Rational Design of High-Flux, Eco-Friendly, and Versatile Superhydrophobic/Superoleophilic PDMS@ZIF-7/Cu₃(PO₄)₂ Mesh with Self-Cleaning Property for Oil–Water Mixture and Emulsion Separation

Abstract

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 3 (PO 4 ) 2 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 3 (PO 4 ) 2 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 −2 h −1 ), and preferred self-cleaning property were thus achieved by such manipulation of the copper mesh. The PDMS@ZIF-7/Cu 3 (PO 4 ) 2 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.

Three in One: Superoleophilic, Chemically and Mechanically Resistant ZIF-7 and ZIF-11 Percolation Networks for Selective Permeation of Oils and Chlorinated Solvents

“…The N 1s spectrum showed peaks of N–C and N–Zn corresponding to BIM coordinated to zinc (Figure c,g). The high-resolution spectra of Zn 2p displayed well-defined positions of Zn 2p 1/2 and Zn 2p 3/2 , which are typically observed for ZIF nanostructures (Figure d,h). ,, The oxygen bonding contribution originating from O–C and hydroxyl group linked to the fluorinated graphene lattice could be observed (Figure S3b,d), and the sizable contribution of oxygen could be attributed to the sample preparation, particularly in the powdered form of graphene nanoplatelets …”

“…The high-resolution spectra of Zn 2p displayed well-defined positions of Zn 2p 1/2 and Zn 2p 3/2 , which are typically observed for ZIF nanostructures (Figure 1d,h). 32,46,47 The oxygen bonding contribution originating from O−C and hydroxyl group linked to the fluorinated graphene lattice could be observed (Figure S3b,d), and the sizable contribution of oxygen could be attributed to the sample preparation, particularly in the powdered form of graphene nanoplatelets. 48 The morphologies of pure ZIF-7 and ZIF-11 and of FG-ZIF-7 and FG-ZIF-11 were evaluated by scanning electron microscopy (SEM) characterization (Figures 1i,k and S4).…”

“…Particularly, oil–water separations demand stringent stability under aqueous and corrosive environments, which lead to degradation of the sorbent impacting the selective sorption ability. Xu et al reported copper mesh coated with PDMS@ZIF-7/Cu 3 (PO 4 ) 2 displaying superhydrophobic (155°)–superoleophilic properties for the gravity-driven separation of oil and emulsions from water mixtures . Nevertheless, a generic route toward improved chemical stability of ZIF-7 and ZIF-11 is required using robust templates and simple routes, besides exploiting the binding abilities of ZIFs toward various substrates yielding superwetting macrostructures.…”

Nanoengineering Metal–Organic Frameworks and Derivatives for Electrosynthesis of Ammonia

“…By judicious selection of the building blocks and appropriate reaction conditions, it is possible to achieve rational design and engineering of the frameworks. Owing to their controllable morphology, high surface area, designable porosity, tunable pore size, and flexible electronic structure, MOFs have not only exhibited extraordinary performance in gas storage and separation [ 10 , 11 ], energy storage [ 12 – 16 ], microwave adsorption [ 17 – 19 ], sensors [ 20 , 21 ] and magnetic and molecular recognition [ 22 ] but have also received extensive attention to directly activate and convert kinetically inert, simple molecules [ 23 , 24 ] over the last few years. In addition to their direct use as electrocatalysts, hybrid supports, or functional tuners, MOF materials can also be used as electrocatalyst precursors or templates for further fabrication of conductive and stable nanoporous carbon materials (NPC) [ 25 ].…”

Preparation of Superhydrophobic Surfaces Based on Copper Mesh Substrates and Its Application Performance

“…There are two main traditional ways to obtain superhydrophobic surfaces: increasing surface roughness and decreasing surface energy . According to these two principles, the main methods to prepare superhydrophobic surfaces are etching, , hydrothermal, anodization, electrochemical deposition, − milling method, sol–gel method, and in situ growth. , However, there are many methods proposed in the research with complicated steps and experimental setups, such as ultrasonic etching technique to obtain copper mesh surfaces with parabolic-like rough structure by Qiao et al, or limited by certain substrates and expensive raw materials, such as the sol–gel method for polyethylene glycol ethylene terephthalate (PET) filters using ethyl orthosilicate (TEOS) as the precursor and perfluorodecyltriethoxysilane (PFDTES) as the modifier adopted by Dong et al Yuan et al used the backside of a fresh bamboo leaf as the original template, and by combining the template on a copper foil, a regular multiscale layered structure was prepared on the copper foil; after further treatment with stearic acid, the sample had superhydrophobic properties with a WCA of 160°. However, the corrosion resistance of this sample was not tested.…”