Electrophoretic nuclei assembly of MOFs in polyamide membranes for enhanced nanofiltration
Electrophoretic nuclei assembly of MOFs in polyamide membranes for enhanced nanofiltration
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用于增强纳滤的聚酰胺膜中 MOF 的电泳核组装
DOI：
10.1016/j.desal.2021.115125
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发表时间：
2021-05-06
期刊：
影响因子：
9.9
通讯作者：
Lin, Jiuyang
中科院分区：
文献类型：
--
作者：
Li, Jian;Liu, Riri;Lin, Jiuyang
薄膜纳米复合（TFN）聚酰胺（PA）膜由于其顶层的物理化学性质得到改善从而具有多种分离性能，因此受到了越来越多的关注。然而，常用的制备方法因无法控制纳米填料的负载量，导致纳米填料在PA层中随机且分布不充分，并产生界面缺陷，从而使膜性能下降。在此，提出了一种通过电泳沉积（EPD）将金属 - 有机框架（即ZIF - 8）引入PA层的合理策略。在外部直流电场的驱动下，ZIF - 8纳米颗粒均匀地组装在多孔超滤（UF）基底上，通过真空辅助界面聚合（IP）制备高性能TFN纳滤膜。由于引入了ZIF - 8纳米颗粒，其为水的快速渗透创造了额外的纳米通道，所得到的TFN纳滤膜的水渗透率提高到22.4±1.2 L·m⁻²·h⁻¹·bar⁻¹。此外，这种EPD工艺有效地调整了膜表面性质（例如，ζ电位），对硫酸钠（96.9±0.7%）具有相当高的截留率，但对氯化钠（18.9±2.5%）的截留率较低，表明在硫酸根离子和氯离子之间具有优异的选择性。这项研究强调了EPD工艺在精确锚定纳米材料以设计用于目标分离的高性能TFN纳滤膜方面的显著功效。
Thin film nanocomposite (TFN) polyamide (PA) membranes has drawn increasing attention due to the improved physicochemical properties of the top layer for versatile separation performance. However, the commonly used fabrication approach, lacking a controllable loading of nanofillers, leads to a random and insufficient distribution of nanofillers into the PA layer and generates interfacial defects that deteriorate the membrane performance. Herein, a rational strategy for incorporating metal-organic frameworks (i.e., ZIF-8) into the PA layer via electrophoretic deposition (EPD) was proposed. Driven by an external direct current field, the ZIF-8 nanoparticles were uniformly assembled onto a porous ultrafiltration (UF) substrate for fabrication of high-performance TFN nanofiltration membranes by vacuum-assisted interfacial polymerization (IP). The resultant TFN nanofiltration membrane yielded an enhanced water permeability of 22.4 +/- 1.2 L center dot m- 2 center dot h-1 center dot bar- 1, due to incorporation of ZIF-8 nanoparticles which created extra nano-channels for fast water permeation. Additionally, such an EPD process effectively tailored the membrane surface properties (e.g., zeta potential) and conferred a considerably high rejection for Na2SO4 (96.9 +/- 0.7%) but a low rejection for NaCl (18.9 +/- 2.5%), demonstrating an excellent selectivity between SO42- and Cl- ions. This study highlights the impressive efficacy of the EPD process in precisely anchoring nanomaterials to design high-performance TFN nanofiltration membranes for target separations.