Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, 2999 North Renmin Road, Shanghai 201620, China; Shanghai Institute of Pollution Control and Ecological Security, 1239 Siping Road, Shanghai 200092, China.
Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, 2999 North Renmin Road, Shanghai 201620, China.
J Hazard Mater. 2021 Apr 5;407:124384. doi: 10.1016/j.jhazmat.2020.124384. Epub 2020 Nov 14.
Advanced nanotechnologies for efficient arsenic decontamination remain largely underdeveloped. The most abundant inorganic arsenic species are neutrally-charged arsenate, As(III), and negatively-charged arsenite, As(V). Compared with As(V), As(III) is 60 times more toxic and more difficult to remove due to high mobility. Herein, an electrochemical filtration system was rationally designed for one-step As(III) decontamination. The key to this technology is a functional electroactive carbon nanotube (CNT) filter functionalized with sea urchin-like FeOOH. With the assistance of electric field, CNT-FeOOH anodic filter can in situ transform As(III) to less toxic As(V) while passing through. Then, as-produced As(V) could be effectively sequestrated by FeOOH. The sufficient exposed sorption sites, flow-through design, and filter's electrochemical reactivity synergistically guaranteed a rapid arsenic removal kinetic. The underlying working mechanism was unveiled based on systematic experimental investigations and theoretical calculations. The system efficacy can be adapted across a wide pH range and environmental matrixes. Exhausted CNT-FeOOH filters could be effectively regenerated by chemical washing with diluted NaOH solution. Outcomes of the present study are dedicated to provide a straightforward and effective strategy by integrating electrochemistry, nanotechnology, and membrane separation for the removal of arsenic and other similar heavy metals from water bodies.
高效除砷的先进纳米技术仍在很大程度上尚未开发。最丰富的无机砷物种为中性的砷酸盐（As(V)）、亚砷酸盐（As(III)）。与 As(V)相比，As(III)的毒性高 60 倍，由于其高迁移性，更难去除。在此，本文合理设计了一种电化学过滤系统，用于一步去除 As(III)。该技术的关键是一种功能化的具有海胆状 FeOOH 的功能性电化学活性碳纳米管（CNT）过滤器。在电场的辅助下，CNT-FeOOH 阳极过滤器可以原位将 As(III)转化为毒性较低的 As(V)，同时通过。然后，产生的 As(V)可以被 FeOOH 有效固定。充足的暴露吸附位点、流通式设计和过滤器的电化学反应性协同保证了快速的砷去除动力学。基于系统的实验研究和理论计算，揭示了其潜在的工作机制。该系统的功效可以适应广泛的 pH 值范围和环境基质。用过的 CNT-FeOOH 过滤器可以通过用稀 NaOH 溶液进行化学清洗来有效再生。本研究的结果旨在提供一种将电化学、纳米技术和膜分离集成用于从水体中去除砷和其他类似重金属的简单而有效的策略。
