Bioinspired photo-responsive membrane enhanced with "light-cleaning" feature for controlled molecule release

Area of Science:

• Materials Science
• Polymer Chemistry
• Environmental Engineering

Background:

• Membrane fouling is a significant challenge in water treatment, reducing efficiency and increasing operational costs.
• Existing methods for fouling removal are often inefficient and can damage membrane structures.
• Controlling molecule release from membranes is crucial for applications like drug delivery and separation.

Purpose of the Study:

• To develop novel photo-responsive membranes (PRMs) mimicking plant stomata for enhanced fouling removal and controlled molecule release.
• To investigate the effect of azobenzene content on PRM properties and performance.
• To demonstrate the light-triggered control over pore size, hydrophilicity, and molecule release.

Main Methods:

• Synthesized photo-responsive polymers by grafting azobenzene onto PMAA chains, which were further grafted from P(VDF-CTFE).
• Fabricated high-flux PRMs using a non-solvent-induced phase-inversion method with varying azobenzene content.
• Evaluated membrane performance by measuring pore size, surface hydrophilicity, backflushing efficiency, and fouling removal using BSA and E. coli.

Main Results:

• PRMs exhibited reversible changes in pore size and surface hydrophilicity upon switching between visible light and UV irradiation.
• The light-cleaning process recovered over 90% of irreversible flux decline caused by organic and biological foulants.
• Higher azobenzene content led to more pronounced light-induced property changes but smaller absolute pore sizes.
• PRMs demonstrated light-triggered controlled release of molecules based on their size.

Conclusions:

• The developed PRMs offer an efficient solution for mitigating irreversible membrane fouling.
• The light-triggered molecule release capability expands the potential applications of these novel membranes.
• This technology holds promise for improving membrane performance in various separation and purification processes.