A versatile MOF liquids-based Janus fibrous membrane towards complex oil/water separation and heavy metal ions removal

As an emerging material, porous liquids (PLs) have attracted wide attention and are applied in oily wastewater for the effective elimination of heavy metal ions due to their permanent pore structure, mobility, and superhydrophilicity. However, it remains a challenge to further enhance the separation performance of PLs. Here, a novel metal–organic framework (MOF) porous liquid was synthesized and mixed with a polyacrylonitrile (PAN) solution to produce an asymmetrical Janus fibrous membrane by electrostatic spinning technique. Benefiting from the synergistic effect of the electric field and self-migrating properties of MOF PLs, the Janus membranes exhibited ultrahigh flux of 25310.26 L m-2h−1 bar−1, outstanding separation efficiency (reaching up to 99.99 %) in various oil–water emulsions and high antimicrobial activity (>99.9 %). More impressively, the obtained Janus membranes maintained long-term stability, with separation efficiencies consistently as high as 99.5 %. Meanwhile, the porous structure of MOF PLs with abundant active sites and affinity of polyethylene glycol (PEG) flexible chain for metal ions facilitates the adsorption of metal ions with a maximum equilibrium adsorption capacity of 205 mg/g, which is superior to other literature reported. These results demonstrated that the versatile MOF PLs-based Janus fibrous membranes had a promising application prospect in addressing the challenges associated with such wastewater treatment.