Shen Y.-YHsu C.-CTsai S.-WHou C.-H.CHIA-HUNG HOU2021-08-052021-08-052021219797https://www.scopus.com/inward/record.uri?eid=2-s2.0-85106276434&doi=10.1016%2fj.jcis.2021.04.129&partnerID=40&md5=6199b50588cf8b9771cf5ce435f513a0https://scholars.lib.ntu.edu.tw/handle/123456789/576987Regenerable methods for phosphate (P) recycling have received intense attention due to their potential environmental and economic benefits. In this study, to improve the electrosorptive removal of P in membrane capacitive deionization, an activated carbon (AC) electrode was coated with a heterogeneous anion-exchange resin layer, and named the AE-AC composite electrode. It was shown that the AE-AC electrode exhibited a good capacitive behavior for electrical double-layer charging. The batch-mode experiments indicted that when the solution pH changed from 5 to 8, the predominant P species shifted from monovalent H2PO4? to divalent HPO42? that was preferentially electroadsorbed for competitive electrosorption with Cl?. Importantly, the AE-AC composite electrode significantly increased the selectivity coefficient of P over Cl? to 0.56 that was 2.24-fold greater than that of the uncoated AC electrode, at 1.2 V in single-pass mode operation. This improvement can be ascribed to the preferential transport of P through the thin coating layer containing quaternary amine functional groups. The permselectivity of the coating also significantly increased the electrosorption capacity of P from 0.031 to 0.101 mmol/g with a high charge efficiency (97%) by the reduction in the co-ion repulsion effect. When the reverse voltage (?1.2 V) was applied, electroadsorbed P was reversibly desorbed from the AE-AC electrode in repeated operation. This work suggests that coating an anion-exchange resin layer on the surface of a carbon electrode shows great potential to improve the selective removal of P through electrosorption. ? 2021 Elsevier Inc.Activated carbon; Coatings; Ion exchange resins; Ions; Activated carbon electrode; Anion exchange resins; Capacitive behavior; Composite electrode; Electrical double layers; Membrane capacitive deionization; Regenerable methods; Selectivity coefficient; Electrodes[SDGs]SDG11journal article10.1016/j.jcis.2021.04.1292-s2.0-85106276434