Selective Molecular Separation on Ti3C2Tx-Graphene Oxide Membranes during Pressure-Driven Filtration: Comparison with Graphene Oxide and MXenes

Abstract

In this work, we prepared 90 nm thick Ti3C2Tx-graphene oxide (GO) membranes laminated on a porous support by mixing GO with Ti3C2Tx. This process was chosen to prevent the penetration of target molecules through inter-edge defects or voids with poor packing. The lattice period of the prepared membrane was 14.28 angstrom, as being swelled with water, resulting in an effective interlayer spacing of around 5 angstrom, which corresponds to two layers of water molecules. The composite membranes effectively rejected dye molecules with hydrated radii above 5 angstrom, as well as positively charged dye molecules, during pressure-driven filtration at bar. Rejection rates were 68% for methyl red, 99.5% for methylene blue, 93.5% for rose Bengal, and 100% for brilliant blue (hydrated radii of 4.87, 5.04, 5.88, and 7.98 angstrom, respectively). Additionally, the rejections of composite membrane were compared with GO membrane and Ti3C2Tx membrane.