Electrostatic
Assembly of a Titanium Dioxide@Hydrophilic
Poly(phenylene sulfide) Porous Membrane with Enhanced Wetting Selectivity
for Separation of Strongly Corrosive Oil–Water Emulsions
The
efficient treatment of oil–water emulsions in extreme
environments, such as strongly acidic and alkaline media, remains
a widespread concern. Poly(phenylene sulfide) (PPS)-based porous membranes
with excellent resistance to chemicals and solvents are promising
for settling this challenge. However, the limited hydrophilicity and
the poor hydrated ability of the hydrophilic PPS (h-PPS) membranes
reported in the literature prevents them from separating oil–water
emulsions with high efficiency, large fluxes, and good antifouling
performances. In this study, a firm rough TiO2 layer is
constructed on a h-PPS membrane via electrostatic assembly to improve
the surface hydrophilization. The introduction of the TiO2 layer increases the wetting selectivity and decreases the oil adhesion,
which makes it capable to efficiently treat oil-in-water emulsions
(efficiency > 98%). Most importantly, the underwater critical oil
intrusion pressure almost doubled after the incorporation of the TiO2 layer, which allows the membrane to withstand pressurized
filtration, achieving a high flux of ∼4000 L m–2 h–1. This is more than 2 orders of magnitude larger
than the flux of the reported h-PPS. Furthermore, the TiO2@h-PPS membrane displays long-term stability in separating oil–water
emulsions in strong acid and strong alkali, showing a promising prospect
for the treatment of strongly corrosive emulsions.