不同形貌的TiO_2材料对五氯苯的热降解  

Thermal degradation of pentachlorobenzene by titania catalysts with different morphologies

作　　者：李宾克 任广军 芦会杰[2] 黄林艳[2] 李倩倩[2] 黄鑫辰 赵彦辉[2] 丁秀华[2] 苏贵金[2] 

机构地区：[1]沈阳工大学环境与化学工程学院,沈阳110159 [2]中国科学院生态环境研究中心环境化学与生态毒理学国家重点实验室,北京100085

出　　处：《环境化学》2015年第12期2213-2222,共10页Environmental Chemistry

基　　金：国家973计划(2015CB453103);国家自然科学基金(21377147,21177141,21321004)资助

摘　　要：采用溶剂热法、均匀共沉淀法和溶胶-水热法分别制备出3种不同形貌的二氧化钛催化剂.采用X射线衍射仪(XRD)、X射线能谱仪(EDX)和场发射扫描电子显微镜(SEM)对催化剂的晶型结构和微观形貌进行分析.以五氯苯为模型污染物,分别在300℃、350℃、400℃条件下对3种不同形貌材料的催化活性进行评价.结果表明,3种材料的活性强弱顺序为:均匀共沉淀法所制TiO_2>溶胶-水热法所制TiO_2>溶剂热法所制TiO_2.均匀共沉淀法所制TiO_2在反应温度350℃、反应时间60 min的条件下对五氯苯的降解效率已经达到99.8%.通过GC-MS对五氯苯的降解产物进行分析,检测到有四氯苯、三氯苯和二氯苯等生成,表明降解反应有加氢脱氯过程发生.五氯苯加氢脱氯降解路径为:Pe CB→1,2,4,5/1,2,3,5/1,2,3,4-Te CB→1,2,4/1,2,3-TrCB→DCB.Three different morphological titania catalysts were prepared by solvothermal, coprecipitation and sol-hydrothermal methods. The materials were characterized by using X-ray diffraction（ XRD）,X-ray energy dispersive spectroscopy（ EDX） and field emission scanning electron microscopy（ FE-SEM）. The catalytic activity of titania catalysts towards pentachlorobenzene（ Pe CB） degradation was evaluated at 300 ℃,350 ℃ and 400 ℃,respectively. The results showed that the activity order was： TiO_2 prepared by co-precipitation method 〉TiO_2 prepared by solhydrothermal method 〉TiO_2 prepared by solvothermal method. The degradation efficiency of Pe CB reached 99.83% over titania catalysts prepared by co-precipitation method,at 350 ℃ for 60 min.The degradation products were determined by gas chromatograph-mass spectroscopy（ GC-MS）.Tetrachlorobenzene（ Te CB）,trichlorobenzene（ Tr CB） and dichlorobenzene（ DCB） was identified as the degradation products,indicating the occurrence of successive reductive hydrodechlorinationreactions during the degradation of Pe CB over the titania catalysts. And the major hydrodechlorination pathway was deduced to be： Pe CB→1,2,4,5 / 1,2,3,5 / 1,2,3,4-Te CB→1,2,4 / 1,2,3-Tr CB→DCB.

关 键 词：二氧化钛催化剂 不同形貌 五氯苯 加氢脱氯 

分 类 号：X505[环境科学与工程—环境工程]