螯合剂修复重金属污染土壤联合技术研究进展

Effects of Chelating Agent Combination Technologies on Soil Contaminated by Heavy Metals

  • 摘要: 螯合剂作为螯合剂被广泛应用到土壤修复中,但存在修复效率不高及二次污染的问题.为提高螯合剂对土壤重金属污染的修复效率,多种螯合剂联合技术被研究.相比单一螯合剂修复技术,联合修复技术可显著提高重金属污染土壤的修复效率.分析了螯合剂联合修复技术(螯合剂与电动修复技术、螯合剂与植物修复技术、螯合剂与淋洗剂修复技术)及新型联合修复技术(螯合剂与可渗透反应格栅联合技术、螯合剂与超声波联合技术及螯合剂与真菌联合技术),并阐述了各技术的修复原理及影响因素.结果表明,联合修复技术能够有效活化土壤中的重金属,提高修复效率,具有良好的发展前景,但在实际推广应用中仍面临一些挑战:①联合修复过程中影响因素较多,主要包括螯合剂添加方式、土壤酸碱性、复配浓度及淋洗时间等.②联合技术与土壤组分及污染物发生了一系列的物化反应,对重金属的活化与重金属形态之间的机理反应还需进一步明确.③螯合剂的添加可能会增大对植物的毒害效应及重金属向地下渗滤的风险,造成二次污染.④新型联合修复技术目前只应用于实验室内.为使螯合剂充分发挥其最大的实用性,建议未来在以下几方面开展深入研究:进一步开展联合技术的微观机理研究;加大对螯合剂与其他技术的联合修复技术的研究,寻求联合技术的最佳耦合点;研发可生物降解的螯合剂;寻找更加经济有效的方法回收螯合剂.

     

    Abstract: Chelating agents were widely used in soil leaching. However, practical applications revealed that the remediation efficiency was not high and secondary pollution was a problem. To improve the remediation efficiency of chelating agents on soil contaminated by heavy metals, a variety of chelating agent combination technologies have been studied. Compared to a single chelating agent remediation technology, a combined remediation system can significantly improve the remediation efficiency of soils contaminated by heavy metals. Research progresses of combination technologies (chelating agent combined with electric remediation technology, chelating agent combined with phyto remediation technology, and chelating agent combined with eluting agent remediation technology) as well as new combination technologies (chelating agent combined with permeable reactive barrier remediation technology, chelating agent combined with ultrasonic remediation technology, and chelating agent combined with fungus remediation technology) are analyzed, and the mechanisms and influencing factors of remediation technology are elaborated. The results of this study indicate that the combined remediation technologies can effectively mobilize heavy metals in the soil, improve remediation efficiency, and show promise for further development. However, these technologies still face a number of challenges with regard to practical application. First, in the terms of the combined remediation factors, chelating agent addition methods, soil acid, alkalinity, concentration, and leaching time still need to be included. Second, when uniting the technologies with the soil composition and pollutants in a series of physical and chemical reactions, the mobilization of heavy metals, as well as the reaction mechanism between heavy metal forms, further clarification is needed. Third, the addition of chelating agents may increase the deleterious effects on plants and the risk of heavy metal infiltration into the ground, causing secondary pollution. Fourth, new joint repair technology has only been applied in the laboratory. It is recommended to conduct in-depth research on the following aspects:the microcosmic mechanisms of combination technology; analysis of chelating agents and other technologies in order to determine the best coupling points for combination technology; development of biodegradable chelating agents; and search for more economical and effective ways to recover chelating agents.

     

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