电动强化过硫酸钠修复多氯联苯污染土壤的研究

选取PCBs实际污染土壤为研究对象,研究了电动增强Na₂S₂O₈氧化修复PCBs污染土壤的效果,同时考察了两端投加、反转电场和碱活化Na₂S₂O₈对土壤中PCBs降解的影响。结果表明,从阴、阳极分别加入10%的Na₂S₂O₈,增大了电流强度和电渗流量,电场能够促进Na₂S₂O₈在土壤中的迁移以及对土壤中PCBs的降解。从土壤中残留PCBs的分布可以看出,电渗流对氧化剂的迁移作用要高于电迁移。由于阴极的去极化作用,反转电场没有促进Na₂S₂O₈对土壤中PCBs的降解。碱活化Na₂S₂O₈对土壤中PCBs的去除效率最高,达28.7%.PCBs的去除率较低跟土壤的异质性和氧化剂的损失有关。

Electrokinetically Enhanced Persulfate Remediation of PCBs Polluted Soil

Persulfate-based in situ chemical oxidation(ISCO) is a promising technique for remediation of organic compounds contaminated soil and groundwater. However, its application in low permeability soils is limited due to the ineffective delivery of oxidant in such soils. In this study, remediation of PCBs polluted soil by persulfate combined with electrokinetics(EK) was investigated in laboratory-scale experiments. The effects of persulfate additions to both electrodes, electric field reversal and persulfate activation by alkaline on PCBs degradation were also evaluated. Results showed that adding 10% of persulfate to both electrodes increased the current and electroosmotic flow, which thus favored the delivery of persulfate and enhanced the degradation of PCBs in soil. From the distribution of PCBs residues in soil, it showed that electroosmosis was more effective than electromigration for the transportation of persulfate. The electric field reversal did not significantly facilitate the removal of PCBs in soil due to the depolarization occurred in cathode. The activation of persulfate by alkaline yielded the highest PCBs removal efficiency, with 28.7% of PCBs being removed from soils. The soil heterogeneity and persulfate consumption might be responsible for the low removal of PCBs in soils.