Unraveling the mechanism of iodate adsorption by anthocyanin-rich fruit waste as green adsorbents for Applications of radioactive iodine remediation in water environment
Issued Date
2024-06-01
Resource Type
ISSN
00139351
eISSN
10960953
Scopus ID
2-s2.0-85185600252
Pubmed ID
38365049
Journal Title
Environmental Research
Volume
250
Rights Holder(s)
SCOPUS
Bibliographic Citation
Environmental Research Vol.250 (2024)
Suggested Citation
Phanthuwongpakdee J., Babel S. Unraveling the mechanism of iodate adsorption by anthocyanin-rich fruit waste as green adsorbents for Applications of radioactive iodine remediation in water environment. Environmental Research Vol.250 (2024). doi:10.1016/j.envres.2024.118502 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/97401
Title
Unraveling the mechanism of iodate adsorption by anthocyanin-rich fruit waste as green adsorbents for Applications of radioactive iodine remediation in water environment
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Corresponding Author(s)
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Abstract
In aquatic settings, radioactive iodine from nuclear waste can exist as iodate (IO3−). This study explored the efficiency and mechanism of IO3− adsorption by minimally modified anthocyanin-based adsorbents. Pomegranate peels and mangosteen pericarps were selected from an initial screening test and could remove over 70% of 10 mg/L IO3−. The adsorbents yielded adsorption capacity (q) of 9.59 mg/g and 2.31 mg/g, respectively, at room temperature. At 5 °C, q values increased to 14.5 and 5.13 mg/g, respectively. Pomegranate peels showed superior performance, with approximately 4 times the anthocyanin content of mangosteen pericarps. Both adsorbents took 120 min to reach adsorption equilibrium, and no desorption was observed after 8 days (I-131 half-time). Confirmation of physisorption was indicated by the fit of the pseudo-first-order reaction model, negative entropy (exothermic), and negative activation energy (Arrhenius equation). IO3− inclusion was confirmed through adsorbent surface modifications in scanning electron microscope images, the increased iodine content post-adsorption in energy-dispersive X-ray spectroscopy analysis, and alterations in peaks corresponding to anthocyanin-related functional groups in Fourier transform infrared spectroscopy analysis. X-ray absorption near-edge spectroscopy at 4564.54 eV showed that iodine was retained in the form of IO3−. Through the computational analysis, electrostatic forces, hydrogen bonds, and π-halogen interactions were deduced as mechanisms of IO3− adsorption by anthocyanin-based adsorbents. Anthocyanin-rich fruit wastes emerged as sustainable materials for eliminating IO3− from water.