Phospho-Enriched amidoxime adsorbents utilizing synergistic multifunctional groups for enhanced uranium removal from wastewater

Efficient removal of uranium from radioactive wastewater is paramount for the sustainable development of nuclear energy. However, the exploitation of superior adsorbents with practical applications remains a challenge. In this work, we engineered and synthesized an adsorbent (TPEAC) enriched with phosphine-oxime, featuring a matrix composed of hydrophilic modified amidoxime functional groups. TPEAC exhibited exceptional selectivity (Multiple ion coexistence R% ˃ 99 %) and efficiency in uranium adsorption, with a higher adsorption rate (around 400 mins) and capacity (243.9 mg/g) than pure amidoxime (133.3 mg/g) and modified-amidoxime (175.4 mg/g) materials. Moreover, it maintained robust stability and reusability even after six adsorption–desorption cycles, with removal ratio still above 95 %. In-depth mechanistic investigations through DFT and XPS elucidated that P-O (P = O) groups exhibited a stronger affinity for U(VI) compared to other functional groups, and the adsorption of TPEAC towards U(VI) primarily due to the synergistic interaction among P-O (P = O) groups, C(NH2) = N-OH, and carboxyl groups, which significantly facilitated the effective removal of U(VI). Most prominently, TPEAC performed considerable potential in processing actual uranium mine wastewater, with its dynamic column device achieving a U(Ⅵ) recovery up to 99.6 %. This work not only furnishes an efficacious and economical solution for uranium wastewater treatment but also provides new approaches for scalable application uranium materials.