Robust and stable superhydrophilic MIL-101 (Cr)-coated copper mesh for highly efficient oil/water emulsion separation.

In this study, dip coating method was investigated to prepare superhydrophilic MIL-101 (Cr)-coated copper mesh for highly efficient oil/water emulsion separation. To increase the surface area of synthesized MIL-101 (Cr), a purification procedure was developed to remove unreacted H2BDC crystals present in the channel of the initial MIL-101 (Cr) sample synthesized. After that, a dispersing solution of MIL-101 (Cr) was needed to coat on the copper mesh. Thermoplastic polyurethane (TPU) was used as a binder in this procedure. The prepared membranes of M1 (once coated mesh) to M6 (six times coated mesh) were performed to separate oil/water emulsion effectively. Contact angle tests showed the superhydrophilic/underwater superoleophobic wettability behavior of MIL-101 (Cr)-coated copper meshes. The wetting mechanism of the prepared membranes is mostly relevant to the surface functional groups of purified MIL-101 (Cr). Also, the roughness of the nanostructured coated membranes was improved because of the uniform coating of MIL-101 (Cr) which is integrated into hydrophilic TPU. Oil/water separation results showed that M2 (twice coated mesh) showed the maximum amount of water flux (83076 L m-2 h-1) in oil/water separation and M3 (three times coated mesh) had the best performance of oil/water emulsion with 99.99% separation efficiency.