Removal of Cu and Pb in Contaminated Loess by Electrokinetic Remediation Using Novel Hydrogel Electrodes Coupled with Focusing Position Adjustment and Exchange Electrode

IF 3.4 4区工程技术 Q2 ENGINEERING, CHEMICAL

Processes Pub Date : 2025-09-12 DOI:10.3390/pr13092915

C. L. Liu, Wenle Hu, Xiang Zhu, Shixu Zhang, W.G. Wang

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Abstract

Electrokinetic (EK) remediation is a promising approach for the removal of heavy metals from fine-grained soils; however, its efficiency is often hindered by electrode polarization, pH imbalance, and ion accumulation. In this study, we developed a novel hydrogel-based electrode (NH electrode), composed of sodium alginate and multilayer graphene oxide (GO), to enhance the electrokinetic removal of Cu2+ and Pb2+ from loess. The electrode was systematically characterized by atomic force microscopy (AFM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS), confirming its structural integrity, electrochemical activity, and interfacial conductivity. The NH electrode exhibited a smooth layered graphene structure with abundant oxygen-containing functional groups (AFM), negligible electrochemical polarization (CV), and low internal resistance with high conductivity (EIS), enabling efficient ion transport and adsorption. Electrokinetic tests revealed that the NH electrode outperformed conventional graphene (Gr) and electrokinetic graphite (EKG) electrodes. Single regulation strategies, including focusing position adjustment and electrode exchange, improved local removal efficiency by mitigating ion accumulation in targeted regions. The combined regulation strategy, integrating both measures, achieved the most uniform Cu2+ and Pb2+ removal, significantly suppressing hydroxide precipitation in cathodic zones and enhancing ion migration in the mid-section. Compared with literature-reported systems under similar or even more favorable conditions, the NH electrode and combined regulation approach achieved superior performance, with Cu2+ and Pb2+ removal efficiencies reaching 47.25% and 16.93%, respectively. These findings demonstrate that coupling electrode material innovation with spatial–temporal pH/flow field regulation can overcome key bottlenecks in EK remediation of heavy-metal-contaminated loess.

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新型水凝胶电极耦合聚焦位置调节和交换电极的电动修复去除污染黄土中的铜和铅

电动力学（EK）修复是去除细粒土壤中重金属的一种有前途的方法。然而，其效率往往受到电极极化、pH不平衡和离子积累的阻碍。在这项研究中，我们开发了一种新型的水凝胶电极（NH电极），由海藻酸钠和多层氧化石墨烯（GO）组成，以增强黄土中Cu2+和Pb2+的电动去除。采用原子力显微镜（AFM）、循环伏安法（CV）和电化学阻抗谱（EIS）对电极进行了系统表征，证实了其结构完整性、电化学活性和界面电导率。NH电极具有光滑的层状石墨烯结构，具有丰富的含氧官能团（AFM），可以忽略电化学极化（CV），具有低内阻和高电导率（EIS），能够实现高效的离子传输和吸附。电动测试表明，NH电极优于传统的石墨烯（Gr）和电动石墨（EKG）电极。单一调节策略，包括聚焦位置调整和电极交换，通过减少目标区域的离子积累来提高局部去除效率。结合这两种措施的组合调控策略，实现了最均匀的Cu2+和Pb2+去除，显著抑制了阴极区氢氧化物沉淀，增强了中段离子迁移。与文献报道的系统相比，在相似甚至更有利的条件下，NH电极和组合调节方法取得了更好的性能，Cu2+和Pb2+的去除效率分别达到47.25%和16.93%。研究结果表明，电极材料创新与时空pH/流场调节耦合可以克服重金属污染黄土EK修复的关键瓶颈。

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来源期刊

Processes Chemical Engineering-Bioengineering

CiteScore

5.10

自引率

11.40%

发文量

2239

审稿时长

14.11 days

期刊介绍： Processes (ISSN 2227-9717) provides an advanced forum for process related research in chemistry, biology and allied engineering fields. The journal publishes regular research papers, communications, letters, short notes and reviews. Our aim is to encourage researchers to publish their experimental, theoretical and computational results in as much detail as necessary. There is no restriction on paper length or number of figures and tables.