两种土壤中对硝基氯苯被Fe~0还原的对比研究

利用零价铁(Fe~0)还原技术修复受对氯硝基苯(p-CNB)污染的土壤,研究常温常压下松砂土和中壤土两种不同土壤的理化性质对还原反应的影响.结果表明:Fe0能有效还原松砂土和中壤土中的p-CNB,生成对应的苯胺化合物,降低毒性;当土壤中p-CNB的含量约为2.5×10~(-6)mol·g~(-1),Fe~0用量为25 mg·g~(-1),反应体系中水分含量为0.75 mL·g~(-1)时,于25℃反应2 h后,松砂土和中壤土中p-CNB的还原率均超过93%;还原反应在中壤土中进行得较快.污染物在土壤中的老化时间对Fe~0还原降解效果影响很小,而土壤粒径、土壤是否灭菌以及土壤有机质含量等因素则对还原有较明显影响;还原降解反应在没有灭菌、有机质含量较高且粒径偏小的壤土中进行得最彻底.

The contrast study on reduction of p-Chloronitrobenzene by Fe~0 in two different soils

In this study, the effects of physical chemical properties of two different soils on the reduction reaction of p-chloronitrobenzene(p-CNB) by zero-valent iron(Fe~0) at ambient pressure and temperature was investigated using Fe~0 reduction technique for remediation of p-CNB contaminated loamy and sandy soils. Results indicated that Fe° was effective in reducing the p-CNB to its corresponding amine in these soils. When the concentration of p-CNB in soils was about 2.5×10~(-6) molg·g~(-1) with soil moisture contents of 0.75 mL·g~(-1) and an Fe~0 application rate of 25mg·g~(-1), after 2 hours of reaction at 25℃, over 93% of p-CNB was reduced in both loamy and sandy soils, and the reduction was faster in the loamy soil. The efficiency of reduction was significantly influenced by such soil factors as sterilization, organic matter contents and mechanical composition, but unaffected by p-CNB aging time in the soils. Laboratory data also demonstrated that a higher soil organic matter contents, non-sterilization of the tested soils, and finer sizes of soil particles tended to promote a complete reduction of p-CNB significantly.