钯/聚合物复合催化膜制备及催化还原对硝基苯酚

Preparation of palladium /polymer composite catalytic membranes and application in catalytic reduction of 4-nitrophenol

钯金属具有较高的催化加氢性能,钯催化还原降解水体中污染物的研究一直是国内外研究的热点。为了制备催化性能稳定、催化活性高且易于回收利用的Pd催化剂,实验以聚丙烯腈(PAN)聚合物分离膜作为基材,采用层层自组装方法将聚乙烯亚胺/钯配合物(PEI-Pd(II))和聚苯乙烯磺酸钠(PSS)交替组装在基膜表面,制备了(PEI-Pd(0)/PSS)n复合催化膜,并采用膜分离装置通过对硝基苯酚催化加氢反应来评价催化膜的催化性能。实验结果表明,荷电化处理时间、NaOH溶液浓度、PEI和Pd(II)摩尔比、自组装层数影响着膜的催化性能。当荷电化处理时间为1.5 h,NaOH溶液浓度为1.5 mol/L,PEI和Pd(II)摩尔比为60∶4,自组装层数为5层时,复合催化膜有最佳的催化性能,其对对硝基苯酚的去除率能达到90%以上。

Catalytic reduction of water contaminants using（ Pd）-based catalysts has been extensively studied due to its high efficiency of catalysis hydrogenation. In order to obtain membrane supported catalysts with high stability,high catalytic activity and easy to recycle,palladium/polymer catalysis composite membrane was synthesized by layer-by-layer deposition of PSS and PEI-Pd（ II） on PAN membrane and subsequent reduction of Pd2＋ to Pd0. Through the catalytic reduction of 4-nitrophenol with KBH4 in the membrane separation device,the catalytic performance and influencing factors of preparation of composite catalytic membrane were studied. Experiment results indicated that the catalytic performance of membrane was affected by the time of hydrolysis in NaOH solution,the concentration of NaOH solution,the ratios of PEI to Pd（ II） and number of bilayers. When time of hydrolysis was 1. 5 h,concentration of NaOH was 1. 5 mol/L,molar ratios of PEI to Pd（ II） was 60∶ 4 and bilayers number was less than 5,composite catalytic membrane had high catalytic performance. The removal rate of 4-nitrophenol was maintained above 90%.