{
  "abstract": "Directional solvent extraction (DSE) recovers water from brine with low-temperature heat, and its output depends on how much water the solvent takes up on heating and releases on cooling. In an ionic liquid (IL) solvent, adding a hydrophilic co-anion is one way to tune this behavior. Here we screened co-anions X in 5:1 mixtures of cholinium bis(trifluoromethylsulfonyl)imide ([Choline][NTf2]) with [Choline][X] and selected dihydrogen phosphate. We followed liquids with nominal [NTf2] : [H2PO4] ratios of 5:1, 10:1 and 20:1 over five extraction cycles and determined the freshwater yield (FWY) of each run from the mass of the phase collected after cooling. Every run with these liquids had an FWY above the ≈ 0.30 wt% ◦C−1 reported for 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide and the ≈ 0.31 wt% ◦C−1 reported for a hydroxide-containing cholinium formulation. FWY was 0.35–0.38 wt% ◦C−1 in the first cycle. When the recovered liquids were reused, it rose to 0.55–0.58 wt% ◦C−1 in the second or third cycle and then declined to 0.40–0.49 wt% ◦C−1 in the fourth and fifth cycles. In molecular dynamics simulations, dihydrogen phosphate interacted strongly with water, as reported for hydroxide, and was enriched around water relative to its share of the anions.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Aerospace and Mechanical Engineering",
    "University of Notre Dame",
    "Department of Chemistry and Biochemistry",
    "Department of Chemical and Biomolecular Engineering"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 7,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Guoyue Xu"
    },
    {
      "affs": [
        2,
        1
      ],
      "name": "Andrew Wise"
    },
    {
      "affs": [
        2,
        1
      ],
      "name": "Jiyoon Kim"
    },
    {
      "affs": [
        2,
        1
      ],
      "name": "Kuang Gu"
    },
    {
      "affs": [
        3,
        1
      ],
      "name": "Yong Zhang"
    },
    {
      "affs": [
        2,
        1
      ],
      "name": "Brandon L. Ashfeld",
      "orcid": "0000-0002-4552-2705"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Tengfei Luo"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/8yks3ptr6k239.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15009828/v1",
  "fulltext_url": null,
  "id": "8yks3ptr6k239",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009828/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",
      "1503|Ionic liquids properties and applications"
    ]
  ],
  "openalex": "W7220452881",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv.15009828/v1",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-04",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/8yks3ptr6k239.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:22Z",
      "native_id": "10.26434/chemrxiv.15009828",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009828/v1"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "openalex:1503|Ionic liquids properties and applications",
      "subfield": "catalysis"
    }
  ],
  "title": "Dihydrogen Phosphate as a Hydrophilic Co-Anion in Multicomponent Cholinium Ionic Liquids for Directional Solvent Extraction",
  "title_text": "Dihydrogen Phosphate as a Hydrophilic Co-Anion in Multicomponent Cholinium Ionic Liquids for Directional Solvent Extraction",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:22Z",
  "url": "https://research.draconitic.com/paper/8yks3ptr6k239",
  "venue": "ChemRxiv",
  "versions": []
}