Physicochemical Behavior of Uranium and Lanthanum in the Presence of Abies religiosa Leaf Biomass
2020
Jiménez-Reyes, M. | de M. Ramírez De La Cruz, F. | Solache-Ríos, M.
The biomass from Abies religiosa was conditioned and characterized. The adsorption kinetic data indicated sorbate-adsorbent interaction by chemical bonds. The maximum adsorption capacity of the biomass is four times higher for U(VI) (44.7 ± 0.3 mg g⁻¹) than La(III) (12.7 ± 0.2 mg g⁻¹). The pHₑq tends to the point of zero charge of the biomass. These adsorption capacities decreased as both the biomass dosage and ionic strength increased. The adsorption is a spontaneous and exothermic process. Adsorption may be due to the bonding of the metal ions to hydroxyl and carbonyl groups of the biomass. The fluorescence spectra of the U(VI) biomass reveal indirectly the presence of uranyl ions and it suggests an energy transfer from the uranyl to the biomass forming a bond of ionic character. Moreover, the unusual fluorescence of the uranyl solutions after contact with the biomass indicates the coexistence of uranyl(V) with uranyl(VI).
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