Emulsion

Engineering

Biofouling

Materials science

Coating

Fouling

Biochemistry

Chemical engineering

Polymer

Nanotechnology

Membrane

Composite material

Membrane fouling

Chemistry

Polyvinylidene fluoride

Microfiltration

Permeation

Hydrophilization

Separation and Purification Technology

Membrane fouling is one of the difficult challenges that restrict the efficient application of membrane separation technology in oil/water separations. Hydrogel with strong hydration capability has been considered as an ideal material for preparing anti-oil-fouling coating for membranes. Although some hydrogel-based coatings have been developed for the membrane interface hydrophilization modification, controlling the morphology of gel layers and improving the flux of hydrogel coated membranes remains a difficult matter to resolve. In this study, we elegantly designed a new mineral-hydrogel coating with nanostructures to modify hydrophobic polyvinylidene fluoride (PVDF) microfiltration membranes by an alternate quaternary soaking strategy. Compared with the merely hydrogel-coated membrane, the pure water flux of novel mineral-hydrogel coating membrane increased by 214% and the permeation increased by 127% with the oil rejection rate of 99.6% at 0.4 bar. Most importantly, the newly-built mineral-hydrogel layer on porous support possessed excellent hydrophilicity, underwater super-oleophobic properties and superior anti-oil-fouling performance, which is greatly promising in oily sewage remediation. In addition, this mineral-hydrogel coating could also be constructed on other hydrophobic substrates successfully, such as commercial melamine resin. Our facile strategy for designing and constructing synergetic mineral-hydrogel architecture may also inspire other functional coatings with nanostructures.

Bio-inspired mineral-hydrogel hybrid coating on hydrophobic PVDF membrane boosting oil/water emulsion separation