au/γ-Al₂O₃ catalysts were determined.The results showed that the catalytic eliminations of benzene,toluene and dimethylbenzene were all quasi-first order reactions,and the apparent activation energies were 118.47 kJ·mol^-1,101.43 kJ·mol^-1 and 85.18 kJ·mol^-1,respectively.