难降解石油烃污染土壤机械化学修复及机理研究

Mechnochemical (MC) method is a new technology to treat non-degradable organic waste and contaminated soil. By far there is no literature reported MC remediation of petroleum hydrocarbon contaminated soil. MC reactor is exploited to remediate synthetic and actual petroleum hydrocarbon contaminated soil. The effects of reaction reagents and optimal combined parameters are studied. Based on the effects of milling time, rotation speed, ball to mass ratio and reagent to pollutants ratio, the optimal parameters of the MC degradation of petroleum hydrocarbon contaminated soil are obtained. MC degradation process and the final products are analyzed and characterized by means of GC-MS, XRD and FTIR spectrum. According to the data, the reaction kinetics of in MC degradation process are established. The reaction pathway of petroleum hydrocarbon is concluded and the degradation mechanism is also studied. The high-efficiency MC remediation is applied to actual contaminated soil. The dosage of reaction reagents are adjusted according to the soil properties. The research results will not only provide the feasibility of application of soil MC remediation on actual sites remediation, but also supply a new technology and idea to remediate other organic contaminated soil.

机械化学法是一种新型的处理难降解有机固废和污染土壤的技术，目前针对石油烃污染土壤的机械化学修复尚无文献报道。本研究拟采用机械化学反应器，对人工和实际石油烃污染土壤进行修复。研究各种反应试剂对石油烃降解效果的影响，及不同作用的反应试剂的组合使用的最佳条件；通过优化球磨时间、转速、球料比以及物料比等参数，获得石油烃污染土壤机械化学法降解的最佳工艺条件；综合采用气质联用等化学分析方法和X射线衍射、红外光谱等材料表征手段，对降解过程和最终产物进行鉴别和定量，在此基础上建立石油烃的机械化学降解反应动力学，推断反应历程，剖析降解机理。针对实际污染土壤的性质，调整反应试剂的用量，建立高效石油烃污染土壤机械化学修复工艺。研究结果为机械化学土壤修复工艺应用到实际场地修复提供可行性，同时也为其他有机污染土壤修复提供新技术新思路。

随着工业的发展，越来越多的石油烃进入土壤环境，严重威胁着人类的健康。机械化学法运用于含卤有机物的降解已经有较为深入的研究，其具有工艺流程简单、工作条件温和、处理效率高、运行管理方便等诸多优点。本项目利用机械化学法修复石油烃污染土壤，主要研究成果如下：（1）采用机械化学法分别处理实际多环芳烃污染土壤，多环芳烃的降解效果十分良好。污染物的去除率随球磨转速的提高而提高，随球磨时间的延长而增加。在500rpm下球磨6h土壤中蒽去除率达到88.90%，土壤中芘去除率达到93.72%。（2）对比了土壤中MnO2、SiO2、高岭土、Fe2O3、Ca(OH)2、CaO对污染物的降解影响，结果发现MnO2在短时间内对污染物的降解促进作用明显，然而长时间球磨效果不如SiO2和高岭土。（3）苯环结构在球磨的过程中被破坏，随着球磨时间的增加，会生成越来越多的无定形碳。中间产物出现了苯环数更少或饱和度更高的多环芳烃和少量短链烷烃。球磨8h，生成了较多短链烷烃，也出现了C原子数更多的长链烷烃。降解机理为苯环的破坏和最终的碳化。