Properties of ionic liquid mixtures of [NH₂e‐mim][BF₄] and [bmim][BF₄] as absorbents for CO₂ capture

Abstract

Although the use of ‘task‐specific’ amine‐functionalized imidazolium‐based ionic liquids (ILs) such as [NH2emim][BF4] and conventional imidazolium‐based ILs [bmim][BF4]), as absorbents for CO2 capture, possesses some unique advantages, they have a number of disadvantages when independently used for CO2 capture. This study examined a series of binary liquid mixtures of [NH2emim][BF4] and [bmim][BF4] for CO2 capture, exploiting the advantages and reducing the disadvantages of each of the components. The CO2 absorption performances of the mixtures were investigated as well as their physicochemical properties. Densities, viscosities, and surface tensions of the mixtures of varying molar fractions of [NH2e‐mim][BF4] (from 0.2–0.5 mol/mol) were experimentally measured over a temperature range of 298.0–343.0 K at a fixed pressure of 0.1 MPa. Thermal expansion coefficients, excess logarithmic viscosities, surface entropies, and surface enthalpies were calculated based on the experimental data. All the estimated physicochemical properties in a mixture with a mole fraction of [NH2e‐mim][BF4] of 0.4 had variation characteristics significantly different from those in mixtures with other mole fractions, which might be attributed to the large interaction between the two kinds of IL components and showed a positive effect on CO2 absorption and desorption. The above laws were consistent with those of the CO2 capture performances of the IL mixtures basically. An IL mixture containing 0.4 mol/mol [NH2e‐mim][BF4] and 0.6 mol/mol [bmim][BF4] would be an optimal CO2‐capturing absorbent. The findings in this study may enrich the database and provide a theoretical support for CO2 capture with IL mixtures. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd.

Hydrophobic Functional Deep Eutectic Solvents Used for Efficient and Reversible Capture of CO2

“…Ionic liquids (ILs), which have many unique properties, such as high thermal stability, negligible vapor pressure, high CO 2 capacity, and adjustable structure, are good candidates for CO 2 absorption. − Normal ILs, − which only have physical interaction with CO 2 , can hardly be used for CO 2 capture from flue gas. Functional IL for CO 2 absorption was first reported by Davis et al, and the CO 2 capacity could reach almost 0.5 mol CO 2 /mol IL at 22 °C and ambient pressure.…”

Contemporary Advancement of Cholinium-Based Ionic Liquids for Protein Stability and Long-Term Storage: Past, Present, and Future Outlook

“…Furthermore, molecular docking results suggested the possibility of interactions between ILs and protein that are responsible for the stabilization of β-LG in [Chn]­[Bit], [Chn]­[DHP] and [Chn]­[Ac] . It has also been documented in literature that ILs, when mixed in definite proportions, abrogate the negative effect of one IL by the other IL, giving rise to the advantageous characteristics of the resultant mixture . Inspired by this study and taking forward their previous study, Sindhu et al considered a mixture of ILs to counteract the deleterious action of [Chn]­[I] on β-LG structure.…”

“…According to the literature discussed in earlier sections, it has been significantly demonstrated that [Chn]­[DHP] possesses exceptionally high biocompatibility toward proteins (see refs − , , − , , , , , − , , , − , , and ). A key factor that influences the stability of proteins in hydrated ILs is the kosmotropicity of the constituent ions, which is directly related to water assembly around proteins.…”

Experimental investigation of CO2 absorption enthalpy in conventional imidazolium ionic liquids

“…Thus, CO 2 absorption experiments were conducted using four kinds of ILs with the same cation but different anions. Many studies have shown that imidazolium‐based ILs demonstrate noticeable CO 2 absorption capacity . The cation [BMIm] + combined with different anions ([AC] − , [BF 4 ] − , [L‐lactate] − , and [PF 6 ] − ) were therefore investigated.…”

“…,33 Thus, CO 2 absorption experiments were conducted using four kinds of ILs with the same cation but different anions. Many studies have shown that imidazolium-based ILs demonstrate noticeable CO 2 absorption capacity [34][35][36][37]. The cation[BMIm] …”