Construction of Ion-Imprinted Graphene Oxide Mixed-Matrix Membranes for Selective Adsorption and Separation of Tm.

Efficient adsorption and separation of rare earth from other similar rare earth wastewater has become an urgent demand for resource utilization of ion-type rare earth minerals in China. Herein, thulium (Tm) ion-imprinted graphene oxide (GO)-doped polyether sulfone (PES) membranes (GO-TII/PES-2 membranes) were prepared, in which ion-imprinted graphene oxide was applied as an efficient Tm ionic ligand in the imprinted layer and polyether sulfone was applied as a carrier in the membrane matrix to achieve the selective adsorption and separation of Tm and neighboring rare earth ions. Combined with an ion rectifier, the separation and purification performances of Tm were explored. The separation factors β, β(, β and β in the dynamic adsorption process increased significantly from 1.22, 1.04, 1.04, and 1.02 for nonimprinting to 3.07, 3.91, 3.91, and 3.33 for imprinted membranes. The GO-TII/PES-2 membrane adsorbed about three times more Tm than the nonionic-imprinted (GO-NII/PES) membrane by adding a color developer and quantifying Tm based on a fast and easy UV-photometric method. After eight dynamic permeations, the adsorption of Tm by the GO-TII/PES-2 membrane decreased by only 13%, indicating that the membrane has good reuse performance. Additionally, the investigation examined the influence of Tm on wheat seed germination, underscoring its potential application in agriculture and the importance of adsorbing and separating rare earth ions.