Molecular simulation on the stability and adsorption properties of choline-based ionic liquids/IRMOF-1 hybrid composite for selective H2S/CO2 capture

• Published in: Journal of hazardous materials Vol. 399; p. 123008
• Main Authors: Ishak, Mohd Adil Iman, Jumbri, Khairulazhar, Daud, Shaari, Abdul Rahman, Mohd Basyaruddin, Abdul Wahab, Roswanira, Yamagishi, Hiroshi, Yamamoto, Yohei
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.11.2020
• Subjects: Enthalpy; Entropy; Free energy; Hybrid material; IL loading ratio; Entropy; IL loading ratio; Hybrid material; Enthalpy; Free energy
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2020.123008

[Display omitted] •Compatibility and adsorption of IL/IRMOF-1 was predicted using simulation.•IL/IRMOF-1 shows an improved resistance to water compared to pristine IRMOF-1.•Adsorption of H2S and CO2 was highly dependent on the IL loadings.•The hybrid composite was more selective in capturing H2S than CO2. The compatibility and performance of an Isoreticular Metal-Organic Frameworks (IRMOF-1) impregnated with choline-based ionic liquids (ILs) for selective adsorption of H2S/CO2, were studied by molecular dynamics (MD) simulation. Cholinium alanate ([Chl][Ala]) was nominated as the suitable IL for impregnation into IRMOF-1, consistent with the low RMSD values (0.546 nm, 0.670 nm, 0.776 nm) at three IL/IRMOF-1 w/w ratios (WIL/IRMOF-1 = 0.4, 0.8, and 1.2). The [Chl]+ and [Ala]− ion pair was located preferentially around the carboxylate group within the IRMOF-1 framework, with the latter interacting strongly with the host than the [Chl]+. Results of radius of gyration (Rg) and root mean square displacement (RMSD) revealed that a ratio of 0.4 w/w of IL/IRMOF-1 (Rg = 1.405 nm; RMSD = 0.546 nm) gave the best conformation to afford an exceptionally stable IL/IRMOF-1 composite. It was discovered that the IL/IRMOF-1 composite was more effective in capturing H2S and CO2 compared to pristine IRMOF-1. The gases adsorbed in higher quantities in the IL/IRMOF-1 composite phase compared to the bulk phase, with a preferential adsorption for H2S, as shown by the uppermost values of adsorption (AH2S = 17.954 mol L−1 bar-1) and an adsorption selectivity (ASH2S/CO2 = 43.159) at 35 IL loading.