A thermally stable isoquinoline based ultra-microporous metal-organic framework for CH4 separation from coal mine methane

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2022-01, Vol.428, p.131136, Article 131136
• Main Authors: Qadir, Salman, Gu, Yiming, Ali, Sajjad, Li, Defu, Zhao, Shengsheng, Wang, Sheng, Xu, Hu, Wang, Shudong
• Format: Article
• Language: English
• Subjects: Coal mine methane; density functional theory (DFT); Metal–organic framework; Quinoline-5-carboxylic acid
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2021.131136

[Display omitted] •A novel quinolone-5-Carboxylic acid based MOF Ni-Qc-5 was successfully synthesized.•The adsorption isotherms of CH4 and N2 were obtained at 298 K and 1 bar.•CH4 and N2 adsorption binding sites were defined via DFT simulation.•The dynamic breakthrough experiments have performed to evaluate the separation performance. It is challenging for the recovery of methane from coal mine methane due to the involvement of air. Also, similar physical properties between methane and nitrogen increase the difficulty of methane separation. In this regard, a thermally stable microporous metal-organic framework was synthesized based on quinoline-5-carboxylic acid to enhance the separation of CH4 against N2. Its adsorption isotherms for CH4 and N2 were collected at 1 bar and 298 K. The highest adsorption CH4 uptake (1.3 mmol/g) was achieved as compared to N2 (0.28 mmol/g). Compared with other MOFs materials, Ni-Qc-5 possessed very low adsorption energy and high selectivity at low pressure 0.1 bar. Additionally, a density functional (DFT) simulation has been used to achieve a deep understanding of the adsorption binding sites. DFT results showed that CH4 have superior adsorption energy compared to N2. Moreover, dynamic breakthrough experiments were performed at different pressure over synthesized sample. The results showed that Ni-Qc-5 is the promising candidate for trapping of coal mine methane due to its outstanding regeneration and separation performance.