微米铁复合生物碳源对地下水中1, 2-二氯乙烷的高效去除

来自 : www.hjkx.ac.cn/hjkx/ch/html/20 发布时间：2021-03-24

Abstract: In order to explore the degradation mechanism of 1, 2-dichloroethane (1, 2-DCA), which is one of the refractory saturated chlorinated hydrocarbons, the groundwater and aquifer soil from a chlorinated hydrocarbon contaminated site in Beijing were collected to carry out microcosm experiments under anaerobic conditions using zero-valent iron (ZVI) coupled with biological action. The removal rate of 1, 2-DCA under different conditions was investigated by adding a composite agent consisting of micron zero-valent iron (mZVI), a biological carbon source, and a few nutrients. Changes of the groundwater physical and chemical parameters were monitored. The results showed that, when the dosage of the composite agent reached 3%, the concentration of 1, 2-dichloroethane could be reduced to below the detection limit within 15 days. Neutral pH and the presence of SO42- were more conducive to the dechlorination of 1, 2-DCA. After 30 days, an obvious increase in the ethene concentration was detected (0.17-0.52 mg·L-1) and no significant vinyl chloride, chloroethane, or ethane was observed in the microcosms, illustrating that the dihaloelimination was the main degradation pathway of 1, 2-DCA in the system. In addition, the groundwater could maintain a low oxidation-reduction potential (-100 to -300 mV), dissolved oxygen ( 0.5 mg·L-1), and a suitable pH value (6.5-7.5) for a long time under the synergy of mZVI and a biological carbon source. This was beneficial to the activity of anaerobic microorganisms and to the dechlorination reaction.