Engineering Polyamide Networks via Synergistic Surfactant Regulation and Solvent Treatment for Efficient Ion
Wan-Ting Lin1, Xiaohong Chen1,2, Xiao-Wei Luo1
1MOE Key Laboratory of Macromolecular Synthesis and Functionalization, MOE Engineering Research Center of Membrane and Water Treatment Technology, Zhejiang Key Laboratory of Advanced Organic Materials and Technologies, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310058, P. R. China.
ACS Applied Materials & Interfaces
|July 27, 2026
Summary
A new solvent treatment refines nanofiltration membranes for better ion separation. This method improves selectivity for monovalent ions over divalent ions, crucial for resource recovery.
Area of Science:
- Materials Science
- Chemical Engineering
- Environmental Science
Background:
- Separating monovalent and divalent ions is critical for resource recovery but challenging for current nanofiltration membranes.
- Classic poly(piperazine-amide) membranes struggle with cation separation due to surface charge and pore size limitations.
Purpose of the Study:
- To develop an optimized nanofiltration membrane for efficient separation of monovalent and divalent ions.
- To address limitations in cation separation by refining polyamide network architecture and surface properties.
Main Methods:
- Utilized surfactant-assisted interfacial polymerization to create polyamide networks.
- Applied a novel solvent treatment to refine the polymer network, removing oligomers and thinning the selective layer.
- Characterized the optimized membrane's surface charge, pore size distribution, and separation performance.
Main Results:
- The optimized membrane exhibited an attenuated negative surface charge and a more uniform pore size distribution.
- Achieved high selectivity for monovalent over divalent ions (Li+/Mg2+ selectivity of 96.1; Cl-/SO42- selectivity of 1351).
- Demonstrated high water permeance (14.9 L m-2 h-1 bar-1).
Conclusions:
- Solvent treatment is an effective strategy to optimize polyamide nanofiltration membranes.
- The refined membranes show enhanced performance for efficient monovalent/divalent ion separation.
- This approach offers a straightforward method for improving ion separation in resource recovery applications.
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