Experimental and molecular simulation studies of CO2 adsorption on zeolitic imidazolate frameworks: ZIF-8 and amine-modified ZIF-8

• Published in: Adsorption : journal of the International Adsorption Society 2013-02, Vol.19 (1), p.25-37
• Main Authors: Liu, Defei, Wu, Yongbiao, Xia, Qibin, Li, Zhong, Xi, Hongxia
• Format: Article
• Language: English
• Subjects: Chemistry; Chemistry and Materials Science; Engineering Thermodynamics; Heat and Mass Transfer; Industrial Chemistry/Chemical Engineering; Surfaces and Interfaces; Thin Films
• ISSN: 0929-5607; 1572-8757
• DOI: 10.1007/s10450-012-9407-1

ZIF-8 has been rapidly developed as a potential candidate for CO 2 capture due to its low density, high surface area, and robust structure. Considering the electron-donating effect of amino functional groups, amino-modification is expected to be an efficient way to improve CO 2 adsorption of ZIF-8. In this work, grand canonical Monte Carlo (GCMC) simulation was performed to study the CO 2 adsorption isotherm based on ZIF-8, ZIF-8-NH 2 , and ZIF-8-(NH 2 ) 2 . ZIF-8 was synthesized and CO 2 adsorption isotherms based on ZIF-8 was measured. The experimental surface area, pore volume, and CO 2 adsorption isotherm were used to validate the force field. Adsorptive capacity of ZIF-8-NH 2 , and ZIF-8-(NH 2 ) 2 were first estimated. The GCMC simulation results indicated that the order of increasing CO 2 capacity of the ZIF-8 in the lower pressure regime is: ZIF-8 < ZIF-8-NH 2 < ZIF-8-(NH 2 ) 2 , and in the high pressure is: ZIF-8 < ZIF-8-(NH 2 ) 2 < ZIF-8-NH 2 . New adsorption sites can be generated with the existence of-NH 2 groups. In addition, for non-modified and amino-modified ZIF-8, it was the first time to use density functional theory (DFT) calculations to investigate their CO 2 adsorption sites and CO 2 binding energies. The present work indicates that appropriate amine-functionalized can directly enhanced CO 2 capacity of ZIF-8.