Selective adsorption of organic anions in a flow cell with asymmetric redox active electrodes

Electrochemically mediated adsorption is an emerging technology that utilizes redox active (or Faradaic) materials and has exhibited high salt adsorption capacity and superb ion selectivity. Here, we use a redox polymer polyvinylferrocene (PVFc) as the anode and a conducting polymer polypyrrole dope...

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Bibliographic Details
Published in:Water research (Oxford) 2020-09, Vol.182, p.115963-115963, Article 115963
Main Authors: He, Fan, Hemmatifar, Ali, Bazant, Martin Z., Hatton, T. Alan
Format: Article
Language:English
Subjects:
Electrochemical adsorption
Environmental remediation
Micropollutants
Redox active electrodes
Selective adsorption
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Summary:Electrochemically mediated adsorption is an emerging technology that utilizes redox active (or Faradaic) materials and has exhibited high salt adsorption capacity and superb ion selectivity. Here, we use a redox polymer polyvinylferrocene (PVFc) as the anode and a conducting polymer polypyrrole doped with a large anionic surfactant (pPy-DBS) as the cathode for selective electrochemical removal of inorganic and organic components. We fabricated a flow system with alternating adsorption/desorption steps incorporating an electrosorption cell and inline probes (ultraviolet–visible spectroscopy, conductivity and pH sensors) to demonstrate on-the-fly quantification of the ion adsorption performance. The flow system provides a more realistic evaluation of dynamic selectivity for the active materials during cyclic operation than that based on a single equilibrium adsorption step in batch. Our results show a three-fold (cycle) selectivity toward the removal of benzoate, as a representative organic anion, against a 50-fold abundance of perchlorate supporting anion, indicating that electrochemically mediated adsorption is a promising technology for waste water remediation applications. [Display omitted] •Redox-active electrodes for electrochemically-mediated selective adsorption.•Design and fabrication of a flow platform with multiple inline detectors.•Ultra-high salt adsorption rate of 5.6 mg g−1 min−1.•Selective removal of benzoate as a model compound of toxic carboxylate pollutants.•Selectivity of 3 in presence of highly abundant supporting anions (50-fold).
ISSN:0043-1354
1879-2448
DOI:10.1016/j.watres.2020.115963