TY - JOUR
T1 - Asymmetric Redox‐Polymer Interfaces for Electrochemical Reactive Separations
T2 - Synergistic Capture and Conversion of Arsenic
AU - Kim, Kwiyong
AU - Cotty, Stephen
AU - Elbert, Johannes
AU - Chen, Raylin
AU - Hou, Chia‐hung
AU - Su, Xiao
N1 - Funding Information:
K.K. and S.C. contributed equally to this work. The authors acknowledge the support of the University of Illinois, Urbana-Champaign for startup funding, and the support of the National Science Foundation under Grant #1931941. SEM and XPS were carried out in the Frederick Seitz Materials Research Laboratory Central Research Facilities, University of Illinois. Major funding for the Bruker EMXPlus was provided by National Science Foundation Award 1726244 (2017) to the School of Chemical Sciences EPR lab at the University of Illinois, Urbana-Champaign. The authors thank Loi Chen and Kristina Roth for their aid in the experiments with the flow-by electrochemical cell, and Dr. Toby Woods for assistance with the EPR measurements. The authors also thank Haley Vapnik for her help with the GPC measurements.
PY - 2020/2/13
Y1 - 2020/2/13
N2 - 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.
AB - 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.
KW - arsenic
KW - electrochemical separation
KW - reactive conversion
KW - redox-active polymers
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U2 - 10.1002/adma.201906877
DO - 10.1002/adma.201906877
M3 - Article
C2 - 31793695
SN - 0935-9648
VL - 32
JO - Advanced Materials
JF - Advanced Materials
IS - 6
M1 - 1906877
ER -