铁锰负载碳纤维/中空纤维膜复合人工根系强化植物萃取修复土壤/地下水中砷污染

The treatment of heavy metal pollution is a major problem related to the safety of agricultural food and drinking water, currently the hyperaccumulative plant for arsenic remediation is the hot research spot technology. However, the hyperconcentration plants are limited to the depth of the root, so it's hard to combine the remediation of the soil and groundwater, and the incompatibility between the root scale and the groundwater level limits its deep application. This project was established by applying the capillary root - Fe/Mn oxides on carbon fiber and biodegradable and recyclable hollow fiber membrane is composed of artificial root root, the electrochemical and physicochemical adsorption and biochemical extraction effect by combining the construction of electrochemical enhanced adsorption desorption / capillary effect and new artificial root migration enhanced plant uptake transport coordination system, coupling hyperaccumulate plant rhizosphere enhanced arsenic adsorption in groundwater and soil with artificial root; expand the root hyperaccumulator absorption range, coupling to realize the growth of plant roots and Fe/Mn loaded carbon fiber adsorption-hollow fiber membrane capillary migration artificial roots, electrochemical studies of electrostatic field controlled enhanced rhizosphere arsenic mass transfer, to achieve from the "soil and groundwater - artificial root - plants" multi medium under the environment carbon fiber adsorption - Electrochemical desorption electrostatic field migration and capillary transport in groundwater - Pteris vittata absorption combine migration and transformation model. The study of adsorption migration and transformation mechanism of arsenic in compound remediation model is of great significance to the development of combined remediation technology of soil and groundwater pollution.

土壤和地下水重金属污染是关系农产品和饮用水安全的重大问题，植物修复砷污染修复技术研究热点。但超富集植物受限于植株个体无法涉及到深层土壤及地下水，根系尺度小与污染不匹配限制了其应用。本项目制备以铁锰负载碳纤维和可降解/回收中空纤维膜结合组成的毛细/主根人工根系，将电化学-物化吸附作用与生物萃取作用相结合，构建电化学强化吸附解吸与电迁移协同毛细上升作用输移砷的新型人工根系体系，利用电化学刺激超富集植物根系与人工根系的协同结合，从而强化对土壤和地下水中砷的富集萃取，扩大超富集植物的原位根系吸收范围，实现植物根系与铁锰负载碳纤维-中空纤维膜人工根系的交联耦合，研究电化学静电场可控强化根际砷传质的方式，实现环境中砷从“土壤地下水-人工根系-植物体内”多介质环境下的“碳纤维负载铁锰吸附-电化学脱附-静电场迁移-中空毛细运输-蜈蚣草富集”协同迁移转化模式，研究砷在复合修复模式下的吸附-迁移-转化机制，项目对扩展土壤与地下水污染联合修复技术应用研究具有重要意义

本项目对纳米铁锰的制备及导电材料负载研究，基于活性炭，碳纤维，中空纤维膜负载的导电电极材料，研究了超声强化负载方式，有机支撑体强化负载量，其中超声强化提高负载量32%，研究了碳纤维和活性炭的导电电极材料强化对砷/铬阴离子重金属的土壤和地下水吸收体系，pH>9抑制对砷的吸附，空白对照纳米铁锰负载材料通过电吸附提高吸附容量13.5%,纳米铁锰的饱和吸附容量达到105mg/g（15℃），铁锰负载活性炭的吸附容量为1.9mg/g，与电化学调控的相关关系，研究了中空纤维膜的微观剖面结构与微观表面构造对纳米铁锰材料负载效果的影响，由于碳纤维与中空纤维膜的耦合委托加工生产难度较大，分别研究了纳米铁锰负载碳纤维电化学调控和纳米铁锰负载中空纤维膜强化对地下水中砷的吸附去除，初步构建了电化学强化吸附/反向电解的耦合作用强化对土壤和地下水中砷的吸附富集，电吸附时调控电压1.2-3.5V之间，反向电解时电压为5V-8V，提高了根系的碱性便于砷的洗脱，并利用人工根系的负载和提取作用，将砷吸附/脱附液通过碳纤维/中空纤维膜的毛细上升作用与电迁移协同输移。人工根系扩大超富集植物的原位根系吸收范围，由于疫情原因等错过了对超富集植物的野外调研采样，还没有实现对植物根系生长与铁锰负载碳纤维人工根系的交联耦合的深入研究。但单纯利用人工根系实现了电化学静电场与水力可控强化人工根系砷传质的方式。同时对铬污染土壤进行中空纤维膜人工根系耦合电化学淋洗研究，可以提高淋洗效率，降低直接注入药剂导致地下水的二次污染，等利用生物吸附材料与厌氧微生物耦合形成微生物燃料电池对强化铬的吸附和迁移转化，人工根系基于陶瓷膜中空纤维膜等基体耦合碳纤维电化学调控，可以对微生物原位修复，纳米材料的利用，防止土壤地下水修复药剂的二次污染，项目成果对于扩展土壤与地下水环境中植物原位修复技术的发展具有重要意义。