Microfiltration Membrane Pore Functionalization with Primary and Quaternary Amines for PFAS Remediation: Capture,...

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Global water supplies are increasingly contaminated with per- and polyfluoroalkyl substances (PFAS) due to widespread industrial use.
• Conventional wastewater treatment methods produce concentrated waste streams that pose environmental challenges.
• There is a need for advanced treatment solutions to effectively remove and manage PFAS contaminants.

Purpose of the Study:

• To develop and evaluate a selective anion-exchange membrane for capturing and concentrating PFAS from aqueous streams.
• To investigate the performance of functionalized microfiltration membranes for PFAS removal.
• To assess the reusability and efficiency of the developed membrane technology.

Main Methods:

• Commercial microfiltration membranes were modified via pore functionalization with primary and quaternary amine-containing polymer networks.
• Membrane loading was quantified for both functionalization types (0.22-0.85 mmol/g for quaternary, 0.97-3.4 mmol/g for primary).
• PFAS removal efficiency was tested using perfluorooctanoic acid (long-chain) and perfluorobutyric acid (short-chain) with analysis of water permeance and rejection rates.

Main Results:

• Modified membranes showed water permeances between 45-131 LMH/bar.
• High rejection rates were achieved: up to 90% for perfluorooctanoic acid and 50-80% for perfluorobutyric acid after 30% permeate recovery.
• Regenerated membranes maintained capture performance over three operational cycles, demonstrating reusability.

Conclusions:

• Functionalized anion-exchange membranes offer a promising approach for selective PFAS capture and concentration from water.
• The developed membrane platform is versatile and can be adapted for various applications to improve water safety.
• Optimizing capture efficiency involves considering charge density, water flux, and contaminant concentration for enhanced water treatment.