Mechanism of selective uranium adsorption using polyvinyl alcohol /Cyphos IL-101 / reduced graphene oxide composites

•The Kd value of APGO for U was 14.8 times higher than that for V.•The adsorption rate of U by APGO at pH 6–8 ranged from 98.6% to 96.4%.•APGO demonstrates excellent performance in dynamic adsorption.•APGO is suitable for the dynamic extraction of U from seawater. A novel composite material for uranium extraction from seawater, APGO, was prepared by crosslinking reduced graphene oxide (rGO) loaded with trihexyl(tetradecyl)phosphonium chloride (Cyphos IL-101) with polyvinyl alcohol. The experimental results indicate that the surface of APGO contains functional groups, such as carboxyl, hydroxyl, and phosphate, that have adsorption properties for uranium. APGO exhibits excellent hydrophilicity and stability while preserving the intact two-dimensional network structure of rGO. The specific surface area of APGO was 9.23 m2/g with an average pore size of 27.50 nm. Furthermore, the optimal pH range for APGO to adsorb uranium is 6–8, making it more suitable for extracting uranium from seawater. Notably, the selective adsorption capacity of APGO for uranium is significantly enhanced compared to that of AGO, with a Kd value approximately 4.6 times higher than that of AGO. The theoretical adsorption capacity is 467mg/g at 318 K (pH = 6). The process of uranium adsorption by APGO is a spontaneous endothermic reaction. The adsorption performance of APGO is noteworthy because it exhibits only a 2 % decrease after five adsorption–desorption cycles. Furthermore, APGO demonstrates commendable recyclability. Overall, APGO demonstrates a remarkable affinity for uranium and promising potential for efficiently extracting uranium from seawater.