New Chemistry for Mixed Matrix Membranes: Growth of Continuous Multilayer UiO-66-NH2 on UiO-66-NH2-Based Polyacrylonitrile for Highly Efficient Separations

This paper describes a new architecture of mixed matrix membranes (MMMs), taking full benefit of the functionalities of a metal–organic framework (MOF). NH 2 -functionalized zirconium carboxylate MOF (UiO-66-NH 2 ) nanocrystals were solvothermally synthesized on a polyacrylonitrile membrane using an in situ growth route. The structure and filtration properties of UiO-66-NH 2 -based MMMs with different concentrations of Zr-MOF were studied, in which a Zr-MOF loading of 1 and 2 wt % was selected for further modification. The seeded strategy was then used to prepare a continuous and defect-free multilayer of UiO-66-NH 2 loaded on UiO-66-NH 2 -based MMMs by repeating the solvothermal in situ growth. As a showcase, the filtration results demonstrated that the two-layer continuous UiO-66-NH 2 loaded on 2 wt % UiO-66-NH 2 -based MMM separates Rh.B molecule dye from water on the size exclusion basis and electrostatic repulsion (flux of water 68 L/m 2 h and rejection factor up to 92%).