Pd/Fe催化脱氯水中PCE的动力学研究
Dechlorination kinetics of PCE catalyzed by Pd/Fe in water
-
摘要: 以GC-MS为分析方法，采用Pd/Fe双金属对水溶液中四氯乙烯（PCE）进行了催化还原脱氯处理，考察了PCE初始浓度、钯含量、Pd/Fe用量和溶液初始pH值等各因素对脱氯效果影响及还原动力学规律。结果表明，Pd/Fe双金属对PCE有较好的还原脱氯效率，反应遵循准一级反应动力学规律，以反应物PCE 浓度为参照的反应速率常数K变化范围为0.019 min-1～0.16 min-1，对应的PCE半衰期从6 min到36 min，揭示反应有可能是在过量的Pd/Fe双金属表面进行。当PCE溶液初始浓度为1 mmol/L，投加1.2 g钯含量为0.03%的Pd/Fe双金属，在25℃下反应60 min，PCE的脱氯率达到95%以上。增大钯含量和Pd/Fe用量可有效提高脱氯率，在初始pH值为弱酸性条件下有利于还原脱氯反应进行。Abstract: In this study, Pd/Fe bimetal was utilized for the catalytic dechlorination of tetrachloroethene (PCE) in aqueous solution using GC-MS as the analytical method. Reaction factors such as the initial concentrations of PCE, palladium contents of the bimetal, Pd/Fe dosages and the initial pH were examined for their influences on the dechlorination. The reduction kinetics was characterized along with these reaction factors. The results showed that the efficiency of reductive dechlorination of PCE was very good with the Pd/Fe bimetal, and the reaction followed pseudofirst order kinetics. The observed kinetic coefficient K ranged from 0.019 min-1 to 0.16 min-1 with respect to the PCE concentrations, and the halflives of PCE ranged from 6 to 36 minutes, indicating the possibility of reactions occurred on the surfaces of excessive amounts of Pd/Fe bimetals. At an initial PCE concentration of 1 mmol/L , and with 1.2 g of Pd/Fe bimetal containing 0.03% Pd, the rate of dechlorination reached more than 95% after 60 minutes of reaction at 25℃. An increase in the Pd contents of the bimetal or in the dosage of Pd/Fe bimetals was effective in promoting the rates of dechlorination, and initial pH of modest acidity also favored the reductive dechlorination.
-
Key words:
- Pd/Fe bimetal /
- tetrachloroethene (PCE) /
- dechlorination /
- reaction kinetic
-
-
点击查看大图
计量
- 文章访问数: 1643
- HTML全文浏览数: 785
- PDF下载数: 1450
- 施引文献: 0
下载:
