Abstract: This study employed electrostatic spinning technology combined with solidphase separation to regulate the microstructure of a polyacrylonitrile（PAN） nanofiber basal membrane. Polymethylmethacrylate（PMMA） was added as a porogen. After amidoximation, a hierarchically porous nanofiber adsorption（PM-PAO-F） membrane was obtained for uranium（U） extraction from seawater. The adsorption kinetics, thermodynamics, and underlying mechanisms were subsequently investigated through a series of characterizations and experiments. The results showed that using PMMA as a porogen successfully generated secondary pores on the nanofiber surface. Consequently, the specific surface area of the PAN-based membrane increased from 8.87 to 22.94 m2/g, and the U（VI） adsorption capacity of the PAO adsorption membrane increased from 25.0 to 51.2 m~2/g under identical conditions. The adsorption kinetics and thermodynamic analyses revealed that the U（VI） adsorption by PM-PAO-F was endothermic. Fitting the experimental data to the Langmuir adsorption isotherm and the pseudo-second-order kinetic model indicated that the adsorption proceeds was uniform monolayer chemisorption. Moreover, the PM-PAO-F membrane retained 88% of its initial adsorption capacity after 12 cycles, highlighting its practical potential.

Key words: uranium（U） extraction from seawater, electrostatic spinning, solid-phase separation, hierarchical porous nanofiber, amidoxime