Rational Design of High-Flux, Eco-Friendly, and Versatile Superhydrophobic/Superoleophilic PDMS@ZIF-7/Cu(PO) Mesh with Self-Cleaning Property for Oil-Water Mixture and Emulsion Separation.

In recent years, efficient oil-water separation has gradually become an indispensable part of environmental treatment. Superhydrophobic/superoleophilic materials with excellent self-cleaning performance are urgently required and remain challenging in the investigation of practical, rapid, and efficient separation of oil-water mixture and emulsion, especially those with robust surfaces that can be used in harsh conditions. In this work, a novel superhydrophobic/superoleophilic material was first fabricated by in situ constructing PDMS@ZIF-7/Cu(PO) hierarchical architectures on a copper mesh, which was adopted as a high flux and efficient separation material for gravity-driven separation of oil-water mixture as well as emulsion. The introduction of crucial Cu(PO) nanosheet interlayers created the ideal hierarchical structures and serve as partial templates for the subsequent in situ growth of hydrophobic ZIF-7 nanosheets. An improved superhydrophobicity (CA = 155°), permeation flux (102,000 L m h), and preferred self-cleaning property were thus achieved by such manipulation of the copper mesh. The PDMS@ZIF-7/Cu(PO) mesh exhibited exceptional separation efficiency for diverse oil-water mixtures and emulsions attributed to the superhydrophobicity and the demulsification ability and considerable stability to cope with extreme environments including sunlight resistance, low temperature, and corrosion resistance, which prompted its promising applicability in cleaning emulsified wastewater.