Ionic Liquid Molecules Research Articles

Advanced Techniques Using Ionic Liquids for Efficient Separation of Sugar Alcohols

Recently, increasing interest has been reported in applying ionic liquids (ILs) in separating alcohols and proteins, an important process for several industrial and pharmaceutical applications. Traditional separation processes are poorly effective, with low selectivity, high energy consumption, and environmental problems. This review presents special properties of ILs concerning tunability and remarkable solvation ability that hold great promise for separation processes. The IL stationary phases modified with certain functional groups can enhance the interaction between IL and target molecules, increasing separation efficiency. Notably, the amino group-modified ILs were able to separate proteins by charge and size, a greener bioseparation technique owing to the low volatility and easy recyclability of ILs. AI's role in designing highly selective ILs for particular targets is discussed. Design of ILs, selection of solvent, and process optimization will be developed by applying techniques such as machine learning, molecular modeling, and data mining. Further, the review discusses the economic and environmental benefits of IL-based separations, and an attempt is made to discuss its cost-saving and resource-efficiency aspects. Separation of sugar alcohols using ILs, along with a discussion on advanced techniques, has been presented given their tunable solubility and low volatility being regarded as main issues in enhancing the separation processes. It also discusses the design of task-specific ILs for separating methanol from ethanol, which shows high selectivity toward methanol. Finally, the history of IL development, with current challenges in separating alcohols and proteins, gives a view of future research related to sustainable separation using ILs.

Effects of microscopic and mesoscopic solvent properties on complex formation of nickel(II) ion with cyclic molecules in imidazolium-based ionic liquids

Effects of microscopic and mesoscopic solvent properties on complex formation of nickel(II) ion with cyclic molecules in imidazolium-based ionic liquids

Experimental measurements, thermodynamic modeling and molecular dynamics simulation of the multiphase equilibria of {1-butanol + n-butyl acetate + [EMIM][EtSO4]} systems at 101.3 kPa

Ionic liquids (ILs) are organic salts with normal melting temperatures lower than 373 K and have interesting properties to be used as environment-friendly solvents, as low volatility, high thermal stability, and easy containing and recycling ability. Besides, they are versatile molecules whose anions and cations can be changed to solubilize different organic compounds. For these reasons, ionic liquids can be used in many industrial applications, such as in separation processes as azeotropic distillation and liquid–liquid extraction, and, because of that, it is important to know the phase equilibrium behavior for equipment design for these processes. However, experimental data for systems containing ionic liquids are very scarce. This work aimed to analyze the fluid phase behavior of the 1-butanol + n-butyl acetate + [EMIM][EtSO4] system in liquid–liquid (LLE), vapor–liquid (VLE) and vapor–liquid–liquid equilibria (VLLE) at 101.3 kPa. LLE was analyzed in glass-jacketed vessels and VLE and VLLE were analyzed in a modified Othmer ebuliometer. Compositions of each phase sample were obtained from calibration curves with built-in functions of the refractive index and density. Experimental data were submitted to thermodynamic consistency tests and the consistent points were modeled with the Group Contribution Volume Translated Peng-Robinson (GC-VT-PR) and Non-Random Two-Liquid (NRTL) models. Vapor pressure and saturated liquid density data for the ionic liquid, necessary for the determination of the pure component parameters, were obtained from analytical methods. For the LLE, a phase stability test was also done to evaluate the data consistency by the Gibbs energy of the mixing surface and to determine the plait point. Molecular dynamics (MD) simulations, performed by NAMD software, were also conducted to understand the behavior of the multiphase fluid equilibria, by analyzing the structural properties of the components. Results of the thermodynamic modeling in terms of the deviations of temperature and mole fractions showed that these models were adequate to study the phase behavior of systems containing ionic liquids, while the dynamic simulations suggested that the ionic liquid molecules strongly interact with 1-butanol molecules when compared with the n-butyl acetate molecules.

Hydrodynamic Fluidic Pump Empowered Sensitive Recognition and Active Transport of Hydrogen Peroxide in 1D Channels.

Through synthetic chemistry, the development of molecular devices for the precise selective recognition and active transport of small molecules stands as one of the most ambitious objectives in extensive medical, environmental, and biological applications. The periodical channels of the metal-organic frameworks (MOFs) with excellent chemical affinity offer vast regulatory space for reaching this goal. Herein, by post-modifying fluorescent probes and ionic liquid molecules into the Zr-MOFs (NU-1000), a donor-acceptor (D-A) system within the periodical 1D channels is created to construct a hydrodynamic fluidic pump within the abundant 1D channels. Irradiation with light serves to initiate and direct fluid motion, expediting the transport of H2O2 molecules to the active site, thus boosting the sensor sensitivity through gas enrichment. The rapid mass transfer, characterized by a high flow rate and intensified interaction between the D-A system and H2O2 molecules, enables the detection of H2O2 at concentrations as low as 20 ppb. Besides, with the aid of incident light, the pump system exhibits active transport characteristics by transporting radicals derived from H2O2 against a concentration gradient, reaching a remarkable 10th cycle. The strategy of achieving active transport of small molecules through pore modification holds promise for advancing the development of artificial bioactive channels.

Tension ring-functionalized bicyclic ammonium ionic liquids as hypergolic fuels with superior energy density

Hypergolic ionic liquids are a new type of liquid propellants, and the energy density is critical to propulsion performance. We propose to combine cage structures with tensile rings to design and synthesize new ionic liquid molecules. Cycloalkane-substituted 1-aza-bicyclo[2.2.2]octane and 1,4-diazabicyclo[2.2.2]octane-like ionic liquids were synthesized using dicyanamide root as an anion, and their structure and properties were determined. The obtained ionic liquids possess higher energy density up to 1.87 kJ·mL−1. The three-membered ring substituent can increase the energy density of ionic liquids by 79.8 % and reduce the ignition delay time by 52.5 % than that of straight-chain alkanes. This work provides an important basis for the design and synthesis of the new type of hypergolic ionic liquids.

Prediction of solubility of CO2, H2S, and their mixture in ionic liquids using the Cubic Two State equation of state

In this work, the capability of the Cubic Two State (CTS) equation of state (EoS) has been evaluated using the solubility of carbon dioxide (CO2), hydrogen sulfide (H2S), and their mixture in ionic liquids (ILs). The imidazolium-based ILs with [BF4], [PF6], and [Tf2N] anions have been studied. The self-association between IL molecules, CO2, and H2S molecules has been considered to optimize the pure model parameters. In addition to self-association between similar molecules, the cross-association between CO2-IL and H2S-IL in the binary mixtures has been considered. The results show that the CTS EoS can predict (kij=0.0) the solubility of H2S and CO2 in ILs ranging from 1 to 1000 bar satisfactory. The average ARD value for binary CO2-IL and H2S-IL systems has been obtained 20.3 % and 9.02, respectively. The CTS model has been used to predict the phase behavior of ternary systems containing CO2H2S-[C4mim][PF6], CO2H2S-[C8mim][PF6], and CO2H2S-[C8mim][Tf2N] at various temperatures. Finally, the CTS results have been compared to soft-SAFT and PC-SAFT EoSs. The results show that simple association contribution and the cubic term of the CTS EoS can model the molecular interactions between gases and ILs satisfactory. The CTS model can be considered as a robust and efficient thermodynamic model for the prediction of separation of CO2 and H2S using ILs.

Effects of Heterogeneous Mixing of Imidazolium-Based Ionic Liquids with Alcohols on Complex Formation of Ni(II) Ion.

Understanding the complex formation of metal ions in room-temperature ionic liquids (ILs) is essential for the application of ILs in solvent extraction. Nevertheless, the research on metal complex formation in ILs lags behind other applications. The complex formation equilibria may be influenced by specific interactions among the metal ion, ligand molecule, and IL cation and anion. In the present investigation, the complex formation of Ni2+ with ethanol (EtOH) and methanol (MeOH) molecules in ILs, 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([CNmim][TFSA], where N represents the alkyl chain lengths of 2 and 8) was discussed in terms of the microscopic interactions among alcohol molecules, [CNmim]+ and [TFSA]-, and the mesoscopic mixing states of alcohols in [CNmim][TFSA], with N = 2-12. The microscopic interaction of alcohol molecules with the imidazolium ring H atoms in the ILs was evaluated by using ATR-IR and 1H and 13C NMR spectroscopies. The self-hydrogen bonding of alcohol molecules was clarified from the O-H stretching vibration of alcohol molecules. MeOH molecules can be more strongly hydrogen-bonded with themselves than EtOH molecules due to the less steric hindrance and the weaker dispersion force of MeOH with the IL cation's alkyl chain. In fact, small-angle neutron scattering (SANS) experiments revealed the more heterogeneous mixing of MeOH with the ILs by the self-hydrogen bonding among MeOH molecules than EtOH. The longer the IL cation's alkyl chain, the more the MeOH clusters significantly form. In contrast, the formation of EtOH clusters becomes weaker with elongating the alkyl chain. Ultraviolet (UV)-visible spectroscopic measurements on Ni2+-[CNmim][TFSA]-alcohol solutions with N = 2 and 8 revealed that di-, tetra-, and hexa-alcohol-Ni2+ complexes are formed in both the ILs. With N = 2, the stabilities of Ni2+-EtOH and Ni2+-MeOH complexes are comparable in the IL. However, with N = 8, the complexes are more stable in the EtOH solutions than in the MeOH solutions. This is because the less heterogeneous mixing of EtOH molecules with the IL results in the larger enthalpic contribution in the complex formation, as shown by the thermodynamic parameters estimated by the van't Hoff plots on the stability constants at several temperatures.

Observation of a Reversible Order-Order Transition in a Metal-Organic Framework - Ionic Liquid Nanocomposite Phase-Change Material.

Metal-organic framework (MOF) composite materials containing ionic liquids (ILs) have been proposed for a range of potential applications, including gas separation, ion conduction, and hybrid glass formation. Here, an order transition in an IL@MOF composite is discovered using CuBTC (copper benzene-1,3,5-tricarboxylate) and [EMIM][TFSI] (1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide). This transition - absent for the bare MOF or IL - provides an extended super-cooling range and latent heat at a capacity similar to that of soft paraffins, in the temperature range of ≈220°C. Structural analysis and in situ monitoring indicate an electrostatic interaction between the IL molecules and the Cu paddle-wheels, leading to a decrease in pore symmetry at low temperature. These interactions are reversibly released above the transition temperature, which reflects in a volume expansion of the MOF-IL composite.

Modification of ionic liquid and lactoferrin-based small molecules as potential therapeutics against SARS-CoV-2: Molecular docking disclosed the predictable results

Ionic liquid MIE-NH2 displays a new role in the development of modification of glycoproteins of lactoferrin through a reductive amination mechanism to synthesize versatile pharmaceuticals. This work introduces a new strategy of modification of lactoferrin by using methyl imidazolium N-ethylamine MIE-NH2, this ionic liquid linked to N-glycans in lactoferrin derivatives in simple method. The modification of lactoferrin with MIE-NH2 as a novel small molecule (SM-IL-Lf) contains active amino groups is confirmed by UPLC/ESI-QTOF and MALDI-TOF mass spectrometry. Molecular docking disclosed the bioactivity of modifying glycoproteins - small IL-Lf-molecules by elucidating its interactions with the inspected targets. This providing of small molecules IL-Lf released a wide display with different functions as significantly important drug candidates inhibiting the targets of main protease (Mpro), RNA dependent RNA polymerase (RdRp), transmembrane protease serine 2 (TMPRSS2), and Papain-like protease (PLpro). The probability of the modeling N-glycans from lactoferrin modified and designed as small IL-Lf-molecules to inhibit any of these targets was investigated to find out its potency inhibitor of SARS-CoV-2.

Revisit coupling of CO2 to ethylene carbonate with an integrated imidazolium and zinc halides catalyst by a study on its decomposition: Active center and mechanism

Coupling of carbon dioxide (CO2) to cyclic carbonates with an epoxide and further into linear carbonates as the indispensable solvents for the lithium-ion batteries has been being one of the hottest topics in transforming CO2 into high value-added chemicals. Nevertheless, the extremely ultrahigh purity requirement for them causes a low efficiency and a modest yield due to the undesired reactions and byproducts occurring in the separation and purification sections. In this work, a novel imidazolium based ionic liquid catalyst system with different anions and cations was studied by a thorough insight into the decomposition reaction of ethylene carbonate (EC), which reveals the synergistic mechanism of the composite catalysts both in section of cyclic carbonate separation from the catalyst for recirculated utilization and purification from the byproducts, and in section of synthesis with high efficiency. Effects of imidazolium cations and halogen anions in the ionic liquid molecule on EC decomposition were investigated by the elaborately designed experiments, thermodynamic estimations, molecular dynamics simulation and DFT assessment. It was found that combining imidazole salts and zinc halides can greatly boost the activity of EC synthesis and decomposition with the effective structure of catalytic center being [EMIm]ZnX4. Furthermore, it was indicated that Br- has a higher activity for EC synthesis and its reversed pyrolysis, while Cl- will promote a side reaction of ring-opening polymerization of EC. Finally, a most favorable catalyst composition with ZnBr2 and [EMIm]Br for EC synthesis was achieved with a high efficiency in synthesis and a low tendency to initiate the side reactions in separation section.

Impact of Ionic Liquids on the Physicochemical Behavior of Vesicles.

The effects of two ionic liquids (ILs), 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF4) and 1-butyl-1-methyl pyrrolidinium tetrafluoroborate ([bmp]BF4), on a mixture of phospholipids (PLs) 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC), 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE), and 1,2-dipalmitoyl-sn-glycero-3-phosphoglycerol (DPPG) (6:3:1, M/M/M, 70% PL) in combination with 30 mol % cholesterol (CHOL) were investigated in the form of a solvent-spread monolayer and bilayer (vesicle). Surface pressure (π)-area (A) isotherm studies, using a Langmuir surface balance, revealed the formation of an expanded monolayer, while the cationic moiety of the IL molecules could electrostatically and hydrophobically bind to the PLs on the palisade layer. Turbidity, dynamic light scattering (size, ζ-potential, and polydispersity index), electron microscopy, small-angle X-ray/neutron scattering, fluorescence spectroscopy, and differential scanning calorimetric studies were carried out to evaluate the effects of IL on the structural organization of bilayer in the vesicles. The ILs could induce vesicle aggregation by acting as a "glue" at lower concentrations (<1.5 mM), while at higher concentrations, the ILs disrupt the bilayer structure. Besides, ILs could result in the thinning of the bilayer, evidenced from the scattering studies. Steady-state fluorescence anisotropy and lifetime studies suggest asymmetric insertion of ILs into the lipid bilayer. MTT assay using human blood lymphocytes indicates the safe application of vesicles in the presence of ILs, with a minimal toxicity of up to 2.5 mM IL in the dispersion. These results are proposed to have applications in the field of drug delivery systems with benign environmental impact.

Multi-criteria computational screening of [BMIM][DCA]@MOF composites for CO2 capture

Ionic liquid (IL) can be inserted into metal organic framework (MOF) to form IL@MOF composite with enhanced properties. In this work, hypothetical IL@MOFs were computationally constructed and screened by integrating molecular simulation and convolutional neural network (CNN) for CO2 capture. First, the IL [BMIM][DCA] with a large CO2 solubility was inserted into 1631 pre-selected Computational-Ready Experimental (CoRE) MOFs to create hypothetical IL@MOFs. Then, given the temperature and pressure of adsorption and desorption, the CO2/N2 selectivity and CO2 working capacity of 700 representative IL@MOFs were assessed via molecular simulations. Based on the results, two CNN models were trained and used to predict the performance of other IL@MOFs, which reduces the computational costs effectively. By combining the simulation results and CNN model predictions, 22 IL@MOFs with top-ranked performance were identified. Three distinct ones IL@HABDAS, IL@GUBKUL, and IL@MARJAQ were chosen for explicit analysis. It was found that a desired balance between CO2/N2 selectivity and CO2 working capacity can be obtained by inserting the optimal number of IL molecules. This helps guide a novel design of IL@MOF composites with advanced performance on carbon capture.

Quantifying and Decoupling Molecular Interactions of Ionic Liquids with Gold Electrodes.

This work combined gold colloid probe atomic force microscopy (AFM) with a quartz crystal microbalance (QCM) to accurately quantify the molecular interactions of fluorine-free phosphonium-based ionic liquids (ILs) with gold electrode surfaces. First, the interactions of ILs with the gold electrode per unit area (, N/m2) were obtained via the force-distance curves measured by gold probe AFM. Second, a QCM was employed to detect the IL amount to acquire the equilibrium number of IL molecules adsorbed onto the gold electrode per unit area (NIL, Num/m2). Finally, the quantified molecular interactions of ILs with the gold electrode (F0, nN/Num) were estimated. F0 is closely related to the IL composition, in which the IL with the same anion but a longer phosphonium cation exhibits a stronger molecular interaction. The changes in the quantified interactions of gold with different ILs are consistent with the interactions predicted by the extended Derjaguin-Landau-Verwey-Overbeek theory, and the van der Waals interaction was identified as the major contribution of the overall interaction. The quantified molecular interaction is expected to enable the direct experimental-derived interaction parameters for molecular simulations and provide the virtual design of novel ILs for energy storage applications.

Phosphate-based ionic liquids for advanced interface modification in perovskite photovoltaics: Novel insights for ionic liquid molecule design

Interface modification stands out as a crucial method to enhance the performance of perovskite solar cells. This study explores the utilization of the ionic liquid 1-Methyl-3-propylimidazolium phosphate (MPIMPH), containing phosphate (PO43−) groups, as a modifier for SnO2/perovskite interfaces. Detailed investigations delve into the specific impact of IL MPIMPH on defects in tin dioxide, perovskite defects, perovskite crystallization, morphology, and overall device performance. Initially, Density Functional Theory (DFT) is employed to evaluate the defect passivation potential of different anions on tin vacancies within the SnO2 matrix, revealing the exceptional defect passivation ability of the PO43− group. Chemical interactions between ILs MPIMPH and SnO2, as well as perovskite, are confirmed, establishing a fundamental basis for interface defect passivation. ILs-based interface modification enhances interface contact, influencing the lead iodide conversion into perovskite and perovskite crystallization, ultimately leading to the formation of high-quality perovskite thin films. ILs also effectively suppress interfacial charge recombination and optimize the energy alignment of the SnO2/perovskite interface to enhance carrier extraction. Benefiting from the interface modification with ILs, the optimized device achieved an impressive device efficiency of 24.24 % with remarkable durability. This work provides an novel aspect for designing ionic liquids to enhance interface modification, contributing to upscaling and application of perovskite photovoltaics.

Investigation of the Tribological Properties of Hybrid Additive-Modified Water-Based Lubricating Fluid

Water-based lubricating fluids (WBLFs), known for their significant environmental benefits, are the focus of this study. The properties of WBLFs directly influence lubricated mechanisms’ longevity and operating efficiency. WBLFs are enhanced using additives, which must improve their properties and, at the same time, remain environmentally friendly. This study combines bis(2-hydroxyethyl) ammonium erucate protic ionic liquid and titanium oxide nanoparticles to formulate the hybrid additive. The lubricity was investigated using Alumina/Bearing steel and WC/Bearing steel friction pairs in a reciprocating ball-on-plate tribo-tester. The results show that protic ionic liquid can significantly improve lubricity and the corrosion-preventing ability of the base fluid. Applying a hybrid additive further improved the wear reduction ability in the WC/Bearing steel friction pair. However, the wear reduction ability was diminished when a hybrid additive was used to lubricate the Alumina/Bearing steel friction pair. The proposed lubricity improvement mechanism is based on forming an adsorption layer of ionic liquid molecules and rolling and tribo-sintering titanium oxide nanoparticles.

A Tunable Hydrophilic-Hydrophobic, Stimulus Responsive, and Robust Iridescent Structural Color Bionic Film with Chiral Photonic Crystal Nanointerface.

Bio-inspired in nature, using nanomaterials to fabricate the vivid bionic structural color and intelligent stimulus responsive interface as smart skin or optical devices are widely concerned and remain a huge challenge. Here, the bionic flexible film is designed and fabricated with chiral nanointerface and tunable hydrophilic-hydrophobic by the ultrasonic energy perturbation strategy and crosslinking of the cellulose nanocrystals (CNC). An intelligent nanointerface with adjustable hydrophilic and hydrophobic properties is constructed by the supramolecular assembly using a smart ionic liquid molecule. The bionic flexible film possessed the variable hydrophilic-hydrophobic, stimulus responsive, and robust iridescent structural color. The reflective wavelength and the helical pitch of the film can be easily modulated through the ultrasonic energy perturbation strategy. The bionic flexible film by covalent cross-linking has excellent robustness, good elasticity and flexibility. The tunable brilliant structural color of the chiral nanointerface is attributed to the surface charge change of the CNC photonic crystal, which is disturbed by ultrasonic energy perturbation. The bionic flexible film with tunable structure color has intelligent hydrophilic and hydrophobic stimulus response properties. The chiral bionic materials have potential applications in smart skin, optical devices, bionic materials, robots, anti-counterfeiting, colorful displays, and stealth materials.

Influence of shear deformation on the formation of dynamic structure in protic ionic liquids. Representation of the temperature dependence of viscosity within the framework of Angell’s fragility concept

The rheological properties of a liquid containing two types of basic centers and hydroxyl groups (BGE-Im), as well as protic ionic liquids (ILs) derived from it, were studied in a wide range of shear rates (γ̇) (10−6–103 s−1) at various temperatures from 10 to 50 °C. Viscosity (η) of the BGE-Im does not depend on the scanning direction of shear stress (σ), i.e. this compound behaves like a Newtonian fluid over the entire range of σ. The dependence log η (1/T) of BGE-Im in Arrhenius coordinates is linear. Protonation of basic centers of BGE-Im leads to a strong increase in the viscosity of ILs obtained on its basis, and the temperature dependence of the viscosity of these ILs is described by the Vogel–Fulcher–Tammann (VFT) equation. It has been established that in the region of low shear rates, the viscosity of the ILs increases with decreasing shear rate, which leads to the appearance of a yield stress (σY). This indicates the formation of a fluctuation rheopectic structure in the ILs. In this sense, ILs are heterogeneous systems and their behavior is similar to that of highly concentrated suspensions and emulsions. For the first time, a quantitative comparison between the parameters of the VFT equation, the fragility (according to Angell’s model) of ILs, the relative coordination number of ILs molecules and the rheological yield stress characterizing the shear-induced fluctuation rheopectic structure of ILs has been made and the relationship between these characteristics has been shown.

Smart emulsion system driven by light‐triggered ionic liquid molecules and its application in eco‐friendly water‐saving dyeing

AbstractThe smart emulsification and demulsification system with the light response is a useful tool in various industries, including green chemistry, catalytic reaction, pharmaceuticals, and environmental remediation. Herein, an ionic liquid crystal compound with a light triggered switch based on the azobenzene group [(4‐{3‐methyl‐1‐[3‐(8‐octyloxyoctyl)oxy‐4‐oxobutanoyl]imidazo‐lium‐1‐yl}octyl)oxy] ‐N‐(4‐methylphenyl)benzene‐1,2‐diazene bromide (MOIAzo), was designed and synthesized, which could cause reversible transition between emulsification and demulsification through the light trigger. The ionic liquid has an efficient photoinduced liquefaction process, which dramatically lowers the melting point of ionic liquids from 79 to 9.2 oC. This significantly broadens the liquid state temperature of the ionic liquid crystal. The ionic liquid crystal MOIAzo exhibits both photoinduced and thermally induced nematic liquid crystal properties. The smart emulsion system was effectively employed in an eco‐friendly water‐saving dyeing process of cationic dyes for cationic dyeable polyester (CDP) fabrics, which used only half the amount of water compared with the conventional water bath dyeing method. After dyeing, the oil and water phases can be efficiently separated through the light irradiation, and the oil phase can be reused for the subsequent dyeing process. This novel smart emulsion dyeing method greatly reduces the water consumption and wastewater discharge. MOIAzo as a light‐triggered ionic liquid molecule opens up new dimensions in green chemistry.

Ionic liquid-ethanol mixed solvent design exemplified for the decarbonization of shale gas and biogas

Shale gas and biogas, recognized as “clean” energy sources, hold the potential to replace fossil fuels, necessitating efficient decarbonization processes. This study proposes a mixed solvent, combining ionic liquid (IL) and ethanol, for a cost- and energy-effective decarbonization approach. Initially, a computer-aided molecular method optimizes the IL molecule structure, identifying 1-hydroxy-3-methyl-pyridinium trifluoroacetate ([OHMPY][CF3COO]) through solving a formulated mixed-integer nonlinear programming (MINLP) problem. The [OHMPY][CF3COO]-ethanol mixed solvent's performance is validated in shale gas and biogas decarbonization across diverse gas compositions and feed conditions. A comprehensive comparison with the traditional MDEA-based CO2 removal process is conducted, evaluating energy, economic, and environmental aspects. Results indicate that the [OHMPY][CF3COO]-ethanol decarbonization process offers 30.65%-41.48% power savings, a 3.68%-17.18% reduction in investment costs, and an 18.08%–22.45% decrease in CO2 emissions. These findings underscore the significant potential of the proposed IL-ethanol binary mixed solvent in decarbonization processes.

A novel synergistic intensification method for CO2 absorption by metal salt and task-specific ionic liquids hybrid solvent in microchannel reactor

A novel metal salt-promoting mass transfer intensification method for CO2 absorption into task-specific ionic liquids aqueous solution was proposed. The mass transfer intensification and intrinsic mechanisms of different concentrations of metal salts (NaBF4, KBF4, KCl, and CuCl2) with task-specific ionic liquids (1-aminopropyl-3-methylimidazolium tetrafluoroborate [Apmim] [BF4]) aqueous solutions for CO2 capture process were visually investigated using a microchannel reactor. The results showed that adding metal salts could remarkably enhance the interaction between metal cations and ionic liquid anions, thereby decreasing the interaction between anions and cations within the ionic liquid molecules and promoting the chemical reaction between ionic liquid cations and CO2. Under the condition of the same salt concentration, the addition of KBF4 has more obvious enhancement for mass transfer in CO2 absorption process. The mass transfer coefficient increases as the gas-liquid phase flow rate rise under slug flow condition. In addition, based on the effects of metal salt concentration, absorbent density, and gas-liquid phase flow rate on the CO2 volumetric mass transfer coefficient kLa, a new correlation for predicting the volumetric mass transfer coefficient of CO2 absorption into the hybrid solvent in microchannel reactor was proposed and validated.