零价铁基可渗透反应墙技术治理Cr(Ⅵ)污染地下水的研究进展

Zero-valent iron-based permeable reactive barrier technology research progress on remediation of Cr(Ⅵ)-contaminated groundwater

可渗透反应墙(Permeable Reactive Barrier,PRB)技术原位处理污染地下水是地下水治理领域的重要研究方向之一,以零价铁为填料的PRB在去除Cr(Ⅵ)污染地下水时具有显著优势。归纳总结了零价铁基PRB治理Cr(Ⅵ)污染地下水的反应机理,包括还原(主要作用)、吸附、共沉淀、微生物作用和铁腐蚀,并指出目前存在的反应性差和沉淀堵塞问题。硫化改性、双金属改性、负载碳材料和材料复配增强了零价铁对Cr(Ⅵ)的反应性能。耦合微生物菌(Cr(Ⅵ)还原菌、铁还原菌和硫酸盐还原菌等)治理方法由于更加绿色而受到越来越多的关注,但需注意微生物生长堵塞问题。电动治理技术强化了PRB被动捕获污染羽的能力并增强了PRB寿命。介绍了零价铁基PRB的渗透性能,并考虑水文地质条件、副反应以及二次污染等问题,以对未来研究做出展望,为零价铁基PRB技术治理Cr(Ⅵ)污染地下水的研究与应用提供参考。

In this paper,from the perspective of reaction mechanism and strengthening method,the research progress of zero-valent iron-based permeable reactive barrier technology(ZVI PRB)in situ treatment of Cr(Ⅵ)contaminated groundwater was reviewed,and the influence of ZVI PRB on permeability was concerned.This paper introduced the reaction mechanism of ZVI PRB for the remediation of Cr(Ⅵ)contaminated groundwater,including reduction(playing a main role),adsorption,coprecipitation,microbial action and iron corrosion.The performance of the ZVI PRB is generally satisfactory,but there are problems such as poor reactivity,easy passivation,and sedimentation clogging.This paper summarized various strengthening methods:(1)vulcanization modification,bimetallic modification,carbon loaded material and material combination enhance the reactivity of ZVI to Cr(Ⅵ);(2)Coupling microbial bacteria[Cr(Ⅵ)reducing bacteria,ironreducing bacteria,and sulfate-reducing bacteria,etc.]enhance the reactivity and service life of ZVI PRB,and more and more people paid attention to the green of this method,but attention should be paid to the problem of microbial growth blockage;(3)Electrokinetic remediation technology strengthens the passive capture capability of PRB and prolongs the life of PRB.This paper focuses on the permeability of ZVI PRB.A high or low permeability coefficient is not conducive to the effective operation of PRB.The permeability coefficient of ZVI PRB can be designed several times as the permeability coefficient of the aquifer.According to the current research progress,the following two recommendations are put forward:(1)to continuously explore how to increase the reactivity of ZVI and its advanced use methods,to achieve efficient removal and high costeffectiveness;(2)to study and evaluate the expected effective life of PRB,especially to deepen the understanding of the principle of PRB and the change of its permeability coefficient from the level of pilot demonstration and site practical application.