Supported by the Young Elite Scientist Sponsorship Program by CAST(YESS) (No. 2018QNRC001)
The serious situation of soil pollution is now threatening the safety of agricultural products, human health and ecological environment, even though, increasing attention has been paid to remediation of soils polluted with organic chemicals in recent decades. The organic chemicals commonly found in the soil include mainly pesticides, petroleum hydrocarbons, antibiotics and so on. As an effective in-situ remediation technology, the technology of electrochemical remediation can be used to remediate organic chemical polluted soils without disturbing their ecological environments. In this paper a review is presented on recent advances in the research on use of electrochemical technologies to remediate polluted soils, including electrokinetic and microbial electrochemical system. Effects of electrode materials, operation conditions and electrode arrangement on pollutant removal efficiency in the process of electrokinetic remediation are analyzed. A conclusion has been reached that both the technologies of electrokinetic and microbial electrochemical remediations can be used to remediate organic chemical-polluted soils, when used in combination with certain facilitating agents, such as surfactants, co-solvents, nanoparticles, and oxidizing chemicals, or with in-situchemical oxidation, bioremediation and phytoremediation, all of which show a synergistic effect on the removal or elimination of organic chemical contaminants in soil. Especially, relationships between variation of the soil microbial communities in the process of soil remediation and removal of pollutants in the process of microbial electrochemical remediation are discussed. Generally speaking, both electrokinetic remediation and microbial electrochemical remediation show good effects of removing organic pollutants from soils, and the former is better than the latter. All the experiments so far carried out show that the adoption of binary metallic oxidation electrodes, nanoparticles modified carbon felt electrode and that optimized electrode arrangement and reactor configuration can improve the pollutant removal efficiency, and the optimization of applied voltage, electrolyte type, operation time, external and internal resistance, electrode area and interval between electrodes can also significantly improve the electrochemical remediation efficacy. Compared with deionized water, Na2SO4, citric acid and NaOH, the NaCl and KH2PO4 are preferable electrolyte during the electrokinetic remediation. Organic pollutants removal efficiency increases with decreasing internal resistance and external resistance. Addition of biochar, carbon fiber, graphene oxide and sand can increase the soil conductivity and mass transport capacity. And microbial electro-remediating cells without external resistance is one of the hot spots in future researches on electrochemical technologies. With the decreased electrode interval, both electricity generation and removal of organic pollutants increase. Microbial community analysis shows that the microorganisms at the anode decrease in diversity and increase in homogeneity in the process of the microbial electrochemical system removing organic pollutants from soil. The exoelectrogens play an important role in the anode cell, while degrading bacteria are effective in the soil near the cathode and anode. In addition, the coupling of electrochemical remediation with chemical oxidation, phytoremediation and bioremediation may make it possible to extrapolate the technology of electrochemistry on a large scale. In order to realize the practical application of the technology to remediation of organic-chemical polluted soils, it is necessary to improve the electrochemical remediation technology by optimizing configuration of the reactor, soil conductivity and electrode materials in the future. Moreover, it is anticipated that mechanisms of the electrochemical remediation technology and characteristics of the functional microbial community relative to type of organic pollutants will be one of the hot spots in the research on microbial electrochemical remediation.
杨珍珍,耿兵,田云龙,李红娜.土壤有机污染物电化学修复技术研究进展[J].土壤学报,2021,58(5):1110-1122. DOI:10.11766/trxb202004280200 YANG Zhenzhen, GENG Bing, TIAN Yunlong, LI Hongna. Research Progresses on Remediation of Organic Contaminated Soils with Electrochemical Technologies[J]. Acta Pedologica Sinica,2021,58(5):1110-1122.复制