Amount Of Ionic Liquid Research Articles

Fundamental investigation on a new methodology to fabricate thin ion gel membranes for CO2 separation

A new method for fabricating thin ion gel membranes is proposed in this study. A precursor solution of a hydrophobic tough ion gel composed of an interpenetrating polymer network (IPN) and 80 wt% ionic liquid (IL) was spin coated onto a water-soluble sacrificial layer (poly(sodium 4-styrenesulfonate) (PSS-Na)) and a thin ion gel membrane was obtained after dissolving the sacrificial layer in IL-saturated water. Subsequently, the thin ion gel membrane was transferred onto a porous support membrane for obtaining a thin-film composite (TFC) membrane. The TFC membranes showed the same CO2 permeability as the thick ion gel membrane prepared using the same ion gel precursor solution, which indicates that the thin ion gel layer on the TFC membrane was defect free and contained the desired amount of IL. The TFC membrane with 9.3-μm-thick ion gel layer displayed the CO2 permeance of 98.2 GPU and CO2/N2 permselectivity of 31. This CO2 permeation performance was maintained for at least 200 h, indicating the good long-term stability of the prepared thin ion gel layer. The proposed method for forming a thin ion gel layer can be applied to other ion gels with different ILs.

Ionic Liquids toward Enhanced Carotenoid Extraction from Bacterial Biomass.

Carotenoids are high added-value products primarily known for their intense coloration and high antioxidant activity. They can be extracted from a variety of natural sources, such as plants, animals, microalgae, yeasts, and bacteria. Gordonia alkanivorans strain 1B is a bacterium recognized as a hyper-pigment producer. However, due to its adaptations to its natural habitat, hydrocarbon-contaminated soils, strain 1B is resistant to different organic solvents, making carotenoid extraction through conventional methods more laborious and inefficient. Ionic liquids (ILs) have been abundantly shown to increase carotenoid extraction in plants, microalgae, and yeast; however, there is limited information regarding bacterial carotenoid extraction, especially for the Gordonia genus. Therefore, the main goal of this study was to evaluate the potential of ILs to mediate bacterial carotenoid extraction and develop a method to achieve higher yields with fewer pre-processing steps. In this context, an initial screening was performed with biomass of strain 1B and nineteen different ILs in various conditions, revealing that tributyl(ethyl)phosphonium diethyl phosphate (IL#18), combined with ethyl acetate (EAc) as a co-solvent, presented the highest level of carotenoid extraction. Afterward, to better understand the process and optimize the extraction results, two experimental designs were performed, varying the amounts of IL#18 and EAc used. These allowed the establishment of 50 µL of IL#18 with 1125 µL of EAc, for 400 µL of biomass (cell suspension with about 36 g/L), as the ideal conditions to achieve maximal carotenoid extraction. Compared to the conventional extraction method using DMSO, this novel procedure eliminates the need for biomass drying, reduces extraction temperatures from 50 °C to 22 ± 2 °C, and increases carotenoid extraction by 264%, allowing a near-complete recovery of carotenoids contained in the biomass. These results highlight the great potential of ILs for bacterial carotenoid extraction, increasing the process efficiency, while potentially reducing energy consumption, related costs, and emissions.

Ionic Liquids as Cathode Additives for High Voltage Lithium Batteries

AbstractTwo oxalatoborate ionic liquids (ILs), which are commonly utilized as electrolyte additives that form a protective layer on the cathode surface, are investigated for the first time as electrode additives. Cathodes based on LiNi0.5Mn1.5O4 (LNMO) containing 3 wt % ILs, i. e., “IL‐enriched cathodes”, exhibit capacity values above 120 mAh/g with high Coulombic efficiencies throughout cycling over 200 times. A cathode without ILs also exhibits a capacity of 119 mAh/g but its Coulombic efficiency becomes low and unstable after 109 cycles. In addition, when 0.3 M ILs are added to conventional carbonate‐based electrolytes, the battery cycle life improves but there is a reduction in the capacity probably due to low ionic conductivity of the electrolyte mixtures. Post‐mortem analyses of electrodes retrieved from cycled cells highlight less electrolyte decomposition and less cathode corrosion, enabled by using the IL as the additive in LNMO, which are confirmed by a particle shape with smooth surface identical to the fresh cathode. The study demonstrates that oxalatoborate ILs can be used as the electrode additive, and this provides a new concept for cathode formulations for high performance batteries with a small amount of ILs.

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.

Advanced Uranium Removal with Pure, Nonfluorinated Ionic Liquids: Fine-Tuning Hydrophilic and Hydrophobic Properties for Enhanced Selectivity.

Ionic liquids (ILs) have significant potential for eco-friendly extraction of uranium from aqueous solutions, which is critical for nuclear technology, fuel cycle management, and environmental protection. This study examines the impact of the adjustable hydrophobic/hydrophilic properties of ILs on the removal of uranium(VI) (UO22+) from aqueous solutions utilizing both a novel hydrophilic IL (1-butoxyethyl-1-methylmorpholinium butoxyethylphosphite - Mor1-2O4-BOEP) and 1-heptyl-1-methylmorpholinium heptylphosphite (Mor1-7-HP) as an example of a hydrophobic IL with a similar structure. The transfer mechanism of uranyl ions from water to organic or solid phases closely depends on the physicochemical properties of ILs, especially their hydrophobicity. The hydrophobic Mor1-7-HP extracts uranyl via neutral complex formation as UO2(NO3)2-(Mor1-7-HP)2. Conversely, hydrophilic Mor1-2O4-BOEP induced selective precipitation as UO2(NO3)-(BOEP), transferring uranyl to the solid phase. Optimization of the working parameters, in terms of acidity of the aqueous solution and amount of ILs used, allowed the extraction of over 98% of U(VI). The stoichiometry of the organic complex and the precipitate was determined using physicochemical techniques. These tunable H-phosphonate-based ILs have advantages over traditional solvent extraction and conventional ILs, allowing easier handling, improved selectivity, and lower environmental impact. This work advances uranium separation techniques with applications in hydrometallurgy, particularly in the treatment of wastewater and radioactive waste for sustainable uranium recovery.

Ionic liquids and Graphene: The ultimate combination for High-Performance supercapacitors

Ionic liquids (ILs), due to their tunable propensities and properties, are discussed as a new class of solvents for scientific and industrial applications. Developing novel processes and applying ionic liquids further accelerate the growth of our fundamental and engineering understanding.In this work, the structure of four ILs, 1-ethyl-3-methylimidazolium tetrafluoroborate formate (Emim+BF4−)/chloride (Emim+Cl−)/Nitrate (Emim+NO3−), and thiocyanate (Emim+SCN−) is reported. Then via employing classical molecular dynamics and well-tempered metadynamics simulations their dynamics are investigated. The dynamics of ILs are represented by studying mean squared displacements. Additionally, the increased size and weight of anions interacting with the Emim+ cation cause the dynamics to become slow. Therefore, due to the higher molecular weight, the BF4− anion has lower diffusion than any other. Indeed, radial distribution functions between cations and anions reveal the structural arrangement in ILs. On the other hand, it is unexpectedly found that a certain amount of ILs are distributed near the electrode surface. Such phenomena occur because of the relatively strong ionic interactions between cations and anions; also, the π–π stacking between cations and graphene caused their interactions to become stronger. Furthermore, the atoms in molecules (AIM) analyses identified several interatomic interactions between the ILs and graphene. The free energy values for the ILs at their global minima are about ∼ -271.79, −267.93, −251.37 kJ mol−1 and ∼ -241.98 kJ mol−1 in systems Emim+/Cl−, Emim//NO3−, Emim+/SCN−, and Emim+/BF4−, respectively. Our findings represent a crucial step towards interpreting the complex interactions and nanostructures at the electrolyte–electrode interface, which could be beneficial for designing high-performance supercapacitors in energy storage using carbon electrodes and IL electrolytes in experiments.

Ionic Liquids, Synthesized and Utilized by Greener Methods, for the Application in High-Voltage Lithium-Ion Batteries

Due to their high energy density and reliability, lithium-ion batteries (LIBs) are a crucial energy storage system for portable electronic devices, which has dominated the market for more than 30 years. To increase their energy density even more, it is imperative to replace the commonly employed cathode materials (such LiCoO2) with cathode materials that can operate at higher potentials, like LiNi0.5Mn1.5O4 (LNMO) working at 4.7V vs Li+/Li. However, standard electrolytes, typically containing carbonate-based solvents (e.g., LP30), are unstable at such high potentials and suffer from oxidation decomposition. To mitigate this problem, ionic liquids (ILs) have recently been proposed as an additive to them. Despite this, their application in industrial-scale is hindered by the high-cost and environmentally unfriendliness of their synthesis [1]. In this study, ILs containing oxalatoborate anions—known to form the so-called cathode-electrolyte interphase (CEI), a protective layer on the cathode surface [2]—have been obtained by using mostly water as solvent, to minimize the impact of the synthesis on the environment. Four different ILs have been synthesized: N-ethoxyethyl-N-methylpiperidinium bis(oxalato)borate (PIP1,2O2BOB), N-ethoxyethyl-N-methylpiperidinium difluoro(oxalate)borate (PIP1,2O2DFOB), N-propyl-N-methylpiperidinium bis(oxalato)borate (PIP1,3BOB) and N-propyl-N-methylpiperidinium difluoro(oxalate)borate (PIP1,3DFOB). All of them have been characterized by IR spectroscopy and thermal analysis (DSC and TGA). The thermal analyses highlighted that all the ILs are thermally stable up to 280°C. Furthermore, PIP1,2O2DFOB and PIP1,2O2BOB did not show any crystallization behavior even at sub-zero temperatures, but only a glass-transition (at -70 °C and -30 °C, respectively). The improved liquid property is related to the presence of an ether oxygen in the cation structure.The four ILs have been then used as the additive for LP30 at a concentration of 0.3M and the resulting mixtures have been tested in Li|LP30+IL|LNMO coin-cells at 1C (147 mA g-1) for over 150 charge/discharge cycles. The results obtained showed that the addition of the ILs to the electrolyte has ensured more stable charge/discharge cycles, with higher coulombic efficiency and improved discharge capacity retention especially in the case of BOB-based ILs, while Li|LP30|LNMO cells prepared as a reference failed after about 100 cycles. On the promise that the ILs play an important role at the surface of cathode, another approach has been tested: 3 wt% of IL has been added directly to the slurry during the preparation of LNMO electrodes. These IL-added electrodes have been tested in Li|LP30|LNMO+IL coin-cells. Remarkable improvements in the stabilities of the cells have been observed also in this case. In IL-added electrodes, the total amount of IL in the system is almost 40 times smaller than that used in LP30+IL mixtures as the electrolytes. These results show that presence of ILs closer to the electrode is crucial to obtain an improvement of the stabilities of high-voltage cathodes. The combination of greener synthesis and utilization is expected to enhance the sustainability of LIBs.[1] E. Simonetti, M. De Francesco, M. Bellusci, G. Kim, F. Wu, S. Passerini, G. B. Appetecchi, ChemSusChem, 2019, 12, 4946– 4952[2] A. Tsurumaki, M. Branchi, A. Rigano, R. Poiana, S. Panero, M.A. Navarra, Electrochimica Acta, 2019, 315, 17-23 Figure 1

One-dimensional sepiolite confined ionic liquids structure to improve the electrochemical performance of polyethylene-oxide based composite polymer electrolyte

Polyethylene-oxide (PEO) based composite polymer electrolytes (CPEs) with one-dimensional sepiolite confined ionic liquids (ILs) structure is constructed to further improve Li+ conductivity and reduce cost. Silicon nanorods (SNRs) is obtained by microwave-assisted acid activation of sepiolite and then ILs is confined into SNRs by supercritical CO2 fluid. The specific surface area of SNRs reduces from 170.88 m2 g-1 to 2.19 m2 g-1 after ILs confining, and the morphology and component of ILs in SNRs channel are clearly detected, indicating that the SNRs confined ILs structure (ILs@SNRs) is successfully obtained. The Li+ conductivity of CPEs increases from 1.40 × 10-6 S cm-1 to 0.922 × 10-4 S cm-1, which indicates that ILs confined in SNRs provide a fast channel for Li+ transmission. Besides, the reduction of PEO crystallinity is also favorable to Li+ transmission. The corresponding lithium symmetrical battery and LiFePO4 battery has excellent electrochemical performances. The good rate performance is attributed to the high Li+ migration number of 0.261 compare to 0.122 of PEO. Compared with the simple mixing of polymer and ILs, the confined ILs in SNRs channel will not be lost, which maintains the stability of Li+ transmission and reduces the consumption amount of ILs thus greatly reducing the cost of CPEs.

High-Performance Sustainable Electrochromic Devices Based on Carrageenan Solid Polymer Electrolytes with Ionic Liquid.

The development of sustainable functional materials with strong potential to be applied in different areas has been growing and gaining increasing interest to address the environmental impact of current materials and technologies. In this scope, this work reports on sustainable functional materials with electrochromic properties, based on their increasing interest for a variety of applications, including sensing technologies. The materials have been developed based on a natural derived polymer, carrageenan, in which different amounts of the ionic liquid (IL) 1-ethyl-3-methylimidazolium thiocyanate ([EMIM][SCN]) were blended. It is shown that the addition of different amounts of IL to the carrageenan matrix does not affect the properties of the samples in terms of morphology or physicochemical and thermal properties, the most significant difference being the increase of the ionic conductivity with increasing IL content, ranging from 2.3 × 10-11 S·cm-1 for pristine carrageenan to 4.6 × 10-4 S·cm-1 for the samples with 5 and 60 wt % IL content, respectively. A electrochromic device has been developed based on the different IL/carrageenan samples as electrolyte and poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS) as electrodes. Spectroelectrochemistry testing demonstrates functional devices at low voltages between 0.3 and -0.9 V. Among the different samples, the one with 15 wt % IL content presents the best conditions for application, presenting an oxidation time of 6 s, a reduction time of 8 s, and a charge density of 1150 and 1050 μC·cm-2 for oxidation and reduction, respectively. The same sample also presents excellent optical density as a function of load density, presenting an optical switch (Δ%Tx) of 99%. Thus, it is demonstrated that it is possible to develop high efficiency and sustainable electrochromic devices based on natural polymers and ionic liquids.

Multilevel Comparison of Ionic Liquid Separation of a Methanol/Methyl Acetate/Water Mixture

This paper aimed to investigate whether ionic liquids (ILs) with excellent phase equilibrium abilities were also economically superior at the process level. Comprehensive comparisons of seven different types of ILs for the separation of a methanol/methyl acetate/water mixture were performed from molecular, phase equilibrium, to the process level. The validated NRTL model was used for phase equilibria and process simulation and COSMO-based sigma profiles for mechanism analysis. Energy consumption, energy cost, and total annual cost (TAC) were carried out to quantify process performances. Heat pump-assisted IL-extractive distillation processes were proposed. The results indicated that the heat pump-assisted schemes saved the TAC up to 51.2%. The process economic performances of 1-ethyl-3-methylimidazolium acetate ([EMIM][Ac]), 1-hexyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium methylsulfate, and 1-ethyl-3-methylimidazolium thiocyanate were equally well, while that of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide was the worst at all levels. The TAC savings of the [EMIM][Ac] process ranged from 3.4 to 48.2% compared with the latter six ILs. The order of performance of ILs in terms of relative volatility or binary phase diagram was nearly the same as the process level, while using the minimum amount of ILs required to break azeotropes as an indicator was of a different order.

Effect of liquid confinement on regioselectivity in the hydrosilylation of alkynes with cationic Rh(I) N-heterocyclic carbene catalysts.

Polymeric mesoporous monoliths were prepared via ring-opening metathesis polymerization (ROMP) from norbornene (NBE), 1,4,4a,5,8,8a-hexahydro-1,4,5,8-exo,endo-dimethanonaphthalene (DMN-H6), tris(norborn-2-enylmethylenoxy)methylsilane and the 1st-generation Grubbs catalyst [RuCl2(PCy3)2(CHC6H5)] in the presence of 2-propanol and toluene and surface grafted with 1-(2-((norborn-5-ene-2-carbonyl)oxy)ethyl)-3-ethyl-1H-imidazol-3-ium tetrafluoroborate. Subsequently, a supported ionic-liquid-phase (SILP) system was created by immobilizing the ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF4] with the cationic catalyst [Rh((1-pyrid-1-yl)-3-mesitylimidazol-2-ylidene)(COD)+BF4-] (Rh-1; COD = 1,4-cyclooctadiene) dissolved therein. The regio- and stereoselectivity of Rh-1 dissolved in the IL and supported on the mesoporous monolith, referred to as Rh@SILPROMP, in the hydrosilylation of 1-alkynes with HSiMe2Ph was studied and compared to that of the homogeneous catalyst Rh-1 under biphasic conditions using methyl tert-butyl ether (MTBE) as a second organic phase. Different amounts of IL were used, which allowed for the creation of SILPs with different layer thicknesses. Rh@SILPROMP provided by far better β-(Z) selectivity for both aromatic and aliphatic 1-alkynes in comparison to Rh-1 used under biphasic conditions. The highest β-(Z) selectivity was obtained with the thinnest IL layer. No leaching of the IL or rhodium from the SILP system into the organic phase was observed, resulting in virtually metal-free hydrosilylation products. The data obtained with Rh@SILPROMP were also compared with those from previous studies with Rh-1 in the same IL supported on polyurethane-derived mesoporous monolithic supports (Rh@SILPPUR) and on mesoporous SBA-15 (Rh@SILPSBA-15). For the first time, the use of a liquid confinement created by both a SILP and the support itself to tune the transition state of an organometallic catalyst by non-covalent interactions and thus stereo- and regioselectivity is outlined.

Adsorption and thermal evolution of [C1C1Im][Tf2N] on Pt(111).

In the context of ionic liquid (IL)-assisted catalysis, we have investigated the adsorption and thermal evolution of the IL 1,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide ([C1C1Im][Tf2N]) on Pt(111) between 100 and 800 K by angle-resolved X-ray photoelectron spectroscopy and scanning tunneling microscopy. Defined amounts of IL in the coverage range of a complete first wetting layer were deposited at low temperature (100-200 K), and subsequently heated to 300 K, or directly at 300 K. At 100 K, the IL adsorbs as an intact disordered layer. Upon heating to 200 K, the IL stays intact, but forms an ordered and well-oriented structure. Upon heating to 250 K, the surface order increases, but at the same time STM and XPS indicate the onset of decomposition. Upon heating to 300 K, decomposition progresses, such that 50-60% of the IL is decomposed. The anion-related reaction products desorb instantaneously, and the cation-related products remain on the surface. Thereby, the surface is partly passivated, enabling the remaining IL to still be adsorbed intact at 300 K. For IL deposition directly at 300 K, a fraction of the IL instantaneously decomposes, with the anion-related products desorbing, opening free space for further deposition of IL. Hence, cation-related species accumulate at the expense of anions, until one fully closed wetting layer is formed. As a consequence, a higher dose is required to reach this coverage at 300 K, compared to 100-200 K.

Greener approach for the separation of naphthenic acid from model oil using Pyrrolidinium-based amino acid ionic liquids

Four novel pyrrolidinium-based amino acid ionic liquids were synthesized and characterized. The physicochemical properties of these amino acid ionic liquids (AAILs), such as viscosity, density, thermal stability, and surface tension were investigated. These ionic liquids (ILs) were used as a green chemistry approach for the extraction of naphthenic acid from the model oil. The influence of amino acid anions on the de-acidification process was assessed by attaching prolinate, glycinate, alaninate and serinate. Extraction results show that very small amounts of ILs are sufficient to extract naphthenic acid from a model oil configuration with a high total acid number. The regeneration and reusability of the synthesized ILs have also been analysed in this work. Moreover, the antimicrobial activity assay was performed to ascertain the potential toxicological effect of the synthesized set on the aquatic system.

Thermoelectric Properties of Conductive Freestanding Films Prepared from PEDOT:PSS Aqueous Dispersion and Ionic Liquids.

In this study, freestanding poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) films modified with an ionic liquid (IL) were synthesized assuming modulization. These films were easily peeled off the glass substrate in water, producing hydrophobic and flexible freestanding films that exhibited extremely high mechanical strengths. The thermoelectric properties of the IL-doped PEDOT:PSS films depended on the amount of IL incorporated. To analyze the mechanism of this dependence in detail, the compositions, higher-order structures, and electronic states of the polymer films were studied by X-ray photoelectron spectroscopy, X-ray diffraction analysis, and electronic absorption spectroscopy. In addition, the carrier density in the polymer film was quantified using electrochemical techniques, and its correlation with the thermoelectric conversion properties was analyzed.

Study of high‐temperature proton exchange membrane through one‐step encapsulation of ionic liquid in sulfonated poly(ether ether ketone)

AbstractThe proton exchange membrane (PEM) is the core component of a high‐performance proton exchange membrane fuel cell (PEMFC). Since the traditional PEM has the disadvantages of poor cell performance and high cost, a new kind of PEM with good proton conductivity, low cost and simple preparation should be explored. In this paper, several different binary hybrid membranes were successfully prepared through one‐step encapsulation of different ionic liquids (ILs) in sulfonated poly(ether ether ketone) (SPEEK). The prepared membranes were characterized by scanning electron microscope (SEM), thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FT‐IR), X‐ray photoelectron spectroscopy (XPS), proton conductivity measurements and dynamic mechanical analysis (DMA). SEM images showed that ILs were fully doped into SPEEK. FT‐IR and XPS proved that SPEEK and IL formed a new chemical bond combined with intermolecular hydrogen bonds. The TG results showed that the binary hybrid membranes could maintain stability even at 300°C. The water uptake and swelling ratio showed that the water absorption capacity of the binary composite membrane played a vital role in improving proton conductivity. The proton conductivity study showed that ILs doping also helped to improve the proton conductivity of the SPEEK membrane. When the doping amount of IL was maintained at 30 wt.%, it has the highest proton conductivity, 25 mS cm−1 at 120°C. It was proved that anhydrous hybrid membrane tetraphenyl imidazole sulfate/SPEEK ([IM2][H2PO4]/SPEEK) could be used in PEMFC at medium temperature.

CO2 Adsorption Performance on Surface-Functionalized Activated Carbon Impregnated with Pyrrolidinium-Based Ionic Liquid

The serious environmental issues associated with CO2 emissions have triggered the search for energy efficient processes and CO2 capture technologies to control the amount of gas released into the atmosphere. One of the suitable techniques is CO2 adsorption using functionalized sorbents. In this study, a functionalized activated carbon (AC) material was developed via the wet impregnation technique. The AC was synthesized from a rubber seed shell (RSS) precursor using chemical activation and was later impregnated with different ratios of [bmpy][Tf2N] ionic liquid (IL). The AC was successfully functionalized with IL as confirmed by FTIR and Raman spectroscopy analyses. Incorporation of IL resulted in a reduction in the surface area and total pore volume of the parent adsorbent. Bare AC showed the largest SBET value of 683 m2/g, while AC functionalized with the maximum amount of IL showed 14 m2/g. A comparative analysis of CO2 adsorption data revealed that CO2 adsorption performance of AC is majorly affected by surface area and a pore-clogging effect. Temperature has a positive impact on the CO2 adsorption capacity of functionalized AC due to better dispersion of IL at higher temperatures. The CO2 adsorption capacity of AC (30) increased from 1.124 mmol/g at 25 °C to 1.714 mmol/g at 40 °C.

Morphology and CO2 adsorption performance of novel ionic liquid microcapsules containing [Bmim][PF6

To solve the contradiction between the high content of ionic liquid (IL) and fast diffusion of CO2 for immobilized IL, this study researched a strategy to optimize the morphology of IL microcapsules by designing different surfactants and methods for improving CO2 adsorption behavior. A series of new IL microcapsules with different morphology were prepared with the aid of 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) as core material, and silica gel or polysulfone (PSF) as shell materials. Then, the characteristics of the microcapsules were assessed via FT-IR spectroscopy, thermogravimetry, morphology, pore structure and CO2/N2 sorption. The results indicated that the morphology and IL loading amount of the microcapsules are significantly affected by the preparation method, the surfactant and carrier material. The obtained samples were micron-scale or even the nanometer scale with good particle dispersibility, meanwhile, the samples prepared by chemical precipitation method with hexadecyl trimethyl ammonium bromide as surfactant has smaller size and more gullies on the surface than the samples prepared by sol-gel method with sodium lignosulfonate as surfactant. The microcapsules prepared by the chemical precipitation and sol-gel methods have about 50 wt%∼70 wt% IL content. While, the sample prepared by the solvent evaporation method displays relatively the lowest IL amount. Moreover, CO2 sorption performance and diffusion, CO2/N2 selectivity and CO2 sorption/desorption cycles of sorbents were further discussed in detail. IL microcapsules with better morphology and higher IL content display excellent CO2 diffusion and sorption selectivity.

Multifunctional CaF2: Yb3+, Ho3+, Gd3+ Nanocrystals: Insight into Crystal Growth and Properties of Upconversion Luminescence, Magnetic, and Temperature Sensing Properties.

The upconversion (UC) emission intensity of Ln3+-doped CaF2 nanomaterials is not ideal, which limits their application in some advanced scientific fields. Hence, it is extremely imperative to enhance the emission intensity of UC nanocrystals. In this work, an ionic-liquid-assisted hydrothermal method based on an ethylene glycol (EG) and ionic liquid (IL) two-phase system was used to synthesize CaF2 doped with Yb3+ and Ho3+. The influence of the amount of IL and the reaction time as well as the concentration of Gd3+ doping on morphology and size was studied in detail, and the growth mechanism was proposed. Green UC luminescence materials were obtained through co-doping Yb3+ and Ho3+ ions. Furthermore, the luminescence of UC was increased monotonically with the introduction of Gd3+ ions. The effect mechanism of Gd3+ doping on the UC luminescence was put forward, which might provide a new method for the promotion of UC luminescence. In addition, the temperature sensing of CaF2: Yb3+/Ho3+/Gd3+ was investigated, which demonstrated that the phosphor has a potential application prospect in thermal sensing. Meanwhile, CaF2: Yb3+/Ho3+/Gd3+ also exhibited a paramagnetic property at room temperature. Therefore, these multifunctional nanocrystals may have prospective applications in optical bioimaging, magnetic resonance imaging, and temperature sensing.

Characteristics and Mechanism of the Adsorption of Imidazole Ionic Liquids in Wastewater by Montmorillonite: Effect of Carbon Chain Length and Dosage of Ionic Liquids

AbstractThis paper studied the adsorption characteristics and mechanism of four kinds of ionic liquids (ILs) with different carbon chain lengths in montmorillonite (Mt). The results of isothermal adsorption at 25 °C show that the adsorption of four kinds of IL in Mt conforms to the Modified‐Langmuir model, and the adsorbance of IL in Mt is positively correlated with the dosage and the carbon chain length of IL. The dynamics research results show that the adsorption of IL in Mt fits well with the quasi‐second‐order dynamics equation. The reaction constant k is negatively correlated with the dosage of IL but positively correlated with the carbon chain length. The thermodynamics results show that the adsorption of IL in Mt is exothermic. The carbon chain length and the dosage of IL have a cross effect on the adsorption capacity of Mt for IL and the structure of the adsorption products. The adsorption capacity of Mt increases first and then decreases with the increase of dosage, and it increases with the increase of carbon chain length. The dosage of IL has little effect on the d(001) of IL/Mt with the short carbon chain, but the d(001) of IL/Mt with the long carbon chain increases with the increase of the dosage of IL. The carbon chain length has little effect on the d(001) of IL/Mt with a low dosage of IL, however, when the dosage of IL is high, the d(001) of IL/Mt increases with the increase of carbon chain length. The specific surface area, pore volume and the most probable radius of IL/Mt decrease with the increase of the dosage and carbon chain length, but excessive amounts of IL will still increase the most probable radius. Molecular dynamics simulation results show that when the dosage of IL is 0.3CEC, four ILs with different carbon chain lengths are arranged in a monolayer between Mt layers, N (N in IL) coordinates with Ot (O on the tetrahedral surface) at a distance of 3.0 Å, and the coordination strength increases with the increase of the carbon chain length of IL.

Absorption of the [bmim][Cl] Ionic Liquid in DMPC Lipid Bilayers across Their Gel, Ripple, and Fluid Phases.

Lipid bilayers are a key component of cell membranes and play a crucial role in life and in bio-nanotechnology. As a result, controlling their physicochemical properties holds the promise of effective therapeutic strategies. Ionic liquids (ILs)—a vast class of complex organic electrolytes—have shown a high degree of affinity with lipid bilayers and can be exploited in this context. However, the chemical physics of IL absorption and partitioning into lipid bilayers is yet to be fully understood. This work focuses on the absorption of the model IL [bmim][Cl] into 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipid bilayers across their gel, ripple, and fluid phases. Here, by small-angle neutron scattering, we show that (i) the IL cations are absorbed in the lipid bilayer in all its thermodynamic phases and (ii) the amount of IL inserted into the lipid phase increased with increasing temperature, changing from three to four IL cations per 10 lipids with increasing temperature from 10 °C in the gel phase to 40 °C in the liquid phase, respectively. An explicative hypothesis, based on the entropy gain coming from the IL hydration water, is presented to explain the observed temperature trend. The ability to control IL absorption with temperature can be used as a handle to tune the effect of ILs on biomembranes and can be exploited in bio-nanotechnological applications.