Polyethylenimine-assisted preparation of Zr-MOF/GO membranes for radionuclide separation.

In this study, a zirconium-metal organic framework/graphene oxide (UiO-66-NH 2 /GO) nanofiltration membrane has been prepared with the assistance of branched polyethyleneimine (PEI). This PEI-assisted method facilitates a more uniform dispersion of UiO-66-NH 2 within the GO membrane, thereby enhancing the structural stability of the membrane during membrane separation. The as-prepared membrane has exhibited excellent performance in removing radioactive strontium ions, which is a trending research field in nuclear wastewater treatment. A comprehensive investigation into the separation mechanism of the PEI-UiO-66-NH 2 /GO membrane has revealed a synergistic effect involving size exclusion and electrostatic repulsion. Furthermore, the PEI-UiO-66-NH 2 /GO membrane has consistently achieved high strontium rejection across a wide range of strontium concentrations, pH levels, and even in the presence of other interfering ions. More significantly, the membrane has demonstrated remarkably enhanced capacity for selectively separating binary mixtures of cesium and strontium, offering practical relevance. Our results have indicated that the PEI-UiO-66-NH 2 /GO membrane holds considerable promise for the separation of strontium ions. [Display omitted] • The role of PEI in facilitating the formation of UiO-66-NH 2 /GO membrane is comprehensively studied. • PEI-UIO-66-NH 2 /GO membrane demonstrates enhanced water permeance and strontium rejection ratio compared to GO membrane. • The resulting membrane exhibits robust strontium separation performance across diverse testing conditions. • The resulting membrane shows great potential in selective separation of strontium and cesium. [ABSTRACT FROM AUTHOR]