纳米级Fe_3O_4-Pd/Fe复合材料催化脱氯2,4-D研究  

Catalytic dechlorination of 2,4-D in aqueous solution by nanoscale Fe_3O_4-Pd/Fe composite

作　　者：周红艺 胡蝶 曾思思 陈勇 

机构地区：[1]浙江工业大学环境学院,杭州310014

出　　处：《环境科学学报》2018年第2期518-527,共10页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金(No.20977085);浙江省自然科学基金(No.Y5100211)~~

摘　　要：采用共沉淀法制备纳米级Fe_3O_4,将其包覆在纳米Pd/Fe颗粒表面制成纳米级Fe_3O_4-Pd/Fe复合材料,并用于2,4-二氯苯氧乙酸(2,4-D)的催化脱氯.同时,采用透射电镜(TEM)、扫描电镜(SEM)等方法对复合材料的结构进行分析,并考察了初始pH、钯化率、反应温度、纳米Fe_3O_4投加量等实验参数对n Fe_3O_4-Pd/Fe复合材料催化脱氯2,4-D的影响.结果发现,纳米Fe_3O_4粒径小于Pd/Fe纳米颗粒,具有一定的磁性,包覆于纳米Pd/Fe表面,提高了纳米材料的稳定性及分散性,并有利于复合材料的回收和循环利用.此外,纳米Fe_3O_4具有一定的导电性,可作为良好的电子通道为纳米Pd/Fe颗粒传递电子,促进反应的进行,增强2,4-D的去除效果.实验结果表明,较高的钯化率、反应温度、Fe_3O_4∶Fe质量比及中性pH条件均有利于反应的进行.当纳米Fe投加量为1.0 g·L-1,m(Fe_3O_4)∶m(Fe)为1∶1,初始pH为7.0,钯化率为0.15%,反应温度为25.0℃时,反应90 min后,40.0 mg·L-1的2,4-D的去除率达到100%,苯氧乙酸(PA)的生成率达99.8%.In the present study, Fe3 04 nanoparticles were initially prepared and loaded on nano Pd/Fe surface to form nFe3 04-Pd/Fe, and the synthesized composite was used for catalytic dechlorination of 2, 4-dichlorophenoxyacetic acid （2,4-D） in aqueous solution. This composites were systematically characterized by using Transmission electron microscope （ TEM ）, Scanning electron microscopy （ SEM ）. Operating parameters including initial pH, palladium loading rate, temperature and dosage of Fe304 nanoparticles on 2,4-D reduction were investigated. Results demonstrate that the magnetic Fe3 04 coated on the surface of nanoscale Pd/Fe improved the stability and dispersion capability of nanomaterials. In addition, Fe3 04 served as a good channel for electron transfer from nano Pd/Fe particles and enhanced the removal of 2,4-D. Under the optimized reaction conditions （nFe304 1.0 g·L^-1 ,nFe 1.0 g·L^-1 , T = 25.0℃ , P d/Fe = 0.15%, tr = 200 r·min^-1 , pH = 7.0 ） , 40.0 mg·L^-1 2,4-D was almost completely converted into phenoxyacetic acid（PA） just in 90 min. The findings from this study suggestes that the dechlorination of 2,4-D by nanoscale Pd/Fe was significantly enhanced with Fe3 04 nanoparticles and can be a promising solution for catalytic dechlorination of 2,4-D.

关 键 词：纳米Fe304 纳米Pd/Fe颗粒 2 4-二氯苯氧乙酸 苯氧乙酸 催化脱氯 

分 类 号：X703[环境科学与工程—环境工程]