Biomass aerogel based on chitosan and bayberry tannin for uranium recovery from aqueous solution

Here, a biomass aerogel (CS-BT) is prepared by the facile cross-linking of chitosan and bayberry tannins with glutaraldehyde. U(VI) can be adsorbed by hydroxyl groups on CS-BT aerogel via chelation, and the maximum adsorption capacity of the obtained aerogel to U(VI) is ~140 mg g-1 and the removal rate reaches up to 99% (at 298.15 K, pH = 5.0). The pseudo-second-order kinetics model and Freundlich model can better match the adsorption process of CS-BT aerogel, implying that its adsorption is a chemical adsorption process dominated by multilayer adsorption. The thermodynamic results show that the adsorption process of U(VI) by CS-BT aerogel is spontaneous and exothermic. Hence, our biomass aerogel can effectively extract uranium from water, contributing to the sustainable development of the nuclear industry.