Fabrication of Janus cellulose nanocomposite membrane for various water/oil separation and selective one-way transmission

For satisfying various demands of water-oil emulsions separation, a Janus cellulose nanocomposite membrane has been fabricated in this study. Specifically, the cellulose paper with the superhydrophilic and underwater superoleophobic properties served as the substrate, meanwhile the PVDF/hydrophobic-SiO2 nanocomposite were successfully assembled to the top of substrate with the adhesion of PU by the technologies of high pressure spraying and electrostatic spinning for obtaining the superhydrophobic and superoleophilic layer. Under the action of gravity, Janus cellulose nanocomposite membrane effectively separated the water-in-oil emulsions when PVDF/hydrophobic-SiO2 nanocomposite layer (obverse) was on the top, and removed the small oil droplets from its oil-in-water emulsions when the cellulose layer (reverse) was on the top. Notably, the Janus cellulose nanocomposite membrane could complete the selective one-way transmission when the gravity effect was excluded. Moreover, the results of resistance against acid and base, abrasion resistance, filtration efficiency, repeatability, flux, etc. confirmed the remarkable superwetting durability and high selectivity of Janus cellulose nanocomposite membrane towards various emulsions, suggesting its enormous potential in practical water-oil separation.