Browsing by Author "Navarathna, Chanaka"

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    Application of biochar for the removal of actinides and lanthanides from aqueous solutions.
    (Elsevier Inc., 2022) Bursztyn, Amalia L. Fuentesa; Arwenyo, Beatrice; Nanney, Andie L.M.; Ramirez, Arissa; Jamison, Hailey; Venson, Beverly; Mohan, Dinesh; Mlsna, Todd E.; Navarathna, Chanaka
    Actinides and lanthanides are elements with unfilled f orbitals and are collectively labeled as the inner transition elements (ITEs). The actinide series includes 15 radioactive metallic ele ments with atomic numbers 89–103 (Cooper, 2000). The actinide elements are classified as light (Ac, Th, Pa, U, Np, Pu, Am) or heavy (Cm, Bk, Cf, Es, Fm, Md, No, Lr) based on their atomic numbers. The actinides fill their 5f sublevels progressively and exhibit char acteristics of both the d-block and the f-block elements. Elements of the actinide series can have oxidation states from +2 to plus +7. In addition to being radioactive, all actinides are paramagnetic and pyrophoric. Except for actinium with one oxidation state of +3, the other actinides are known to show variable oxidation states and more than one crystalline phase. To date, only the first four elements in the actinide series have been found to occur naturally.
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    Sorption of Phosphate on Douglas Fir Biochar Treated with Magnesium Chloride and Potassium Hydroxide for Soil Amendments
    (MDPI Processes, 2023-01-19) Arwenyo, Beatrice; Navarathna, Chanaka; Krishna, Naba Das; Hitt, Addie; Mlsna, Todd
    With increasing climate variability, a sustainable crop production approach remains an indispensable concern across the globe. In this study, P retention/availability of MgCl2.6H2O/KOH modified Douglas fir biochar was assessed. The MgCl2·6H2O/KOH treated Douglas fir biochar was prepared by sequentially treating Douglas fir biochar with magnesium chloride and potassium hy droxide solutions. The biochar’s surface area, pore volume, morphology, and elemental composi tions were determined using BET, SEM, SEM/EDS, and powder X-ray analyzes. Both surface area and pore volume were reduced by more than 97% following modification. Similarly, the morphol ogy and elemental compositions changed after modification. The maximum P adsorbed correspond ing to Langmuir–Freundlich model was 41.18 mg g−1 . P sorption on biochar soil mixture was pH dependent. More studies are required to establish the field applicability of P-laden MgCl2 ·6H2O/KOH-modified Douglas fir biochar as a soil additive.