School of Environmental Science and Engineering, Sun Yat-sen University, Guangdong Provincial Key Lab of Environmental Pollution Control and Remediation, 135 Xingang Xi Road, Guangzhou, 510275, PR China; Laboratoire Réactions et Génie des Procédés, CNRS-Université de Lorraine, 1, rue Grandville, BP20451, 54001, Nancy Cedex, France; South China Institute of Environmental Sciences, Ministry of Environmental Protection, 7 West Street, Yuancun, Guangzhou, 510655, PR China.
School of Environmental Science and Engineering, Sun Yat-sen University, Guangdong Provincial Key Lab of Environmental Pollution Control and Remediation, 135 Xingang Xi Road, Guangzhou, 510275, PR China.
Chemosphere. 2017 Dec;189:479-488. doi: 10.1016/j.chemosphere.2017.09.038. Epub 2017 Sep 13.
Dredging and disposal is commonly used for cleanup of contaminated sediments, leaving the relocated sediments still in need of remediation. In this study, the feasibility of two approaches to using zerovalent iron (ZVI) in conjunction with surfactants to remediate sediments contaminated by polychlorinated biphenyls (PCBs) and Ni was investigated. Approach A is surfactant desorption followed by ZVI treatment and approach B is a simple mixture of ZVI and sediment in surfactant solution. Results of approach A show that 65.24% of PCBs and 2.12% of Ni were desorbed by 1% Envirosurf; however, the sequential ZVI-mediated reductive dechlorination (ZVI-RD) was ineffective due to micelle sequestration by high contents of surfactants while Ni could be almost completely removed. For approach B, less than 1% of coexisting Ni was released to aqueous solution, and 47.18%-76.31% PCBs could be dechlorinated by ZVI with the addition of 0.04% surfactants (Tween-80 and Envirosurf). Results of dechlorination kinetics and ZVI morphologies reveal that surfactants at the concentrations as low as 0.04% were able to enhance the contact of sediment-bound PCBs with ZVI, and also to alleviate ZVI passivation. The PCB mixtures in sediment were continuously desorbed and dechlorinated, yielding lower substituted homologues that are less toxic and less hydrophobic. Thus, a simple mixture of ZVI and contaminated sediments without dewatering appears to be a promising alternative to the remediation of PCBs-contaminated sediments.
疏浚和处置通常用于清理受污染的沉积物，但迁移后的沉积物仍需要修复。本研究探讨了零价铁（ZVI）与表面活性剂联合使用修复多氯联苯（PCBs）和 Ni 污染沉积物的两种方法的可行性。方法 A 是表面活性剂解吸后再用 ZVI 处理，方法 B 是 ZVI 与表面活性剂溶液中的沉积物的简单混合物。方法 A 的结果表明，1%Envirosurf 可解吸 65.24%的 PCBs 和 2.12%的 Ni，但由于表面活性剂含量高导致胶束隔离，顺序 ZVI 介导的还原脱氯（ZVI-RD）无效，而 Ni 几乎可以完全去除。对于方法 B，不到 1%的共存 Ni 释放到水溶液中，添加 0.04%表面活性剂（吐温-80 和 Envirosurf）时，47.18%-76.31%的 PCBs 可被 ZVI 脱氯。脱氯动力学和 ZVI 形态的结果表明，浓度低至 0.04%的表面活性剂能够增强沉积物结合态 PCBs 与 ZVI 的接触，并且减轻 ZVI 的钝化。沉积物中的 PCB 混合物不断解吸和脱氯，生成毒性和疏水性较低的低取代同系物。因此，无需脱水的 ZVI 与受污染沉积物的简单混合物似乎是修复 PCBs 污染沉积物的一种很有前途的替代方法。
