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Enhanced electrosorption selectivity of phosphate using an anion-exchange resin-coated activated carbon electrode
- Source :
- Journal of Colloid and Interface Science. 600:199-208
- Publication Year :
- 2021
- Publisher :
- Elsevier BV, 2021.
-
Abstract
- Regenerable 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.
- Subjects :
- Capacitive deionization
Inorganic chemistry
chemistry.chemical_element
02 engineering and technology
engineering.material
010402 general chemistry
021001 nanoscience & nanotechnology
01 natural sciences
0104 chemical sciences
Surfaces, Coatings and Films
Electronic, Optical and Magnetic Materials
Biomaterials
Colloid and Surface Chemistry
Membrane
chemistry
Coating
Electrode
medicine
engineering
0210 nano-technology
Ion-exchange resin
Selectivity
Carbon
Activated carbon
medicine.drug
Subjects
Details
- ISSN :
- 00219797
- Volume :
- 600
- Database :
- OpenAIRE
- Journal :
- Journal of Colloid and Interface Science
- Accession number :
- edsair.doi.dedup.....b438ee87a0e876f3e46d53bf33a1ba1b