Raza Ayesha, Japip Susilo, Liang Can Zeng, Farrukh Sarah, Hussain Arshad, Chung Tai-Shung
Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore 117585, Singapore.
Department of Chemical and Materials Engineering, National University of Sciences and Technology, Islamabad 44000, Pakistan.
Polymers (Basel). 2021 Aug 31;13(17):2946. doi: 10.3390/polym13172946.
Currently, cellulose acetate (CA) membranes dominate membrane-based CO separation for natural gas purification due to their economical and green nature. However, their lower CO permeability and ease of plasticization are the drawbacks. To overcome these weaknesses, we have developed high-performance mixed matrix membranes (MMMs) consisting of cellulose triacetate (CTA), cellulose diacetate (CDA), and amine functionalized zeolitic imidazolate frameworks (NH-ZIF-8) for CO separation. The NH-ZIF-8 was chosen as a filler because (1) its pore size is between the kinetic diameters of CO and CH and (2) the NH groups attached on the surface of NH-ZIF-8 have good affinity with CO molecules. The incorporation of NH-ZIF-8 in the CTA/CDA blend matrix improved both the gas separation performance and plasticization resistance. The optimized membrane containing 15 wt.% of NH-ZIF-8 had a CO permeability of 11.33 Barrer at 35 °C under the trans-membrane pressure of 5 bar. This is 2-fold higher than the pristine membrane, while showing a superior CO/CH selectivity of 33. In addition, the former had 106% higher CO plasticization resistance of up to about 21 bar and an impressive mixed gas CO/CH selectivity of about 40. Therefore, the newly fabricated MMMs based on the CTA/CDA blend may have great potential for CO separation in the natural gas industry.
目前，醋酸纤维素（CA）膜因其经济环保的特性，在基于膜的天然气净化CO分离中占据主导地位。然而，其较低的CO渗透率和易塑化性是缺点。为克服这些弱点，我们开发了由三醋酸纤维素（CTA）、二醋酸纤维素（CDA）和胺官能化沸石咪唑框架（NH-ZIF-8）组成的高性能混合基质膜（MMM）用于CO分离。选择NH-ZIF-8作为填料是因为：（1）其孔径介于CO和CH的动力学直径之间；（2）附着在NH-ZIF-8表面的NH基团与CO分子具有良好的亲和力。在CTA/CDA共混基质中加入NH-ZIF-8，提高了气体分离性能和抗塑化性。含有15 wt.% NH-ZIF-8的优化膜在35℃、跨膜压力5 bar下的CO渗透率为11.33 Barrer。这比原始膜高2倍，同时显示出33的优异CO/CH选择性。此外，前者的CO抗塑化性提高了106%，高达约21 bar，混合气体CO/CH选择性约为40，令人印象深刻。因此，新制备的基于CTA/CDA共混物的MMM在天然气工业中进行CO分离可能具有巨大潜力。
