McGowan, S. and Zhang, H. and Degueldre, C. (2022) Testing sorption of uranium from seawater on waste biomass : A feasibility study. Fuel, 315: 123224. ISSN 0016-2361
Experimental_paper_St_H_Cl_21_10_2021_revised_txt_B_W.pdf - Accepted Version
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Abstract
The extraction of uranium from seawater has been successfully performed in batch mode on 15 selected biomaterials, including fruit, green vegetable and tuber samples. Theses biomaterial samples were contacted in static batches with Irish seawater (2.8 ppb U) for periods of 1–2 months. After sorption, both supernatants and HNO3 digests from the sorbed biomass were analysed by inductively coupled plasma mass spectroscopy (ICP-MS) for uranium. Sorption of uranium from seawater onto the following materials revealed loadings (µg kg−1) increases from 10 to 20 for diced potato (Solanum tuberosum), Sultanas grape (Vitis vinifera), Brussels sprouts (Brassica oleracea), and sweet potato (Ipomoea batatas), to 200–300 for skin of nectarine (Prunus Persica), of orange (Citrus Sinensis) and of potato (Solanum tuberosum). The fraction of sorbed uranium reached 92% to 98% for peanut shell, orange skin, Brussels sprouts, garlic, grape pulp, grape skin, and Sultanas grape. Consequently the Kd values were of the order of 50 to 200 mL g−1 for mange tout (Pisum sativum), sweet potato (Ipomoea batatas) whole, potato (Solanum tuberosum) whole, Brussels sprouts (Brassica oleracea) and nectarine (Prunus Persica) skin, of 200 to 1000 mL g−1 for grape (Vitis vitaceae) pulp, Sultanas (Vitis vinifera) grape, peanut (Arachis hypogaea) shell, kale (Brassica oleriaceae), lemon skin and grape (Vitis vinifera) skin, and finally of 1000–2000 mL g−1 for potato (Solanum tuberosum) skin, orange (Citrus Sinensis) skin and garlic (Allium sativum). Polyphenols are expected to increase sorption. The plot of Kd with polyphenol concentration displays a positive correlation. Increases in sorption of may also be due to U(VI) reduction in U(IV) by antioxidants reported on these biomaterials and by colloidal aggregation, suggesting irreversible sorption. This screening study aimed to select specific bio-waste material absorbents to be tested in detail in a future study, prior tests at the pilot scale.