Membrane Adsorbers\nwith Copolymer Coatings for the\nSeparation of Actinides from Lanthanides (UO<sub>2</sub><sup>2+</sup> and La<sup>3+</sup>)

Separating lanthanides from actinides is a common task\nin rare\nearth element mining and processing, medical isotope purification,\nnuclear forensics, and radioanalytical chemistry. Membrane adsorbers\nare emerging as a promising platform to perform such adsorptive separations.\nIn this work, functional membrane adsorbers are synthesized by coating\npoly(ether sulfone) microfiltration membranes with polymeric ligands\nthat contain ethylene glycol methacrylate phosphate (EGMP) as the\nion-coordinating moiety. The composition of the polymeric ligands\nis controlled by copolymerizing EGMP with butyl methacrylate (BuMA)\nand 2-hydroxy ethyl methacrylate (HEMA). Equilibrium and time-resolved\nadsorption data were modeled to understand the thermodynamics and\nkinetics of complexation of UO<sub>2</sub><sup>2+</sup> at pH 1 and\npH 4. The data are compared to previously reported data for La<sup>3+</sup> and the feasibility of on-column separation of UO<sub>2</sub><sup>2+</sup> over La<sup>3+</sup> is assessed by transport modeling\nin MATLAB. All synthesized membranes are selective for UO<sub>2</sub><sup>2+</sup> over La<sup>3+</sup>. At pH 1, the separation is improved\nwith the presence of a nonbinding comonomer. At pH 4, the separation\nis worsened by the presence of a nonbinding comonomer.