{
  "abstract": "Duck bone, an under-used by-product of Southeast Asian poultry processing, was converted into hydroxyapatite-based bone char by single-step, reagent-free pyrolysis at 300, 400, and 500 °C and evaluated as a reusable Cu(II) adsorbent. Physical and chemical analyses showed progressive removal of the collagen–lipid matrix and preservation of a hydroxyapatite scaffold (98–99 wt% of the crystalline phases by Rietveld refinement, with minor calcite; apparent crystallite size ~7–8 nm across and ~23–25 nm along the c-axis). Surface area increased progressively from 33.0 to 84.2 m2 g−1 with pyrolysis temperature, whereas the Toth capacity increased steadily from 44.7 to 48.6 mg g−1, indicating that uptake is governed mainly by apatite-site accessibility rather than scaling proportionally with surface area. Sigmoidal Avrami kinetics with exponents of 1.25–1.48, sharply saturating isotherms, an endothermic enthalpy of 71–90 kJ mol−1, and points of zero charge of about pH 7–9.5 supported cooperative binding through Ca2+–Cu2+ ion exchange, phosphate and hydroxyl complexation, and proposed surface nucleation of Cu–phosphate clusters; Cu(OH)2 precipitation was not expected at the pH used. After five HCl regeneration cycles, DKB retained 73.1–80.0% of its initial efficiency, and the first-order decay constant decreased from 0.078 to 0.056 cycle−1 with increasing pyrolysis temperature. DKB produced at 500 °C combined the highest capacity, fastest kinetics, and greatest regeneration stability, establishing duck bone as a low-cost, circular feedstock for Cu(II) remediation.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Mechanical Engineering, Faculty of Arts and Science, Chaiyaphum Rajabhat University, Chaiyaphum 36000, Thailand",
    "School of Energy and Environment, University of Phayao, Phayao 56000, Thailand",
    "Department of Environmental Health, Faculty of Public Health, Burapha University, Chonburi 20131, Thailand",
    "Field of Environmental Engineering, Faculty of Engineering, Mahasarakham University, Mahasarakham 44150, Thailand"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 8,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Sukanya Hongthong",
      "orcid": "0009-0009-8859-8994"
    },
    {
      "affs": [
        1
      ],
      "name": "Torpong Kreethachat"
    },
    {
      "affs": [
        1
      ],
      "name": "Saksit Imman",
      "orcid": "0000-0002-1149-1277"
    },
    {
      "affs": [
        1
      ],
      "name": "Nopparat Suriyachai",
      "orcid": "0000-0002-4097-5625"
    },
    {
      "affs": [
        1
      ],
      "name": "Anusorn Boonpoke",
      "orcid": "0000-0002-3161-0915"
    },
    {
      "affs": [
        2
      ],
      "name": "Kowit Suwannahong",
      "orcid": "0000-0002-3632-6227"
    },
    {
      "affs": [
        3
      ],
      "name": "Pattaranun Maskhunthod"
    },
    {
      "affs": [
        3
      ],
      "name": "Surachai Wongcharee",
      "orcid": "0000-0002-5687-4562"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/f5w93zj82g8ky.bib",
  "cited_by": 0,
  "doi": "10.3390/ijms27219991",
  "fulltext_url": null,
  "id": "f5w93zj82g8ky",
  "issns": [
    "1422-0067"
  ],
  "landing_url": "https://www.mdpi.com/1422-0067/27/21/9991",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [],
  "openalex": null,
  "pdf_url": null,
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-07",
  "publisher": "MDPI AG",
  "ris": "https://research.draconitic.com/paper/f5w93zj82g8ky.ris",
  "sources": [
    {
      "first_seen": "2026-11-10T00:21:27Z",
      "native_id": "10.3390/ijms27219991",
      "source": "crossref",
      "url": "https://www.mdpi.com/1422-0067/27/21/9991"
    }
  ],
  "subjects": [
    {
      "field": "biochemistry",
      "origin": "issn:1422-0067",
      "subfield": "general"
    }
  ],
  "title": "Valorizing Duck Bone into Regenerable Hydroxyapatite Biochar: Pyrolysis Effects on Divalent Heavy Metal Adsorption Mechanisms",
  "title_text": "Valorizing Duck Bone into Regenerable Hydroxyapatite Biochar: Pyrolysis Effects on Divalent Heavy Metal Adsorption Mechanisms",
  "type": "peer-reviewed",
  "updated_at": "2026-11-10T00:21:27Z",
  "url": "https://research.draconitic.com/paper/f5w93zj82g8ky",
  "venue": "International Journal of Molecular Sciences",
  "versions": []
}