Smart Fiber Membrane for pH-Induced Oil/Water Separation

Area of Science:

• Materials Science
• Polymer Chemistry
• Environmental Engineering

Background:

• Wastewater contamination by oil and organic compounds presents significant environmental and human health risks.
• Effective oil-water separation technologies are crucial but remain challenging to implement efficiently.
• Developing advanced materials with tunable properties is key to addressing these separation challenges.

Purpose of the Study:

• To fabricate a smart fiber membrane with switchable surface wettability for oil-water separation.
• To synthesize a pH-responsive copolymer precursor for membrane fabrication.
• To demonstrate the membrane's efficiency and reusability in gravity-driven separation processes.

Main Methods:

• Electrospinning of poly(methyl methacrylate)-block-poly(4-vinylpyridine) (PMMA-b-P4VP) copolymer fibers onto a stainless steel mesh.
• Synthesis of the cost-effective PMMA-b-P4VP precursor via copper(0)-mediated reversible-deactivation radical polymerization.
• Investigation of the membrane's switchable surface wettability and oil-water separation performance under varying pH conditions.

Main Results:

• The fabricated fiber membrane exhibited switchable surface wettability due to the pH-responsive P4VP and oleophilic/hydrophilic PMMA components.
• Efficient gravity-driven separation of oil and water was achieved, with selective oil passage under neutral/alkaline conditions and reversed separation in acidic conditions (pH 3).
• The membrane demonstrated high separation efficiency and stable, switchable wettability over numerous separation cycles, alongside excellent oil-fouling repellency.

Conclusions:

• A cost-effective, easily mass-producible smart fiber membrane with switchable wettability has been successfully developed.
• The membrane shows significant potential for practical applications in water purification and oil recovery due to its efficient and controllable oil-water separation capabilities.
• The unique 3D fiber network structure enhances oil-water wetting properties, contributing to the membrane's overall performance.