一种MOF基混合基质膜的制备及其纳滤性能

Preparation of a MOF-based Mixed Matrix Membrane and Its Nanofiltration Performance

对商业化的聚丙烯腈(PAN)进行预处理改性得到基底---预处理后的聚丙烯腈(HPAN),并将研磨后的金属有机框架(metal-organic framework,MOF)材料PCN-250作为填充物与聚乙烯亚胺(PEI)共混后旋涂在HPAN基底上,得到了一种可用于纳滤的PCN-250/PEI-HPAN混合基质膜。对MOF和制备后的混合基质膜的表征显示研磨后的PCN-250在水中具有较好的分散性,并且随着膜制备过程中PCN-250使用量的增加,膜表面的粗糙度增大,膜的有效面积相应增加。由于PCN-250晶粒表面带有负电荷,它的加入使膜表面整体上电负性更高,更有利于负电荷型染料分子的截留。通过SEM和AFM表征了膜的形貌结构,并研究了MOF的不同负载率和PEI质量浓度对膜性能的影响。结果表明,PCN-250负载率为75%时,膜的纳滤性能最优,对水的渗透率可达1480 L/(m^(2)·h·MPa),对染料分子甲基蓝的截留率为97.3%。

A commercial polyacrylonitrile(PAN)was pretreated and modified to obtain the substrate HPAN,and a ground MOF material PCN-250 as filler was blended with polyethyleneimide(PEI)and spin-coated on the HPAN substrate to obtain a PCN-250/PEI-HPAN mixed matrix membrane for nanofiltration.The characterization of MOF and the prepared mixed matrix membrane showed that the ground PCN-250 had good dispersion in water,and with the increase of the amount of PCN-250 used in the membrane preparation process,the roughness of the membrane surface and the effective area increased accordingly.Since the grain surface of PCN-250 was negatively charged,the addition of PCN-250 into polymer matrix resulted in high negative charge on the membrane surface,which improved its performance in the rejection of anionic dyes.We also characterized the membrane by SEM and AFM and optimized the membrane preparation procedure.Results show that when the loading of PCN-250 was 75%,the nanofiltration performance of the PCN-250/PEI-HPAN membrane pair was the highest,with water permeability of 1480 L/(m^(2)·h·MPa),and a rejection of 97.3%to the dye methyl blue.