High-Performance Carbon Electrodes Modified with Polyaniline for Stable and Selective Anion Separation
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2022-06-01
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Abstract
Capacitive deionization (CDI) is a technology used for water desalination and ion recovery based on the use of capacitive electrodes. Typically, the porous carbon electrodes used for CDI display limited ion storage capacity and selectivity due to the mechanism of ion storage in the electric double layer, but impressive improvements have been achieved using alternative, redox-based electrode materials, including conducting polymers like polyaniline (PAni). PAni is capable of capturing anions based on redox chemistry, but it degrades at anodic potentials typically used in CDI. In this work, we employed a multi-channel membrane CDI cell to map the stability window of a porous carbon electrode modified with PAni by controlling the anodic potential. We demonstrated for the first time that applying a potential as low as + 0.35 V (vs. Ag/AgCl) yields a stable and high chloride removal capacity (65 mgCl/gAnode) with charge and coulombic efficiencies close to 100% for CDI. Furthermore, this is first work to explore the selectivity of the PAni-modified CDI electrodes towards chloride in binary solutions, evidencing that chloride is preferred regardless the valence of the competing anions. We believe that this work provides an important contribution for a larger figure, one in which CDI can be used for both high-performance water desalination, and efficient anion-selective removal and recovery.
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Publisher Copyright: © 2022 The Authors
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Capacitive Deionization , Ion Selectivity , Polyaniline , Conducting Polymer , Electrode Stability , Capacitive Deionization , Ion Selectivity , Polyaniline , Conducting Polymer , Electrode Stability , Analytical Chemistry , Filtration and Separation , SDG 6 - Clean Water and Sanitation , Project ID , info:eu-repo/grantAgreement/EC/H2020/682444/EU/Electro-motion for the sustainable recovery of high-value nutrients from waste water/E-motion , info:eu-repo/grantAgreement/EC/H2020/682444/EU/Electro-motion for the sustainable recovery of high-value nutrients from waste water/E-motion , Funding Info , This work was supported by the European Research Council (ERC Consolidator Grant 682444, E-motion, PI L.d.S)". L.A.M.R. thanks the Sao Paulo State Research Foundation (FAPESP, grant 2017/19838-5)._x000D_ The authors thank KaÃque S. G. C. Oliveira for the synthesis of the PAC material, Dr Sidharam Pujari for the AES measurements, and Ellen Dautzenberg for the nitrogen adsorption/desorption measurements. The authors also would like to thank the participants of the Advanced Materials for Chemical Selectivity group of the Laboratory of Organic Chemistry (WUR), particularly the CDI team, for the fruitful discussions. , This work was supported by the European Research Council (ERC Consolidator Grant 682444, E-motion, PI L.d.S)". L.A.M.R. thanks the Sao Paulo State Research Foundation (FAPESP, grant 2017/19838-5)._x000D_ The authors thank KaÃque S. G. C. Oliveira for the synthesis of the PAC material, Dr Sidharam Pujari for the AES measurements, and Ellen Dautzenberg for the nitrogen adsorption/desorption measurements. The authors also would like to thank the participants of the Advanced Materials for Chemical Selectivity group of the Laboratory of Organic Chemistry (WUR), particularly the CDI team, for the fruitful discussions.
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Zornitta , R L , Ruotolo , L A M & de Smet , L C P M 2022 , ' High-Performance Carbon Electrodes Modified with Polyaniline for Stable and Selective Anion Separation ' , Separation and Purification Technology , vol. 290 , 120807 , pp. 120807 . https://doi.org/10.1016/j.seppur.2022.120807