Pd/TiO2催化剂对三氯生的催化加氢脱氯研究  

Catalytic hydrodechlorination of triclosan over Pd/TiO_2

作　　者：陶善倩[1] 吴可[1] 万玉秋[1] 郑寿荣[1] 

机构地区：[1]污染控制与资源化研究国家重点实验室,南京大学环境学院,南京210046

出　　处：《环境化学》2016年第8期1619-1626,共8页Environmental Chemistry

基　　金：国家科技部973项目(2014CB441103);国家自然科学基金(21277066)资助

摘　　要：采用沉淀-沉积法制备不同载体的Pd负载型催化剂,采用透射电镜(TEM)、X-射线衍射(XRD)和电感耦合等离子体发射光谱(ICP-AES)对材料进行表征;并以所得材料为催化剂对三氯生(TCS)的催化加氢脱氯反应进行了研究.结果表明,Pd/TiO_2型催化剂在TCS加氢脱氯反应中具有较好的效果,反应活性随着Pd负载量的提高而增强.当反应物初始浓度为0.016 mmol·L^(-1),pH值为10,催化剂0.36%Pd/TiO_2用量为20mg时,TCS在70 min可以完成脱氯过程.碱性条件下,p H的升高不利于反应的进行.当催化剂用量在15—25 mg时,催化剂质量标化的反应初活性没有明显变化,表明催化反应过程不受传质阻力的影响.当反应物初始浓度在0.009—0.02 mmol·L^(-1)时,反应初活性随浓度的提高显著增加,但进一步增加反应物的浓度时初活性没有明显提高,因此,TCS在Pd/TiO_2催化剂上的脱氯行为符合Langmuir-Hinshelwood模型,表明TCS的加氢脱氯受表面吸附所控制.催化反应的过程中生成多种脱氯中间产物,反应的最终产物为2-羟基二苯醚.Supported palladium catalysts were prepared by the deposition-precipitation method, and were characterized by TEM, XRD and ICP-AES. The liquid phase catalytic hydrodechlorination of triclosan （TCS） over the catalysts was investigated. Pd/TiO2 catalysts showed good catalytic performance in hydrodechlorination process, and the catalytic activity increased with Pd loading. At initial TCS concentration of 0.016 mmol＂ L-1, pH 10 and catalyst dosage of 50 mg, complete hydrodechlorination of TCS was achieved within 70 min. Under alkaline conditions, increasing pH hindered the reaction. The initial activity normalized by catalysts mass was found to be nearly identical when the amount of catalyst used varied within 15-25 mg, indicative of the absence of mass transport limitations. Finally, the initial activity was markedly enhanced with the initial concentration of TCS when the concentration was in the range of 0.009-0.02 mmol· L-1. While it remained constant with higher initial concentration, reflecting that the catalytic hydrodechlorination of TCS over Pd/TiO2 followed the Langmuir-Hinshelwood model, and the catalytic hydrodechlorination was controlled by TCS adsorption. During the catalytic hydrodechlorination process of TCS, many intermediate products were formed, and the final product was 2-phenoxyphenol.

关 键 词：Pd/TiO2 三氯生 加氢脱氯 沉淀-沉积法 

分 类 号：X52[环境科学与工程—环境工程]