Adsorptive recovery of UO22+ from aqueous solutions using collagen-tannin resin

Collagen-tannin resin (CTR), as a novel adsorbent, was prepared via reaction of collagen with black wattle tannin and aldehyde, and its adsorption properties to UO22+ were investigated in detail, including pH effect, adsorption kinetics, adsorption equilibrium and column adsorption kinetics. The adsorption of UO22+ on CTR was pH-dependent, and the optimal pH range was 5.0-6.0. CTR exhibited excellent adsorption capacity to UO22+. For instance, the adsorption capacity obtained at 303 K and pH 6.0 was as high as 0.91 mmol UO22+/g when the initial concentration of UO22+ was 1.0 mmol/L. In kinetics studies, the adsorption equilibrium can be reached within 300 min, and the experimental data were well fitted by the pseudo-second-order rate model, and the equilibrium adsorption capacities calculated by the model were almost the same as those determined by experiments. The adsorption isotherms could be well described by the Freundlich equation with the correlation coefficients (R2) higher than 0.99, the adsorption behaviors of UO22+ on CTR column were investigated as well. Present study suggested that the CTR can be used for the adsorptive recovery of UO22+ from aqueous solutions.