Secondary interfacial polymerization enables thermostable polyamide nanofiltration membranes for high-temperature...

Area of Science:

• Materials Science
• Chemical Engineering
• Separation Science

Background:

• Thin-film composite (TFC) nanofiltration (NF) membranes are crucial for separating ions and molecules.
• Traditional NF membranes lack structural stability at high temperatures, compromising separation efficiency.

Purpose of the Study:

• To develop a secondary interfacial polymerization strategy for fabricating NF membranes with enhanced thermal stability.
• To improve the structural integrity and performance of NF membranes under high-temperature conditions.

Main Methods:

• Fabrication of NF membranes using a secondary interfacial polymerization technique with conventional monomers.
• Characterization of the polyamide layer's thickness, charge, and compactness.
• Molecular dynamics simulations to assess polymer chain mobility.
• Performance evaluation of membrane rejections for MgSO₄ and Na₂SO₄ at 85°C.

Main Results:

• Secondary polymerization resulted in thicker, negatively charged polyamide layers.
• The process improved polyamide layer compactness and structural stability.
• Molecular dynamics simulations confirmed reduced polymer chain mobility.
• The modified NF membranes demonstrated high rejection rates for MgSO₄ and Na₂SO₄ at 85°C.
• Membranes exhibited excellent stability during temperature cycling and prolonged high-temperature operation.

Conclusions:

• The secondary interfacial polymerization strategy effectively enhances the thermal stability of TFC NF membranes.
• This method offers a promising approach for creating robust NF membranes for high-temperature separation applications.
• Simultaneous adjustment of chemical and physical structures via secondary polymerization is key to improved performance.