| Autor: |
Li, Maijun, Long, Yubo, Zheng, Zhibo, Hu, Xu, Liu, Siwei, Chi, Zhenguo, Li, Nanwen, Xu, Jiarui, Zhang, Yi |
| Zdroj: |
Industrial & Engineering Chemistry Research; August 2024, Vol. 63 Issue: 32 p14240-14248, 9p |
| Abstrakt: |
Chemical modification of polyimide membranes is employed to achieve “trade-off” breakthrough or improve the plasticization resistance in CO2separation. However, harsh reaction conditions restrict the application of traditional chemical modifications. In this work, a simple chemical modification method─the coordination cross-linking between hydroxyl groups on polyimide (6FSPI) and Zn(II)─was investigated. Because of the reversible complexation of Zn(II) in the modified membrane as a transport carrier with CO2, and the addition of Zn(II) disrupts coiled chain of spiro moiety or intrachain cross-linking to induce more quantities of ultrafine micropores, the CO2permeability coefficient of the modified membrane is 2.97 times that of the pristine 6FSPI. Simultaneously, there is improvement in diffusion selectivity of the modified membrane, resulting in the CO2/CH4selectivity improvement. The overall CO2/CH4separation performance of the modified membrane reaches up to the 2008 Robeson limit. In addition to serving as facilitated transport carriers, Zn(II) can also be used as cross-linking points. The modified membrane maintains a stable CO2permeability coefficient beyond 4000 kPa. Our work suggests that the Zn(II) coordination cross-linking is a facile chemical modification method that can enhance long-term performance and separation performance of polyimide membranes simultaneously. |
| Databáze: |
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