Abstract:

As a potential separation material, metal-organic frameworks (MOFs) have its unique pore structure, high adaptability and selectivity, and have a broad application prospect in the field of membrane separation. However, MOFs are vulnerable to damage in humid environments, which severely limits their application in membrane separation. Therefore, improving the water stability of MOFs is one of the important problems in realizing its application in the field of membrane separation. In this paper, Cu-BTC-AC filler with high water stability was prepared by the functionalization of ammonium citrate and MMMs with different filler content were prepared by embedding the obtained Cu-BTC-AC in Pebax 1657 matrix. The CO₂/N₂ separation performance of the Cu-BTC-AC/Pebax MMMs at 25℃ under humid condition was examined. Compared with the pure Pebax membrane, the prepared MMMs show improved CO₂ permeability and CO₂/N₂ selectivity, with an optimized CO₂ permeance of 776.5 GPU accompanied by the CO₂/N₂ selectivity of 46.7. Besides, the high water stability of the filler originated from AC functionalization endows the prepared MMMs with potential for application in practical industrial gas separations.

Key words: metal-organic framework, ammonium citrate, water-stability, mixed-matrix membrane, gas separation

摘要：

金属-有机骨架材料（metal-organic frameworks，MOFs）作为一种有潜力的分离材料，其孔道结构独特，具有高度可调性和选择性，在膜分离领域具有广阔的应用前景。然而，MOFs在潮湿的环境下易损坏，这严重限制了其在膜分离领域的应用。因此，提高MOFs的水稳定性，是实现其在膜分离领域应用的重要问题之一。本文通过柠檬酸铵（ammonium citrate，AC）功能化制备了具有高水稳定性的Cu-BTC-AC填料，并将其与Pebax 1657聚合物共混制备了系列不同掺杂量的MMMs，并考察了25℃饱和水蒸气下所制备Cu-BTC-AC/Pebax膜的CO₂/N₂分离性能。与纯Pebax膜相比，本工作中制备的MMMs具有更优异的CO₂渗透性和CO₂/N₂选择性，在CO₂渗透通量为776.5GPU时CO₂/N₂选择性为46.7。此外，AC功能化改性赋予填料的高水稳定性使得本工作中制备的MMMs具备了应用于实际工业气体分离的潜力。

关键词: 金属有机骨架, 柠檬酸铵, 水稳定性, 混合基质膜, 气体分离