{
  "abstract": "Conventional hydrothermal carbonization of biomass generally produces carbon dots (CD) with low yield and variable quality, mainly due to incomplete hydrolysis. This study evaluated how ultrasonication pretreatment and sequential pre/post-treatment influenced hydrothermal carbonization of Gracilaria fisheri and the properties of the resulting CD. Probe ultrasonication (Sonics VC750, 20 kHz, 13 mm probe) was applied to 50 mL suspensions at 20, 50, and 80% amplitude for cumulative ultrasonication-on time of 5 or 15 min, using 5 s on/5 s off pulses and ice-bath cooling. Hydrothermal carbonization was performed at 200 °C for 8 h. Recovered-solid yield and physicochemical parameters were used to select optimal conditions. Pre CD 80%/5min , which showed the highest yield and zeta-potential among Pre CD was selected for subsequent post-treatment. Pre/Post CD further increased the recovered-solids yield to 90.47% ( Pre/Post CD 80%/5min ). FTIR spectra confirmed the retention of oxygen-rich functional groups, while TEM images showed smaller, more dispersed particles following sequential treatment. Pre/Post CD 80%/5min exhibited stronger UV-C attenuation and excitation-dependent photoluminescence, whereas Pre CD 80%/5min showed greater photostability under 254 nm irradiation. Pre/Post CD 80%/5min exhibited the highest antioxidant activity, including an ABTS radical-scavenging activity of 68.03 mmol Trolox equivalent/mg and a metal-chelating ability of 0.13 mmol ethylenediaminetetraacetic acid equivalent/mg. All tested CDs exhibited minimum inhibitory concentrations of 3.50 mg/mL against Staphylococcus aureus , Listeria monocytogenes , Vibrio parahaemolyticus , and Pseudomonas aeruginosa . These findings demonstrate that the sonication sequence influenced the recovered-solids yield and bioactivities. The effects of ultrasonication on antioxidant and antibacterial activities warrant further investigation to clarify the associated changes in material properties and functionality. The produced CD requires validation in food applications and a safety assessment.",
  "abstract_shown": true,
  "affiliations": [
    "International Center of Excellence in Seafood Science and Innovation, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, Songkhla 90110, Thailand",
    "Faculty of Ocean Science and Technology, Kerala University of Fisheries and Ocean Studies, Kochi, Kerala 682506, India",
    "Division of Food and Nutritional Biotechnology, BRIC-National Agri-Food and Biomanufacturing Institute (NABI), Sector-81, Sahibzada Ajit Singh Nagar, Mohali, Punjab 140306, India",
    "Biopharmaceuticals Lab, Department of Biotechnology, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur, Chennai, Tamil Nadu 603203, India",
    "ICAR-Central Institute of Fisheries Technology, CIFT Junction, Matsyapuri P.O, Willingdon Island, Kochi, Kerala 682029, India",
    "International Center of Excellence in Seafood Science and Innovation, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, Songkhla 90110, Thailand; Corresponding author."
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 6,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Arunachalasivamani Ponnusamy"
    },
    {
      "affs": [
        1
      ],
      "name": "S.R. Radhika Rajasree"
    },
    {
      "affs": [
        2
      ],
      "name": "Shivraj Nile"
    },
    {
      "affs": [
        3
      ],
      "name": "Rasool Abdul Nazeer"
    },
    {
      "affs": [
        4
      ],
      "name": "George Ninan"
    },
    {
      "affs": [
        5
      ],
      "name": "Soottawat Benjakul"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/3ymnk4zcgg24m.bib",
  "cited_by": 0,
  "doi": "10.1016/j.ultsonch.2026.108106",
  "fulltext_url": "http://www.sciencedirect.com/science/article/pii/S1350417726003718",
  "id": "3ymnk4zcgg24m",
  "issns": [
    "1350-4177",
    "1873-2828"
  ],
  "landing_url": "https://doi.org/10.1016/j.ultsonch.2026.108106",
  "language": "en",
  "licence": "CC-BY-NC-4.0",
  "licence_label": "CC BY-NC 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "VSI : Ultrasound Synthesis of Carbon-Based Nanomaterials"
    ],
    [
      "lcc",
      "QC221-246"
    ],
    [
      "lcc",
      "QD1-999"
    ],
    [
      "openalex",
      "1104|Seaweed-derived Bioactive Compounds"
    ]
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  "openalex": "W7221358966",
  "pdf_url": "https://www.sciencedirect.com/science/article/pii/S1350417726003718/pdf",
  "pmcid": "PMC13715405",
  "pmid": "42913176",
  "published": "2026-10-10",
  "publisher": "Elsevier",
  "ris": "https://research.draconitic.com/paper/3ymnk4zcgg24m.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T13:44:29Z",
      "native_id": "2a3a4b233f0e45148b37642a6d52fa89",
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      "url": "https://doi.org/10.1016/j.ultsonch.2026.108106"
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    {
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  "subjects": [
    {
      "field": "biology",
      "origin": "openalex:1104|Seaweed-derived Bioactive Compounds",
      "subfield": "ecology"
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  ],
  "title": "Ultrasonication-assisted carbonization of",
  "title_text": "Ultrasonication-assisted carbonization of",
  "type": "peer-reviewed",
  "updated_at": "2026-11-01T12:22:43Z",
  "url": "https://research.draconitic.com/paper/3ymnk4zcgg24m",
  "venue": "Ultrasonics Sonochemistry",
  "versions": []
}