Asymmetric Redox-Polymer Interfaces for Electrochemical Reactive Separations: Synergistic Capture and Conversion of Arsenic
Asymmetric Redox-Polymer Interfaces for Electrochemical Reactive Separations: Synergistic Capture and Conversion of Arsenic
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DOI：
10.1002/adma.201906877
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发表时间：
2019-12-03
影响因子：
29.4
通讯作者：
Su, Xiao
中科院分区：
文献类型：
--
作者：
Kim, Kwiyong;Cotty, Stephen;Su, Xiao
先进的氧化还原聚合物材料为集成电分离和电催化提供了一个强大的平台，特别是在水净化和环境修复应用中。三价砷(As(III))的选择性捕集和修复是净水技术的核心挑战，因为As(III)毒性大，在超稀浓度下很难去除。目前的方法离子选择性低，需要多步过程将砷转化为危害较小的As(V)状态。利用两种氧化还原活性聚合物--聚乙烯基二茂铁(PVF)和聚甲基丙烯酸脂(PTMA)的不对称设计，实现了As(III)到As(V)的串联选择性捕获和转化。在捕获过程中，PVF选择性地吸收As(III)(>；100 mg As/g吸附剂)，在释放过程中，以>；90%的效率协同电催化氧化As(III)为As(V)，PTMA是一种基于自由基氧化还原的聚合物。该系统对实际废水具有90%的去除效率，砷浓度低至10 ppb。通过不对称氧化还原材料的合理设计整合电子转移，与非法拉第碳基材料相比，能效可实现数量级的提高。这项研究首次证明了不对称氧化还原活性聚合物在集成反应分离和电化学中介过程强化环境修复方面的有效性。
Advanced redox-polymer materials offer a powerful platform for integrating electroseparations and electrocatalysis, especially for water purification and environmental remediation applications. The selective capture and remediation of trivalent arsenic (As(III)) is a central challenge for water purification due to its high toxicity and difficulty to remove at ultra-dilute concentrations. Current methods present low ion selectivity, and require multistep processes to transform arsenic to the less harmful As(V) state. The tandem selective capture and conversion of As(III) to As(V) is achieved using an asymmetric design of two redox-active polymers, poly(vinyl)ferrocene (PVF) and poly-TEMPO-methacrylate (PTMA). During capture, PVF selectively removes As(III) with exceptional uptake (>100 mg As/g adsorbent), and during release, synergistic electrocatalytic oxidation of As(III) to As(V) with >90% efficiency can be achieved by PTMA, a radical-based redox polymer. The system demonstrates >90% removal efficiencies with real wastewater and concentrations of arsenic as low as 10 ppb. By integrating electron-transfer through the judicious design of asymmetric redox-materials, an order-of-magnitude energy efficiency increase can be achieved compared to non-faradaic, carbon-based materials. The study demonstrates for the first time the effectiveness of asymmetric redox-active polymers for integrated reactive separations and electrochemically mediated process intensification for environmental remediation.