零价铁对土壤中对氯硝基苯的还原作用

Reduction of p-chloro-nitrobenzene by zero-valent iron in soil

在常温常压下,利用零价铁(Fe0)还原土壤中的对氯硝基苯(p-CNB),研究反应产物随时间的变化以及反应条件对还原率的影响。实验结果表明,Fe0能够有效将土壤中的p-CNB还原成对氯苯胺(p-CAN),反应过程中先生成中间产物对氯亚硝基苯(p-CNSB),然后再进一步还原生成p-CAN。p-CNB还原率受到反应时间、土壤初始pH、温度、铁粉用量和土壤含水率等条件的影响。当p-CNB约为2.5×10-6mol/g,土壤初始pH为6.8,铁粉用量为50mg,土壤含水率为75%时,在恒温生化培养箱中温度为(25±1)℃条件下,反应5h后p-CNB还原率达到97.43%。

Zero-valent iron （Fe^0） was utilized for the reduction of p-chloro-nitrobenzene （p-CNB） in soil at ambient temperature and pressure. The effects of several parameters on the reaction system as well as the changes of the products were investigated. The results showed that the Fe^0 could reduce p-CNB effectively. GC/MS data revealed that p-CNB was initially reduced to p-chloro-nitrosobenzene （p-CNSB）, which in turn were further reduced to p-chloroaniline （p-CAN）. The reduction efficiency was impacted by time, temperature, the initial pH of the soil, the quantity of Fe^0 and the water content of soil. The efficiency of reduction reached as high as 97.43% after 5 hours reaction at （25±1） ℃, with an initial pH of 6.8 and 75% water content of soil when 50 mg of Fe^0 was added, the initial concentration of p-CNB was 2.5 × 10^-6mol/g.