Enhanced Thin-Film Composite Nanofiltration Membranes via Substrate Pore Structure Engineering: Performance and...

Area of Science:

• Materials Science
• Chemical Engineering
• Membrane Science

Background:

• Substrate pore size is crucial for polyamide thin-film composite (TFC) membrane structure and performance.
• The exact relationship and mechanism between substrate pore size and TFC membrane properties are not fully understood.

Purpose of the Study:

• To systematically investigate the influence of substrate pore size on TFC membrane selective layer, separation performance, and water transport kinetics.
• To elucidate the underlying mechanisms governing these effects.

Main Methods:

• Combined experimental investigations and molecular dynamics (MD) simulations.
• Fabrication and characterization of TFC membranes using substrates with varying pore sizes.
• Performance testing for water permeance and solute/solute selectivity.

Main Results:

• Larger substrate pore size resulted in a thinner, less cross-linked polyamide layer, yielding high water permeance (35.4 L m⁻² h⁻¹ bar⁻¹).
• Smaller substrate pore size led to a more uniform polyamide layer, enhancing solute/solute selectivity (erythromycin/NaCl = 426).
• MD simulations confirmed substrate pore size's significant impact on mass transfer.

Conclusions:

• Substrate pore size is a critical design parameter for TFC membranes.
• Optimizing substrate pore size enables targeted enhancement of both water permeance and selectivity.
• Provides a framework for designing high-performance TFC nanofiltration membranes.