{
  "abstract": "Nitrogen and phosphorus nutrient recovery from wastewater represents a critical frontier for circular fertilizer manufacturing and effective water treatment. Conventional chemical precipitation remains hindered by the need for expensive reagent consumables. Here, we examine an integrated, chemical-free electrochemical mixer (ECM) system that leverages selective bipolar membrane electrodialysis (SBED) to achieve precise struvite (MgNH4PO4 · 6H2O) crystallization. We furthermore demonstrate how control over current density (1–5 mA cm−2), specific charge loading (20–40 C m−3), and hydraulic retention time (τ = 2.3–6.9 s) enhances downstream crystallization yield, purity, and morphology. Shortening retention promotes boundary-layer convection, reducing in-cell scaling energy penalty (∆E) by 86% and total stack energy consumption by 22%. Operating within an optimized pH window (7.7 < pH < 9.0) governs crystal morphology and allows for 91% yield of highly pure struvite (> 97%), bypassing competitive newberyite crystallization. We unify the ECM transport kinetics and crystallization thermodynamics into a single dimensionless descriptor—the crystallization index—which establishes a linear correlation to predict the product yield based on upstream transport dynamics. Steady specific energy consumption of 9.38 ± 0.9 kWh kg−1 − struvite through autonomous in-situ acid flushing confirms system stability with minimal scaling. Finally, techno-economic analysis evaluates the levelized cost of struvite produced as $996 t−1, which is a reduction in operating expenditures by a maximum of 89% compared to commercial phosphorus recovery installations. Ultimately, the ECM eliminates crystallization chemical dependencies and reduces membrane scaling bottlenecks, establishing a highly tunable and efficient separations reactor with precise control of crystal products.",
  "abstract_shown": true,
  "affiliations": [
    "School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive NW, Atlanta, GA, 30332",
    "George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 770 Ferst Drive NW, Atlanta, GA, 30332"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 4,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Hyuck Joo Choi"
    },
    {
      "affs": [
        0
      ],
      "name": "Spandan Mondal"
    },
    {
      "affs": [
        0
      ],
      "name": "Mohammed Tahmid"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Marta C. Hatzell",
      "orcid": "0000-0002-5144-4969"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/f0sa8q3f7tzrm.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15009873/v1",
  "fulltext_url": null,
  "id": "f0sa8q3f7tzrm",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009873/v1",
  "language": null,
  "licence": "CC-BY-NC-ND",
  "licence_label": "CC BY-NC-ND",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2311|Phosphorus and nutrient management"
    ]
  ],
  "openalex": "W7220423800",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv.15009873/v1",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-05",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/f0sa8q3f7tzrm.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:22Z",
      "native_id": "10.26434/chemrxiv.15009873",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009873/v1"
    }
  ],
  "subjects": [
    {
      "field": "earth",
      "origin": "openalex:2311|Phosphorus and nutrient management",
      "subfield": "environmental-science"
    }
  ],
  "title": "Electrochemically Controlled Crystallization Using Selective Bipolar Membrane Electrodialysis",
  "title_text": "Electrochemically Controlled Crystallization Using Selective Bipolar Membrane Electrodialysis",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:22Z",
  "url": "https://research.draconitic.com/paper/f0sa8q3f7tzrm",
  "venue": "ChemRxiv",
  "versions": []
}