State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, No. 19 Xinjiekouwai Street, Beijing, 100875, China.
Hangzhou Yanqu Information Technology Co., Ltd., No. 712 Wen'er West Road, Xihu District, Hangzhou, 310003, China.
Environ Pollut. 2022 Jun 15;303:119160. doi: 10.1016/j.envpol.2022.119160. Epub 2022 Mar 15.
Currently, alleviating antimony (Sb) contamination in aqueous solutions is crucial for restoring and recovering ecological and environmental health. Due to its toxicity, bioaccumulation and mobile characteristics, developing an efficient technique for antimony decontamination is imperative. Herein, we prepared a Fe-Cu-chitosan (FCC) composite by a one-step coprecipitation method, in which nanoscale Fe/Cu acts as the active sites and the whole structure is exhibited as porous microscale particles. A Fe/Cu proportion of 2/1 (FCC-2/1) was determined to be the optimum proportion for antimony adsorption, specifically 34.5 mg g for Sb(III) and 26.8 mg g for Sb(V) (initial concentration: 5.0 mg L). Spectral characterization, batch experiments and density functional theory (DFT) simulations were applied to determine the adsorption mechanism, in which surface hydroxyls (-OH) were responsible for antimony complexion and Fe-Cu coupling was a major contributor to adsorption enhancement. According to kinetic analysis, Cu provided an electrostatic attraction during the adsorption process, which facilitated the transportation of antimony molecules to the material interface. In the meantime, the FCC electronic structure was modified due to the optimization of the Fe-Cu interface coupling. Based on the Mullikan net charge, the intrinsic Fe-O-Cu bond might favor interfacial electronic redistribution. When the antimony molecule contacted the adsorption interface, the electrons transferred swiftly as Fe/Cu 3d and O 2p orbital hybridization occurred, thus inducing a stabilizing effect. This work may offer a new perspective for binary oxide construction and its adsorption mechanism analysis.
目前，缓解水体中的锑（Sb）污染对于恢复和保护生态环境健康至关重要。由于锑的毒性、生物累积性和迁移性，开发高效的锑去除技术势在必行。本研究采用一步共沉淀法制备了一种 Fe-Cu-壳聚糖（FCC）复合材料，其中纳米级的 Fe/Cu 作为活性位点，整个结构呈现为多孔微尺度颗粒。确定 Fe/Cu 比例为 2/1（FCC-2/1）时对 Sb(III)和 Sb(V)的吸附效果最佳，吸附量分别为 34.5 和 26.8 mg g（初始浓度：5.0 mg L）。光谱表征、批量实验和密度泛函理论（DFT）模拟确定了吸附机制，其中表面羟基（-OH）负责 Sb 的络合，而 Fe-Cu 偶联是吸附增强的主要原因。根据动力学分析，Cu 在吸附过程中提供了静电吸引，促进了 Sb 分子向材料界面的传输。同时，由于 Fe-Cu 界面耦合的优化，FCC 的电子结构发生了改变。根据 Mullikan 净电荷，内在的 Fe-O-Cu 键可能有利于界面电子重新分布。当 Sb 分子接触吸附界面时，由于 Fe/Cu 3d 和 O 2p 轨道杂化发生，电子迅速转移，从而产生稳定作用。这项工作为二元氧化物的构建及其吸附机制分析提供了新的视角。
