The Role of Binary Mixtures of Ionic Liquids in ZIF-8 for Selective Gas Storage and Separation: A Perspective from Computational Approaches

Abstract

Carbon dioxide is one of the major causes of global climatic changes. Efficient separation of CO 2 from different gaseous mixtures can be helpful in flue gas separation, gas sweetening, natural gas processing, and so forth. Adsorption in porous materials is emerging as one of the best techniques in this regard. Also CO 2 is easily soluble in ionic liquids (ILs). Hence, we have designed IL (designer solvent)-based composite materials by impregnating ILs into the pores of zeolitic imidazolate framework (ZIF)-8. In this study, we have computationally explored the properties of such composites. Mixture of different types of ILs can enhance composite material properties and leads to efficient gas separation. We studied both simple and binary mixtures of ILs in the nanopores of ZIF-8 using density functional theory (DFT) and grand canonical Monte Carlo (GCMC) methods. ZIF-8 retained its core structure even after IL incorporation, and also the ILs were well dispersed in the confinement. Gas adsorption studies were performed for gases such as CO 2 , N 2 , and CH 4 and their binary mixtures. Both singlecomponent and binary mixture adsorptions were similar at a pressure less than 1 bar. The selectivity calculated from the gas mixture adsorption elicited that our materials show good selective adsorption of CO 2 compared with the other two gases. The binary mixture of ILs enhanced the CO 2 selectivity by 3.5-fold higher than simple ILs@ZIF-8. Especially, the composite with hydrophobic− hydrophobic binary IL mixture has higher CO 2 selectivity than other materials, attributed to the strong interactions between CO 2 and IL anions. The like−like hydrophobic ion pair and the fluorine content in the IL enhanced the selective adsorption of CO 2 . The binary IL mixtures at the confinement can be a novel alternative to the prevailing materials in gas separation applications.

Metal–Organic Framework Nanoparticles Power DNAzyme Logic Circuits for Aberrant MicroRNA Imaging

“…Recently, metal–organic frameworks (MOF NPs) have attracted great attention in selective catalysis, gas storage and separation, − and drug delivery − owing to their large surface area, high and tunable porosity, and good functionalization . In particular, zeolitic imidazolate framework-8 nanoparticles (ZIF-8 NPs), a subclass of MOF NPs, have been utilized as a smart nanocarrier for accommodating functional nucleic acids containing siRNA, CpG, and DNAzyme by electrostatic interactions. − Moreover, the nanoscale ZIF-8 NPs can be delivered into cells via the endocytosis pathway and then decomposed under acidic conditions of endo-lysosomes to motivate the controlled cargo release. − Recent studies have found that Cu 2+ -doped ZIF-8 NPs (Cu/ZIF-8 NPs) not only maintain the unique properties of ZIF-8 NPs but also supplement an adequate amount of DNAzyme cofactor to implement the biocatalytic operation of the Cu 2+ -dependent DNAzyme in living cells. , Thus, the Cu/ZIF-8 NP-based nanoplatform could be employed as a versatile self-driven nanocarrier for the efficient delivery of DNAzyme logic circuits into cells.…”

Defect-enhanced selective ion transport in an ionic nanocomposite for efficient energy harvesting from moisture

“…Compared with anions, the cationic part of ILs with a hydrophobic alkyl chain and an imidazolium ring tends to hold stronger interactions with the ZIF-8 framework. 33,34 Intriguingly, defects within ZIF-8 frameworks can enhance their interactions with cations (Fig. 1(e)).…”

A Review on Removal of Carbon Dioxide (CO2) using Zeolitic Imidazolate Frameworks: Adsorption and Conversion via Catalysis

“…Thus, ZIFs materials containing ILs provided high adsorption capacity. The use of binary ILs enhanced the CO2 selectivity by 3.5-fold compared to simple ILs@ZIF-8 [141] . A binary ILs with both hydrophobic-hydrophobic properties exhibited higher CO2 selectivity.…”