Fe_3O_4稳定化纳米Pd/Fe对水中2,4-D的催化还原脱氯研究  

Catalytic Dechlorination of 2,4-D in Aqueous Solution by Fe_3O_4-Stabilized Nanoscale Pd /Fe

作　　者：周红艺[1] 梁思[1] 曾思思[1] 雷双健[1] 

机构地区：[1]浙江工业大学生物与环境工程学院,杭州310014

出　　处：《环境科学》2013年第11期4311-4318,共8页Environmental Science

基　　金：浙江省自然科学基金项目(Y5100211)

摘　　要：采用四氧化三铁（Fe3O4）稳定化纳米Pd／Fe催化脱氯水溶液中的2，4-二氯苯氧乙酸（2，4-D），获得了良好的处理效果．实验考察了Fe3O4投加量、pH、钯化率、温度、搅拌速率等因素对2，4-D去除的影响．2，4-D去除率随Fe3O4投加量增加而提高，投加量为4．0g·L-1时，反应210min后，2，4-D去除率为93．5％，而未稳定的纳米Pd／Fe，去除率为47．3％．低pH可促进2，4-D还原脱氯，pH为2．6-4．1时，2，4-D在110min内几乎完全去除．2，4-D去除率随钯化率增加而提高．随着钯化率由0．25％、0．50％增加到0．75％，210min后，2，4．D的去除率也由51．4％、93．5％提高到99．9％．温度在16．5-30．0℃范围内，反应210min后，2，4-D去除率均可超过90．0％．温度升高到35．0、40．0℃时，去除率显著下降．2，4-D去除率随着搅拌速率加快而提高．Fe3O4的加入可以使纳米Pd／Fe分散和稳定．此外，Fe0可通过Fe3O4将电子传递给H＋和2，4-D，促进2，4-D的还原脱氯．Fe3 O4-stabilized nanoscale Pd/Fe was used to dechlorinate 2,4-D in aqueous solution and achieved high dechlorination efficiency. The Fe3O4 dosage, pH, Pd loading, temperature and stirring rate were important factors for dechlorination of 2,4-D. The removal rate of 2,4-D increased with the increase of Fe30a dosage, and it reached 93.5% after 210 min when the Fe3O4 dosage was 4.0 g.L-1 , while only 47.3% 2,4-D was transformed using bare nanoscale Pd/Fe. Low pH enhanced deehlorination and 2,4-D was almost completely dechlorinated within 110 min when the pH ranged from 2. 6 to 4. 1. The deehlorination efficiency was significantly influenced by Pd loading. After 210 rain, the different Pd loading, 0.25%, 0.50% and 0.75%, resulted in 2,4-D reduction efficiency of 51.4% , 93.5% and 99.9% , respectively. The removal rate was higher than 90. 0% after 210 min in the temperature range of 16.5℃ to 30.0℃ , while it decreased significantly when the temperature rose to 35.0 and 40.0℃. The deehlorination efficiency was improved with the increasing stirring rate. Fe304 prevented the aggregation of nanoscale Pd/Fe particles. In addition, Fe3O4 acted as a medium to promote the electron transfer from Fe＋ to H ＋ and 2,4-D, and thus enhanced the reductive dechlorination of 2.4-D.

关 键 词：四氧化三铁 稳定化 纳米Pd FE 2  4-D 脱氯 

分 类 号：X52[环境科学与工程—环境工程]