Sub-10 nm Polyamide Nanofiltration Membrane for Molecular Separation

Area of Science:

• Materials Science
• Chemical Engineering
• Separation Science

Background:

• Membrane processes offer energy-efficient alternatives to thermal separation for small molecule purification.
• Achieving high permeability and selectivity in membranes is crucial for effective separation.

Purpose of the Study:

• To synthesize sub-10 nm thick polyamide nanofiltration membranes with enhanced performance.
• To explore a novel interfacial polymerization method for creating ultrathin membranes.

Main Methods:

• Interfacial polymerization of ethidium bromide (EtBr) and trimesoyl chloride (TMC) in a water-hexane system.
• Characterization of membrane thickness, water permeation, and Congo red rejection.

Main Results:

• Successfully synthesized ultrathin polyamide membranes with thickness below 10 nm.
• Achieved ultrafast water permeation of 40 L m⁻² h⁻¹ bar⁻¹.
• Demonstrated high Congo red rejection rate of 93%.

Conclusions:

• The developed method enables the synthesis of ultrathin polyamide membranes via interfacial polymerization.
• These membranes show significant potential for energy-efficient separation processes.
• The low solubility of EtBr monomer is key to controlling membrane thickness.