Biosorption of uranium from aqueous solutions using a filamentous green macroalga: performances and mechanism

In response to the depletion of global uranium reserves and the radioactive contamination of wastewater, there is an urgent need to develop efficient, sustainable, and cost-effective uranium biosorbents. Herein, a green macroalga Rhizoclonium riparium was prepared for uranium (U(VI)) removal. The results showed that the maximum adsorption capacity of U(VI) was 80.96 mg g −1 (pH = 5, 298 K and 0.1 M NaNO 3 ). The kinetics, isotherms and thermodynamics analysis revealed that the adsorption process was chemisorption, homogeneous monolayer adsorption, endothermic and spontaneous. Through the mechanism characterization, it was proved the adsorbed of uranium on R. riparium was mainly controlled by the complexation between U(VI) and –OH, –COOH, –NH 2 . Besides, the R. riparium possess high selectivity towards uranium and good recycling performance. This work highlights new opportunities for biosorbents to be obtained directly from nature and used to remove radioactive contamination.