Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
Environ Technol. 2013 Mar-Apr;34(5-8):637-44. doi: 10.1080/09593330.2012.710405.
The removal of polychlorinated biphenyls (PCBs) from soil contaminated with capacitor oil, using microwave (MW)-irradiated manganese dioxide (MnO2), was examined under different conditions. The effects of different types of MnO2 added as oxidant, as well as the initial amount of water, MnO2, and sulphuric acid solution, were also investigated. The removal efficiencies for dichlorobiphenyls, trichlorobiphenyls, tetrachlorobiphenyls, pentachlorobiphenyls, hexachloro-biphenyls, heptachlorobiphenyls, and octachlorobiphenyls were approximately 95.9%, 82.5%, 52.0%, 71.6%, 62.5%, 28.6%, and 16.1%, respectively, by 800 W MW irradiation for 45 min with the assistance of 0.1 g delta-MnO2 and 0.2 mL water in 1.0 g severely PCB-contaminated soil (sigma PCB = 1560.82 mg/kg); meanwhile, the concentrations of Mn2+ ions detected were from 10.6 +/- 1.9 mg/kg at 0 min to 108.2 +/- 7.8 mg/kg after 45 min MW irradiation, indicating that MnO2 acted as not only a MW absorber but also an oxidizer. Removal efficiencies of PCBs from contaminated soil increased with increasing the amounts of water and MnO2 added. The type of MnO2 also affected the removal of PCBs, following an order of delta-MnO2 > alpha-MnO2 > beta-MnO2. The addition of low concentration of sulphuric acid (such as 1.0 mol/L) solution was favourable for the removal of low chloro-substituted PCBs, but the addition of more than 1.0 mol/L sulphuric acid reduced the removal of all PCBs. The pronounced removal of PCBs from contaminated soil in a short treatment time indicates that MW irradiation with the assistance of MnO2 is an efficient and promising technology for the remediation of PCB-contaminated soil.
使用微波（MW）辐照二氧化锰（MnO2）从电容器油污染的土壤中去除多氯联苯（PCBs），在不同条件下进行了研究。还研究了添加不同类型的 MnO2 作为氧化剂以及初始水量、MnO2 和硫酸溶液的影响。用 800 W MW 照射 45 分钟，在 1.0 g 严重 PCB 污染土壤（sigma PCB = 1560.82 mg/kg）中加入 0.1 g delta-MnO2 和 0.2 mL 水，二氯联苯、三氯联苯、四氯联苯、五氯联苯、六氯联苯、七氯联苯和八氯联苯的去除效率分别约为 95.9%、82.5%、52.0%、71.6%、62.5%、28.6%和 16.1%；同时，在 45 分钟 MW 照射后，检测到的 Mn2+离子浓度从 0 分钟的 10.6 +/- 1.9 mg/kg 增加到 108.2 +/- 7.8 mg/kg，表明 MnO2 不仅作为 MW 吸收剂，而且作为氧化剂。添加的水量和 MnO2 量增加，污染土壤中 PCBs 的去除效率也随之提高。MnO2 的类型也影响 PCBs 的去除，其顺序为 delta-MnO2 > alpha-MnO2 > beta-MnO2。添加低浓度的硫酸（如 1.0 mol/L）溶液有利于去除低氯取代的 PCBs，但添加超过 1.0 mol/L 的硫酸会降低所有 PCBs 的去除效率。在短时间内从污染土壤中去除 PCBs 的效果显著，表明在 MnO2 的辅助下进行 MW 辐照是一种有效且有前景的 PCB 污染土壤修复技术。
