Cyphos IL101 enhancement on uranium extraction from seawater of SA/rGO/PEI gel beads and regulation optimal adsorption conditions of pH

Herein, novel sodium alginate/Cyphos IL101–loaded reduced graphene oxide/polyethyleneimine (SPGO; Cyphos IL101 = trihexyl (tetradecyl) phosphonium chloride) gel beads were prepared for highly selective extraction of uranium (U) resources from seawater. Results revealed that seawater pH (pH = 8) was the best adsorption condition for SPGO usage, and the adsorption rate of U reached >97 %. Further, in simulated seawater adsorption tests, the distribution coefficient of U was considerably higher than those of coexisting ions. In addition, U adsorption by SPGO, which was chemical adsorption, occurred via a spontaneous endothermic reaction. Mechanism studies revealed that carboxyl, hydroxyl, amino, and phosphate groups on the SPGO surface were involved in U adsorption. The addition of Cyphos IL101 significantly improved the selective adsorption performance of SPGO for U in seawater, and SPGO demonstrated excellent recycling capabilities. Thus, SPGO shows great potential for extracting U from seawater. •The optimum adsorption pH of SPGO for U after Cyphos IL101 loading was 8.•Loading of Cyphos IL101 improved the adsorption selectivity of SPGO for U.•The maximum distribution coefficient ratio of SPGO to U–vanadium was 15.6.