不对称双层聚酰胺纳滤膜的制备及其性能研究

Preparation and performance study of asymmetric dual-layer polyamide nanofiltration membranes by one-step free interfacial polymerization

薄膜复合(TFC)纳滤膜作为一种新型膜分离技术,在水处理领域被人们广泛应用.减少聚酰胺层的厚度有利于增强TFC纳滤膜的渗透性.然而,具有超薄聚酰胺层的TFC纳滤膜的实际应用仍然面临巨大挑战.在此,我们提出了通过一步自由界面聚合法制备不对称双层聚酰胺纳滤膜的策略.所得不对称双层聚酰胺纳滤膜的上层聚酰胺层具有薄、光滑、致密的特点,相应的下层聚酰胺层则相对较厚、粗糙、疏松.薄而致密的上层聚酰胺层使得复合膜具有相对较高的透水率[185±10 L/(m^(2)·h·MPa)]和高截留率(Na_(2)SO_(4),97.2%±0.8%),较厚而疏松的下层聚酰胺层使得复合膜具有长时间运行稳定性.该研究为提高聚酰胺纳滤膜的分离性能提供了一种具有应用前景的制备方法.

Thin film composite(TFC)nanofiltration membranes are widely used in the field of water treatment as a new membrane separation technology.Reducing the thickness of the polyamide separation layer is beneficial for enhancing the permeability of TFC nanofiltration membranes.However,the practical application of TFC nanofiltration membranes with an ultra-thin polyamide layer still faces great challenges.Here,we propose a strategy for the preparation of asymmetric dual-layer polyamide nanofiltration membranes by one-step free interfacial polymerization.The resulting asymmetric dual-layer polyamide nanofiltration membranes have a thin,smooth and dense top polyamide separation layer,while the corresponding bottom polyamide separation layer is relatively thick,rough and sparse.The thin and dense top polyamide layer results in a relatively high water permeability[185±10 L/(m^(2)·h·MPa)]and high retention(Na_(2)SO_(4),97.2%±0.8%),while the thicker and looser bottom polyamide layer results in a long-term operational stability.This study provides a promising preparation strategy for improving the separation performance of polyamide composite membranes.