Efficient recovery of nitrate from municipal wastewater via MCDI using anion-exchange polymer coated electrode embedded with nitrate selective resin

David Inhyuk Kim, Ralph Rolly Gonzales, Pema Dorji, Gimun Gwak, Sherub Phuntsho, Seungkwan Hong, Hokyong Shon

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

A NO3—selective carbon electrode coated with an anion-selective polymer with polystyrenic macroporous nitrate—selective A520E resin particles (in chloride form; particle size: 300–1200 μm) was fabricated for desalination of municipal wastewater and NO3 recovery during membrane capacitive deionization (MCI). Several issues, such as electrosorption/regeneration efficiency, selectivity of NO3, and removal from real wastewater, were addressed to demonstrate the suitability of coated electrodes. The NO3—selective electrode induced better electrosorption than the conventional MCDI, whereas its salt adsorption capacity was lower than that of the ion-exchange (IX) layer only coated one. The mole fraction of NO3 adsorption kept increased even after saturation by replacing Cl adsorbed on the resin coating layer. However, the desorption efficiency of NO3 was retarded as it was exchanged with Cl and temporarily intercepted in the resin of the IX layer, during ion migration towards the bulk brine solution. 81.5% of NO3 was removed with better NO3 selectivity from real municipal wastewater, and a high concentration of NO3 brine was obtained through successive operation. However, the poorly selective NO3 desorption, which limits its enrichment due to the reverse ionic-strength gradient induced by the high concentration brine, needs to be mitigated to prove its effective recovery.

Original languageEnglish
Article number114425
JournalDesalination
Volume484
DOIs
Publication statusPublished - 2020 Jun 15

Keywords

  • Ion-exchange membrane
  • Membrane capacitive deionization
  • Nitrate selectivity
  • Resource recovery
  • Wastewater reuse

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Science(all)
  • Water Science and Technology
  • Mechanical Engineering

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