{
  "abstract": "Electrochemical pH-swing processes based on proton-coupled electron transfer (PCET) offer a promising route for selective chemical separation from aqueous media. Yet in all previous systems only one half of the pH swing performs a separation, while the reverse half is expended solely to regenerate the state of charge of the active electrode or electrolyte. Using a synthetic mimic of domestic wastewater as the input feed, we demonstrate a bidirectionally productive electrochemical pH-swing generated by a phenazine-carbon nanotube PCET-active composite electrode in an aqueous flow cell, in which both the acidifying and alkalizing half-cycles perform useful chemical separation. Electrode oxidation acidifies the wastewater to convert dissolved inorganic carbon into CO 2 (aq) for removal, whereas the subsequent reduction alkalizes the feed, converting NH 4 + to NH 3 (aq) for recovery using membrane stripping. An experimentally validated reaction-transport model establishes the pH-swing sequence as a key design parameter, with oxidation before reduction enabling integrated CO 2 removal and NH 3 recovery, whereas the opposite sequence prioritizes NH 3 recovery through near-complete NH 4 + -to-NH 3 conversion. The system achieved batchwise NH 3 recovery using the reduction–oxidation sequence over 31 cycles spanning 43 h, establishing operational stability over a duration not previously demonstrated for PCET-driven nutrient recovery. The oxidation–reduction sequence achieved average energetic costs of 219.9 kJ mol -1 CO 2 removed and 12.2 kWh kg -1 N recovered, with corresponding separation rates of 4.47 μmol CO 2 h -1 cm -2 and 5.33 g N m -2 day -1 , respectively. By making both directions of an electrochemical pH swing productive, this work reframes electrode regeneration as an opportunity for a second separation, and points toward wastewater treatment plants as distributed sites for combined nutrient recovery and carbon removal.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": null,
  "author_total": 4,
  "authors": [
    {
      "name": "Bin Yun",
      "orcid": "0009-0002-6672-7643"
    },
    {
      "name": "Orçun Dinçer",
      "orcid": "0000-0001-8144-4882"
    },
    {
      "name": "Marc-Antoni Goulet",
      "orcid": "0000-0002-9146-6759"
    },
    {
      "name": "David G. Kwabi"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/51k7fz94rt66t.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15008841/v1",
  "fulltext_url": null,
  "id": "51k7fz94rt66t",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008841/v1",
  "language": null,
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2305|Microbial Fuel Cells and Bioremediation"
    ]
  ],
  "openalex": "W7213322203",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv.15008841/v1",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-15",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/51k7fz94rt66t.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:19Z",
      "native_id": "10.26434/chemrxiv.15008841",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008841/v1"
    }
  ],
  "subjects": [
    {
      "field": "earth",
      "origin": "openalex:2305|Microbial Fuel Cells and Bioremediation",
      "subfield": "environmental-science"
    }
  ],
  "title": "Integrated CO2 removal and NH3 recovery from wastewater using a bidirectionally productive electrochemical pH swing",
  "title_text": "Integrated CO2 removal and NH3 recovery from wastewater using a bidirectionally productive electrochemical pH swing",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:19Z",
  "url": "https://research.draconitic.com/paper/51k7fz94rt66t",
  "venue": "ChemRxiv",
  "versions": []
}