Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao 266100, China; College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China.
Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao 266100, China; Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering (MEGE), Qingdao 266100, China; College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China.
Sci Total Environ. 2021 Aug 20;783:146999. doi: 10.1016/j.scitotenv.2021.146999. Epub 2021 Apr 9.
Carbon tetrachloride (CT) is highly toxic and recalcitrant in groundwater. In recent years, zero-valent aluminum (ZVAl) is highly reductive but limited by its surface passivation film. One of the effective ways to overcome this bottleneck is to add ligands. In this paper, compared with several other ligands, sodium citrate (SC), a natural organic ligand, was introduced to enhance microscale ZVAl (mZVAl) reactivity for the reductive degradation of CT. The results showed that the SC system could effectively reduce but not completely dechlorinate CT and electron utilization efficiency was as high as 94%. However, without ligands, mZVAl is chemically inert for CT degradation. Through SEM-EDS, BET, XRD, and XPS characterizations and H evolution experiments, enhanced mZVAl surface corrosion at the solid-liquid interface of mZVAl/SC system was verified. SC participated in the complexation corrosion reaction with surface inert film to form Al[Cit] complex, which made internal Al active sites exposed and then promoted mZVAl corrosion. In the five consecutive reuse experiments of mZVAl, CT can be completely degraded, which indicates that mZVAl, with the help of SC, has excellent sustainable utilization efficiency.
四氯化碳（CT）在地下水中有很强的毒性和抗降解性。近年来，零价铝（ZVAl）具有很强的还原性，但受到其表面钝化膜的限制。克服这一瓶颈的有效方法之一是添加配体。在本文中，与其他几种配体相比，天然有机配体柠檬酸钠（SC）被引入以增强微尺度 ZVAl（mZVAl）的反应活性，用于 CT 的还原降解。结果表明，SC 体系可以有效地还原但不能完全脱氯，电子利用率高达 94%。然而，在没有配体的情况下，mZVAl 对 CT 降解是化学惰性的。通过 SEM-EDS、BET、XRD 和 XPS 特性和 H 演化实验，验证了 mZVAl/SC 体系固液界面上增强的 mZVAl 表面腐蚀。SC 与表面惰性膜参与络合腐蚀反应，形成 Al[Cit]配合物，使内部 Al 活性位暴露，从而促进 mZVAl 腐蚀。在 mZVAl 的五次连续重复使用实验中，CT 可以完全降解，这表明在 SC 的帮助下，mZVAl 具有优异的可持续利用效率。
