Ionic Liquid/Metal–Organic Framework Composite for CO₂ Capture: A Computational Investigation

Abstract

A composite of ionic liquid [BMIM][PF6] supported on metal–organic framework IRMOF-1 is investigated for CO2 capture by molecular computation. Due to the confinement effect, IL in the composite exhibits an ordered structure as observed from radial distribution functions. The bulky [BMIM]+ cation resides in the open pore of IRMOF-1, whereas the small [PF6]− anion prefers to locate in the metal cluster corner and possesses a strong interaction with the framework. [BMIM]+ exhibits a greater mobility than [PF6]−, which is also observed in simulation and experimental studies for imidazolium-based ILs in the bulk phase. With increasing IL ratio in the composite and thus enhancing confinement effect, the mobility of [BMIM]+ and [PF6]− is reduced. Ions in the composite interact strongly with CO2; in particular, the [PF6]− anion is the most favorable site for CO2 adsorption. The composite selectively adsorbs CO2 from the CO2/N2 mixture, with selectivity significantly higher than many other supported ILs. Furthermore, the selectivity increases with increasing IL ratio in the composite. This computational study, for the first time, demonstrates that IL/MOF composite might be potentially useful for CO2 capture.

Improving Gas Separation Performance of ZIF-8 by [BMIM][BF4] Incorporation: Interactions and Their Consequences on Performance

“…[8][9] IL-MOF combinations have been considered recently in the gas separation field. [10][11][12][13][14][15][16] For instance, Chen et al 17 incorporated IRMOF-1 composite and reported a CO 2 /N 2 selectivity of 70 at ambient conditions. To understand the effect of different types of ILs on the separation performances of IL-MOF systems, ILs with the same cations but different anions were studied.…”

Ionic Liquid/Metal–Organic Framework Composites for H2S Removal from Natural Gas: A Computational Exploration

“…[34][35][36][37][38] Some experimental and theoretical studies have shown that MOFs could be used as potential porous supporter for ILs. [39][40][41][42][43][44][45][46] Jiang and co-workers 42 first investigated the IL/IRMOF-1 composites for CO 2 /N 2 separation by molecule simulation, showing that the selectivity can be enhanced when introducing ILs into the pores of IRMOF-1. Later, this group further computationally explored the capabilities of MOF-supported IL membranes for CO 2 /N 2 separation in which the effect of 5 anions of ILs and the role of hydrophobic/hydrophilic framework were examined.…”

“…The bulk molar composition of the mixture was taken as H 2 S:CH 4 =0.001:0.999 (i.e., 1000 ppm of H 2 S), which can represent a typical concentration of H 2 S in crude natural gas 59. As done by others,42,45 the structures of all the IL/Cu-TDPAT composites were treated as rigid during adsorption simulations. Actually, we have done some…”

Recent advances in the synthesis and applications of metal organic frameworks doped with ionic liquids for CO 2 adsorption

“…Most of the studies regarding gas adsorption properties of MOF-supported ILs have been mainly computational simulations [141][142][143][144]. A composite of [BMIM][PF 6 ] IL supported on IRMOF-1 was investigated for CO 2 capture by molecular computation by Chen and coworkers [141].…”

“…A composite of [BMIM][PF 6 ] IL supported on IRMOF-1 was investigated for CO 2 capture by molecular computation by Chen and coworkers [141]. The [BMIM] + cation resided in the open pores of IRMOF-1, while the small [PF6] -anion was located in the metal cluster corner interacting strongly with the framework.…”