Bimetallic Zn/Co-ZIF tubular membrane for highly efficient pervaporation separation of Methanol/MTBE mixture

Preparation of defect-free and stable metal-organic framework tubular membrane for liquid separation is still a great challenge. In this work, a high-quality bimetallic Zn/Co-ZIF tubular membrane was fabricated via a novel strategy on a porous ceramic tube for the highly efficient separation of methanol (MeOH)/methyltert-butylether (MTBE) mixture by pervaporation. The strategy includes first the introduction of a thinlayer of Zn/Co hydroxy double salts (HDSs) on the tube surface and then the facile conversion of the HDS layer to a dense and stable bimetallic Zn/Co-ZIF membrane. The achieved membrane can preferentially separate MeOH from the 15 wt% MeOH/MTBE mixture and display an ultrahigh separation performance with flux of 1.96 kg m−2 h−1 and separation factor of 6985. It can also demonstrate an excellent long-term operating stability benefited from the HDS layer acting as an inorganic linker. Therefore, the bimetallic Zn/Co-ZIF membrane has great industrial application potential for the separation of MeOH/MTBE mixture.