Surface modification route to prepare novel polyamide@NH2_MIL-88B nanocomposite membranes for water treatment

Abstract

The surface modification of support membranes is an important approach for the preparation of polyamide (PA) thin-film nanocomposite membranes with nanoporous materials embedded in PA. A surface modification route is reported to fabricate novel PA nanocomposite membranes incorporating amino-functionalized MIL type metal–organic framework materials (NH₂_MIL-88B). The support membrane was modified to grow an interlayer of NH₂_MIL-88B nanoparticles on the support surface, and then a PA layer was coated on the NH₂_MIL-88B interlayer, affording PA@NH₂_MIL-88B nanocomposite membranes. The prepared PA and PA@NH₂_MIL-88B membranes were characterized to investigate the physicochemical properties of the membrane structures and their separation performance for removing phenol from water. The surface modification route resulted in selective layers of the PA@NH₂_MIL-88B membranes that were less cross-linked, thinner and more hydrophilic than pure PA membranes. The membrane performance is improved by the water-preferential pathways of NH₂_MIL-88B, the defect-free nanocomposite layer of PA@NH₂_MIL-88, and decreases in the cross-linking degree and membrane thickness. The PA@NH₂_MIL-88B membranes showed significantly enhanced fluxes with high rejections (about 91 to 92%) and exhibited good durability. The reported approach can be further applied in the preparation of other polymer nanocomposite membranes with high performance.