On the Disproportionate Contribution of Membrane Electron Donor Functionality in Membrane Biofouling

Area of Science:

• Surface chemistry
• Materials science
• Environmental engineering

Background:

• Membrane fouling is a major challenge in water treatment, impacting efficiency and lifespan.
• Understanding interfacial properties is crucial for mitigating organic and biofouling.
• Existing models often overlook the specific contributions of electron donicity and accepticity.

Purpose of the Study:

• To identify the critical interfacial properties influencing membrane organic fouling and biofouling.
• To investigate the role of Lifshitz-van der Waals (LW) and Lewis acid-base (AB) surface tensions in fouling.
• To establish a predictive relationship between membrane surface properties and fouling resistance.

Main Methods:

• Systematic characterization of LW and AB surface tensions for membranes and biofoulants.
• Theoretical analysis of interfacial free energy of adhesion (ΔG132) using modified equations.
• Experimental validation through static bacterial adhesion, alginic acid filtration, and wastewater filtration tests.

Main Results:

• Membrane electron donicity emerged as the dominant factor in governing interfacial adhesion energy.
• Higher membrane electron density correlated strongly with reduced microbial adhesion and alginate fouling.
• Experimental fouling propensities aligned with theoretical predictions based on surface electron density.

Conclusions:

• Surface electron donicity is a critical parameter for predicting and controlling membrane fouling.
• Optimizing membrane materials for enhanced electron donicity can significantly improve fouling resistance.
• This study provides a theoretical and experimental framework for designing anti-fouling membranes.