Enhanced performance in uranium extraction by the synergistic effect of functional groups on chitosan-based adsorbent

In this study, a novel sponge phosphoric acid functionalized porous composite adsorbent (named SPCCHC) was prepared from chitosan and chlorella hydrothermal charcoal. Kinetics and thermodynamics experiments showed that the theoretical maximum adsorption capacity of SPCCHC to U(VI) is 579.27 mg/g (288 K, pH = 6.5), indicating a spontaneous exothermic reaction. SPCCHC showed good adsorption selectivity for uranium in the adsorption studies of simulated seawater and a mixed solution of uranium-vanadium. The characterization of SPCCHC before and after U(VI) adsorption proves that the introduction of the phosphate group can greatly improve the adsorption effect of the adsorbent on uranium, particularly the distribution coefficients of uranium and vanadium differ by up to 89.5 times. At the same time, SPCCHC has good recycling performance, which is expected to be used in natural seawater uranium extraction.