零价铁对土壤中2-氯硝基苯的还原作用

在常温常压下利用零价铁(Fe0)还原土壤中的2-氯硝基苯(o-CNB),研究反应条件对还原率的影响以及反应产物在不同反应阶段的变化.GC-MS检测结果显示,o-CNB在还原过程中先生成2-氯亚硝基苯,最终生成2-氯苯胺.反应时间、Fe0用量、温度和土壤初始pH值等均会对o-CNB的还原率产生影响,其中土壤初始pH值控制在偏酸性、土壤温度较高时能显著提高其还原率.当o-CNB的初始浓度约为2.5×10-6 mol/g,Fe0加入量是25 mg/g时,经过4 h反应,o-CNB的还原率可达99%以上.此外,还初步探讨了Fe0还原o-CNB的反应机理.

Reduction of 2-chloronitrobenzene by Fe0 in soils

The reduction of 2-chloronitrobenzene (o-CNB) in soils by Fe⁰ at ambient temperature and pressure was studied. The effects of several parameters of the reaction system as well as the changes of the reaction products with time were investigated. Results from GC-MS analyses of the samples indicated that o-CNB was initially reduced by Fe⁰ to 2-chloro nitrosobenzene, and finally to 2-chloroaniline. The reaction time, the quantity of Fe⁰, and the initial soil pH all had some impacts on the reduction of o-CNB by Fe⁰. An acidic soil pH and a higher temperature seemed to promote more reduction of o-CNB. After 4 hours of reaction, the efficiency of the reduction reached 99% when 25 mg of Fe⁰ per gram of soil was added and the initial concentration of o-CNB was 2.5×10^-6mol/g. In addition, preliminary mechanisms of the reduction reaction were discussed briefly.