Electrostatic Assembly of a Titanium Dioxide@Hydrophilic Poly(phenylene sulfide) Porous Membrane with Enhanced Wetting Selectivity for Separation of Strongly Corrosive Oil–Water Emulsions

Abstract

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.

Superwetting Oil/Water Separation Membrane Constructed from In Situ Assembled Metal–Phenolic Networks and Metal–Organic Frameworks

“…It was believed that the hydrophilic hierarchical characteristic of the TTN−ZIF−TTN hybrid layer could fasten the hydration layer at the membrane/ water interface and thus induced an oil defense barrier on the membrane surface. 32 3.3. Permeation and Emulsion Separation Performance of the TTN−ZIF−TTN@PVDF Membrane.…”

“…The easy detachment of oil droplets from the membrane surface further confirmed the low-oil-adhesion potential of the TTN–ZIF–TTN@PVDF membrane. It was believed that the hydrophilic hierarchical characteristic of the TTN–ZIF–TTN hybrid layer could fasten the hydration layer at the membrane/water interface and thus induced an oil defense barrier on the membrane surface …”

“…The rational design and facile construction of both the hydrophilic composition and hierarchical topography of membranes can be readily achieved. The hydrophilic functionalization of membranes can occur either by directly decorating or by in situ synthesizing hydrophilic polymers and inorganics on the surfaces and thus give rise to the exceptional water-binding affinity. − Remarkably, phenolic adhesive coatings inspired from mussel adhesion become fascinating and progressive candidates, allowing the effective, straightforward, and versatile engineering of surface hydrophilicity. − The hierarchical structures of membranes can be constructed by directly anchoring or by in situ generating nanomaterials with specific nanoarchitectures on micro-structured membrane substrates. − With the vigorous development of metal–organic frameworks (MOFs) greatly enriching the diversity of nanomaterials, MOF nanocrystals provide excellent alternatives for hierarchical engineering with specifically manipulated dispersion or orientation. − Noteworthily, the advances of the phenolic-based hydrophilic engineering strategies and MOF-based hierarchical engineering strategies share common research focuses on metal–organic coordination chemistry. Metal–phenolic networks (MPNs) and MOFs are the most famous and prominent members of metal–organic coordination materials .…”

Evaluation of polyphenylene sulfide by surface thermodynamics approaches: Comparison with common polymers

“…11 In a similar approach, Han et al prepared a PPS based membrane by eliminating the limited hydrophilicity of the PPS and increasing wetting selectivity at the same time. 12 All of these studies show that PPS is a promising polymer that can be used in much more applications in the future, and the proper determination of the wetting characteristics and SFE components of PPS is critical. However, a detailed SFE analysis for PPS does not seem to be available in the literature.…”

In-situ self-dissolving and regenerating synthesis of superwetting cotton fabric with excellent oil/water emulsions separation performance

“…The hydrophilic decorating of the membrane can be achieved either by direct modi cation or by in-situ synthesis of hydrophilic polymers or inorganic substances on the membrane surface. [18][19] Cellulose, the most abundant natural polysaccharide, has strong a nity to cellulosic surfaces, inherent surface hydrophilicity, and reactive surface arising from abundant hydroxyl groups as functional coating materials. [20] Noteworthy, the advances of the cellulose-based hydrophilic and hierarchical engineering strategies can be achieved through in-situ dissolution and regeneration process of natural cellulose-based substrates.…”