Mixed matrix membranes comprising dual-facilitated bio-inspired filler for enhancing CO2 separation

• Published in: Separation and purification technology Vol. 276; p. 119347
• Main Authors: Lv, Xia, Huang, Lu, Ding, Siyuan, Wang, Jiangnan, Li, Long, Liang, Chao, Li, Xueqin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2021
• Subjects: Bio-inspired material; CO2 separation; Facilitated transport; Mixed matrix membrane; Pebax; Mixed matrix membrane; Pebax; Bio-inspired material; CO2 separation; Facilitated transport
• ISSN: 1383-5866
• DOI: 10.1016/j.seppur.2021.119347

[Display omitted] •A dual-facilitated biomimetic zeolitic imidazolate framework (Bio-ZIF) was designed.•Biomimetic active sites and amino groups played dual-facilitated functions in MMMs.•Dual-facilitated functions facilitated quickly CO2 transport in MMMs.•The resulting MMMs exhibit superior CO2/CH4 separation performance. In this work, a novel dual-facilitated bio-inspired zeolitic imidazolate framework (Bio-ZIF) was proposed to simulate the structure and function of carbonic anhydrase (CA), because it can overcome the low stability and high price of the CA. A novel type of mixed matrix membrane (MMM)-composed of Bio-ZIF and Pebax® MH 1657 (Pebax) was fabricated and used to enhance CO2 separation performance. The bio-inspired active sites of Bio-ZIF can catalyze the reversible hydration of CO2 in the form of bicarbonate to facilitate the quick transport of CO2 across the MMMs, increasing CO2 permeability. Furthermore, the amino groups of Bio-ZIF reacted with CO2 to produce zwitterion as an intermediate during the reversible reaction, facilitating CO2 permeation in the MMMs. It can be concluded that Bio-ZIF performed the dual-facilitated functions in the MMMs by reversible hydration and reversible reaction with CO2 molecules. Thus, the as-prepared MMMs exhibited an excellent CO2 separation performance. Particularly, Pebax/Bio-ZIF-12 MMM presented an optimal CO2 permselectivity with CO2 permeability of 542 ± 6.0 Barrer and CO2/CH4 separation factor of 40 ± 0.4, surpassing the 2008 upper bound. This work provided an ingenious strategy to design bio-inspired fillers to achieve dual-facilitated functions in MMMs for enhancing CO2 separation.