School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou, 510006, PR China.
School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou, 510006, PR China; Guangdong Provincial Engineering and Technology Research Center for Environmental Risk Prevention and Emergency Disposal, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou, 510006, PR China; Guangdong Engineering and Technology Research Center for Environmental Nanomaterials, Guangzhou, 510006, China; Guangdong Environmental Protection Key Laboratory of Solid Waste Treatment and Recycling, Guangzhou, 510006, PR China.
Chemosphere. 2019 Jun;225:115-125. doi: 10.1016/j.chemosphere.2019.03.009. Epub 2019 Mar 5.
A high removal rate (>99.7%) of combined arsenite (As(III)) and Cd (Cd(II)) in low concentration (1000 μg/L) from contaminated water was achieved by a calcined MgZnFe-CO layered double hydroxide (CMZF) adsorbent. Batch control studies and a series of spectroscopy detection technologies were employed to investigate the removal mechanism and interactions between As(III) and Cd(II) on the interface of water/CMZF. Synergistic adsorption and photooxidation occurred based on the systematical kinetic and isotherm studies. The enhanced removal of As(III) was achieved by the photooxidation, formation of ternary As(III)Cd(II) surface complexes and enhanced hydrogen bond. Meanwhile, oxidative formed negative charged As(V) could reduce the electrostatic repulsion force between Cd(II) cations and play a role as anion bridging, consequently resulted in a stronger attraction between CMZF and Cd(II). Combined with the verdicts of relevant characterizations such as XRD, XPS and EPR, it was assumed that the deep co-removal mechanism could be attributed to the coupling of various processes including intercalation, complexation, photooxidation of As(III) and precipitation of CdCO. Moreover, the successful removal of As(III) and Cd(II) from real water matrix qualified the CMZF a potentially attractive adsorbent for both As(III) and Cd(II) deep treatment in practical engineering.
煅烧镁锌铁-CO 层状双氢氧化物（CMZF）吸附剂实现了对低浓度（1000μg/L）含砷（As(III)）和镉（Cd(II)）废水的高效去除（>99.7%）。采用批控制研究和一系列光谱检测技术，研究了去除机制和水/CMZF 界面上 As(III)和 Cd(II)之间的相互作用。基于系统的动力学和等温线研究，发生了协同吸附和光氧化。光氧化、三元 As(III)Cd(II)表面络合物的形成和氢键的增强促进了 As(III)的去除。同时，氧化形成的带负电荷的 As(V)可以降低 Cd(II)阳离子之间的静电排斥力，并起到阴离子桥的作用，从而导致 CMZF 和 Cd(II)之间更强的吸引力。结合 XRD、XPS 和 EPR 等相关表征的结论，可以认为，这种深度共去除机制可以归因于各种过程的耦合，包括插层、络合、As(III)的光氧化和 CdCO 的沉淀。此外，CMZF 成功地从实际水基质中去除了 As(III)和 Cd(II)，这使其成为实际工程中 As(III)和 Cd(II)深度处理的一种有吸引力的吸附剂。
