Omniphobic Polymer/Graphene Oxide-Coated PVDF Membrane for Stable Membrane Distillation in Surfactant-Containing...

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Graphene oxide (GO) coatings enhance membrane distillation (MD) stability against organic contaminants.
• GO's hydrophilicity necessitates complex functionalization for anti-wetting properties, hindering scalability.
• Scalable anti-fouling solutions are crucial for effective water remediation.

Purpose of the Study:

• To develop a scalable, omniphobic coating for MD membranes using GO and perfluoropolyether (PFPE).
• To improve the anti-wetting and anti-fouling performance of commercial PVDF membranes.
• To demonstrate a generalizable strategy for creating robust, anti-fouling surfaces for water treatment.

Main Methods:

• Sequential slot-die coating of GO followed by PFPE dip-coating on PVDF membranes.
• Utilizing a volatile solvent for self-limited, conformal PFPE deposition on GO.
• Fabricating omniphobic polymer-graphene oxide (OGO) coatings.

Main Results:

• OGO membranes exhibited >99.7% NaCl rejection and >15 LMH water flux in direct contact MD.
• The coating maintained performance during long-term operation with low-surface-tension feeds and surfactants.
• The PFPE layer suppressed wetting while preserving vapor-selective pathways with minimal resistance.

Conclusions:

• The scalable GO-PFPE coating method avoids complex GO modification.
• This approach offers a generalizable strategy for creating anti-wetting, anti-fouling surfaces.
• The OGO coating shows significant promise for advancing water remediation technologies.