A Defect-Induced In Situ Phosphorylation Strategy of Molybdenum Disulfide: Structural Modification and Uranium Adsorption Performance Enhancement

The development of superior adsorbents that can achieve efficient, fast, and highly selective U(VI) separation for practical applications remains a challenge. MoS2 has great potential for U(VI) adsorption owing to its two-dimensional layered structure and abundant active sulfur sites. Herein, a novel few-layered Pd–MoS2–PO4 with high-density marginal sulfur and phosphoric group active sites was synthesized by using a combined strategy involving molten salt electrolysis and defect-induced in situ phosphorylation. By adjusting the in situ Pd and phosphoric acid concentrations, the phosphoric group concentration and the corresponding adsorption activity can be controlled. 0.5Pd–MoS2–PO4 nanosheets exhibit ultrafast adsorption (equilibrium is reached within only 3 min) and ultrahigh adsorption capacity (416.62 mg/g), surpassing those of most previously reported modified MoS2 and other materials. Moreover, the adsorption process is best fitted with the pseudo-second-order kinetic model and Langmuir isotherm model, indicating the occurrence of heterogeneous chemisorption. 0.5Pd–MoS2–PO4 exhibits ultrahigh selectivity to U(VI) (selective adsorption capacity (SU) > 59.1%). The excellent adsorption properties of 0.5Pd–MoS2–PO4 are closely related to its unique structural characteristics, including a large surface area, abundant porosity, excellent chemical stability, and high-density, marginal sulfur, and phosphoric group active sites. Furthermore, 0.5Pd–MoS2–PO4 is well suited for highly efficient and selective U(VI) recovery from radioactive wastewater, indicating its potential for practical applications.