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Redox‐active electrosorbents are promising platforms for selective separations. However, these platforms face intrinsic challenges in extracting multiple species simultaneously, as their binding mechanisms are typically tailored to separate a single ion preferentially. Here, bipolar electrochemistry is leveraged to introduce a new strategy for the multiplexed use of redox‐active and capacitive materials for separations. Using polyvinyl ferrocene (PVF)‐, Prussian blue analog (PBA)‐functionalized, and carbon‐based electrodes, multicomponent separations within a modular bipolar electrode (BPE) platform are demonstrated. The multiplexed BPE system provides distinct electrochemical environments within each BPE pair, enabling parallel selective separations. With three identical PVF BPEs, arsenic uptake increased linearly from 41.4 to 115.4 mgAsgPVF−1, highlighting the scalability of the system. Moreover, deploying three distinct BPE pairs—PBA, PVF, and carbon—enables simultaneous potassium recovery (11.0 mg g−1), arsenic removal (19.8 mg g−1), and desalination (4.2 mg g−1) from secondary wastewater, demonstrating real‐world applicability. This wireless, membraneless architecture enables process‐intensified selective separations by precisely controlling local electric fields on individual redox‐active materials, facilitating electrosorption and regeneration across diverse BPE systems within a unified process.
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Asymmetric Redox‐Polymer Interfaces for Electrochemical Reactive Separations: Synergistic Capture and Conversion of Arsenic
Abstract 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.
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- Award ID(s):
- 1931941
- PAR ID:
- 10458789
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials
- Volume:
- 32
- Issue:
- 6
- ISSN:
- 0935-9648
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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