Immiscible Ionic Liquids Research Articles

Confined Ionic-Liquid-Mediated Cation Diffusion through Layered Membranes for High-Performance Osmotic Energy Conversion.

Ion-selective membranes act as the core components in osmotic energy harvesting, but remain with deficiencies such as low ion selectivity and a tendency to swell. 2D nanofluidic membranes as competitive candidates are still subjected to limited mass transport brought by insufficient wetting and poor stability in water. Here, an ionic-liquid-infused graphene oxide (GO@IL) membrane with ultrafast ion transport ability is reported, and how the confined ionic liquid mediates selective cation diffusion is revealed. The infusion of ionic liquids endows the 2D membrane with excellent mechanical strength, anti-swelling properties, and good stability in aqueous electrolytes. Importantly, immiscible ionic liquids also provide a medium, allowing partial dehydration for ultrafast ion transport. Through molecular dynamics simulation and finite element modeling, that GO nanosheets induce ionic liquids to rearrange, bringing in additional space charges, which can be coupled with GO synergistically, is proved. By mixing 0.5/0.01m NaCl solution, the power density can achieve a record value of ≈6.7W m-2 , outperforming state-of-art GO-based membranes. This work opens up a new route for boosting nanofluidic energy conversion because of the diversity of the ILs and 2D materials.

Stably electrospraying highly conductive sodium chloride aqueous solution coated with outer ionic liquid using coaxial capillary

Concentrated aqueous solutions with high conductivity have been proven difficult to be stably electrosprayed mainly due to their large surface tension, which will easily trigger air discharge. The ionic liquid with lower surface tension is involatile, viscous, and highly conductive and can easily achieve stable electrospray. This paper presents a more convenient method to ionize the concentrated aqueous solution than the previous attempts and proves the feasibility of coaxially electrospraying two highly conductive liquids (∼1 S/m). Our method utilizes a coaxial capillary to coat the highly conducting concentrated sodium chloride (NaCl) aqueous solution (0.67 S/m) with a thin layer of immiscible ionic liquid to form a compound cone and achieve the stable coaxial electrospray. The compound cone remains static at a suitable flow rate (0.1–1 nl/s) of the ionic liquid. At a higher or lower flow rate, the compound cone elongates or shrinks and eventually vibrates. Due to the high conductivity of both liquids, the spray current does not follow the current scaling law. The spray current is mostly dominated by the NaCl solution and counterintuitively decreases as the flow rate of the ionic liquid increases due to the frequent vibration of the compound cone. The highly conducting thin layer of the ionic liquid is the key to achieving stable coaxial electrospray. It lowers the surface tension of the compound cone and shields the external electric field acting at the inner aqueous solution; thus, the air discharge of the aqueous solution is suppressed, and the stable compound cone can be formed.

A novel aqueous Li4Fe(CN)6 cathode and hydrophobic ionic liquid electrolyte combined lithium-ion battery

Present study reports an easy and cost-effective method of synthesis of Li4Fe(CN)6 cathode from K4Fe(CN)6.3H2O and LiClO4 in aqueous medium for its use in lithium-ion battery. The synthesized Li4Fe(CN)6 is characterized by UV-Vis, FTIR and cyclic-voltammetry studies. A special laboratory model lithium-ion battery is designed, where aqueous Li4Fe(CN)6 solution acts as a cathode, metallic lithium as anode and 1 molar solution of LiPF6 dissolved in water immiscible ionic liquid, 1-Butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6) as electrolyte. The cell exhibits an open circuit potential of 3.12 volt and a good charge-discharge cycling behaviour. The cell delivered a maximum discharge capacity of 86 mAhg-1 (theoretical capacity 112 mAhg-1) at 0.2 C rates with an average discharge potential of 2.1 volts. Although the ionic liquid is a little bit cost intensive, but the easy synthesis methodology with the cheapest raw materials and overall cycling efficiency, makes this technology available as a green economical energy storage device in the current battery industry. Copyright © 2017 VBRI Press.

Removing Simultaneously Sulfur and Nitrogen from Fuel under a Sustainable Oxidative Catalytic System

An effective process to remove nitrogen-based compounds from fossil fuels without harming the process of sulfur removal is an actual gap in refineries. A success combination of desulfurization and denitrogenation processes capable of completely removing the most environmental contaminates in diesel under sustainable conditions was achieved in this work, applying polyoxometalates as catalysts, hydrogen peroxide as oxidant, and an immiscible ionic liquid as an extraction solvent. The developed process based in simultaneous oxidative desulfurization (ODS) and oxidative denitrogenation (ODN) involved initial extraction of sulfur and nitrogen compounds followed by catalytic oxidation. Keggin-type polyoxomolybdates revealed much higher reusing capacity than the related polyoxotungstate. Effectively, the first catalysts practically allowed complete sulfur and nitrogen removal only in 1 h of reaction and for ten consecutive cycles, maintaining the original catalyst and ionic liquid samples.

Pre-deposited Co nanofilms promoting high alloying degree of PdxAu nanoparticles as electrocatalysts in alkaline media

High alloyed and well dispersed PdxAu nanoparticles are deposited on pre-deposited Co nanofilm substrates (PdxAu/Co-nanofilms/C) by using an immiscible ionic liquid (IL)/water interface. However, low alloyed PdxAu/C catalysts are formed without pre-deposited Co nanofilms through the same synthesis method. The high-alloyed PdxAu/Co-nanofilms/C catalysts demonstrate significantly increased activity for ethanol oxidation reaction (EOR) than low-alloyed PdxAu/C of the same Pd/Au composition, with the catalysts of low Pd/Au atom ratio (Pd:Au = 1:1) demonstrating the optimal activity. Notably, high alloyed degree of the PdxAu nanoparticles in the PdxAu/Co-nanofilms/C catalysts brings the lattice expansion of Pd, causing an up-shift of the d-band center, which results in the enhancement of OH− adsorption and correspondingly promotes electro-oxidation of ethanol excluding the effect of Co nanofilm substrates. Differently, the enhancement activities of the Pd-Au bimetallic system for oxygen reduction reaction (ORR) are almost not affected by the alloying degree and only dependent on Pd/Au atom ratios, with the catalysts of low Pd/Au atom ratio (Pd:Au = 1:1) displaying the highest ORR mass activity, respectively. These results exhibit the specific dependence between the different electrochemical process and the physical parameters for the Pd-Au bimetallic system.

Membraneless energy conversion and storage using immiscible electrolyte solutions

Breakthrough alternative technologies are urgently required to alleviate the critical need to decarbonise our energy supply. We showcase non-conventional approaches to battery and solar energy conversion and storage (ECS) system designs that harness key attributes of immiscible electrolyte solutions, especially the membraneless separation of redox active species and ability to electrify certain liquid–liquid interfaces. We critically evaluate the recent development of membraneless redox flow batteries based on biphasic systems, where one redox couple is confined to an immiscible ionic liquid or organic solvent phase, and the other couple to an aqueous phase. Common to all solar ECS devices are the abilities to harvest light, leading to photo-induced charge carrier separation, and separate the products of the photo-reaction, minimising recombination. We summarise recent progress towards achieving this accepted solar ECS design using immiscible electrolyte solutions in photo-ionic cells, to generate redox fuels, and biphasic “batch” water splitting, to generate solar fuels.

Comparative evaluation of extraction of tetra- and hexa-valent neptunium ions by CMPO in a room temperature ionic liquid

ABSTRACT Solvent extraction studies were performed to understand the extraction behavior of Np4+ and NpO2 2+ from acidic feeds with CMPO (octyl (phenyl)-N,N-diisobutyl carbamoyl methyl phosphine oxide) dissolved in 1-butyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide, a water immiscible ionic liquid. Slope analyses on the distribution data revealed the extraction of ML2 type species, where M = Np4+ or NpO2 2+, and L = CMPO. Studies were also carried out with Pu4+ and UO2 2+ under identical conditions. The nature of the extracted species was found to vary with the nature of the ionic species.

Nanochannel-Based Transport in an Interfacial Memristor Can Emulate the Analog Weight Modulation of Synapses.

By exploiting novel transport phenomena such as ion selectivity at the nanoscale, it has been shown that nanochannel systems can exhibit electrically controllable conductance, suggesting their potential use in neuromorphic devices. However, several critical features of biological synapses, particularly their conductance modulation, which is both memorable and gradual, have rarely been reported in these types of systems due to the fast flow property of typical inorganic electrolytes. In this work, we demonstrate that electrically manipulating the nanochannel conductance can result in nonvolatile conductance tuning capable of mimicking the analog behavior of synapses by introducing a room-temperature ionic liquid (IL) and a KCl solution into the two ends of a nanochannel system. The gradual conductance-tuning mechanism is identified through fluorescence measurements as the voltage-induced movement of the interface between the immiscible IL and KCl solution, while the successful memorization of the conductance tuning is ascribed to the large viscosity of the IL. We applied a nanochannel-based synapse to a handwritten digit-recognition task, reaching an accuracy of 94%. These promising results provide important guidance for the future design of nanochannel-based neuromorphic devices and the manipulation of nanochannel transport for computing.

Heteropoly acids-functionalized Janus particles as catalytic emulsifier for heterogeneous acylation in flow ionic liquid-in-oil Pickering emulsion

In this work, we developed a continuous non-aqueous flow Pickering emulsion interface catalysis (FPIC) system for heterogeneous acylation. Poly (1-vinyl-3-ethylimidazolium bromide) (PILs) functionalized silica@PS/PDVB Janus particles (JPs) were synthesized. The catalyst H3PW12O40 (PA) was then immobilized on PIL-modified JPs by anion-exchanging. The PIL grafted on the silica side and the inherent oleophilic phenyl groups on the other side endow the Janus particle with excellent amphipathy for the immiscible ionic liquid (IL) [BMIM]BF4 and toluene. Therefore, emulsification and catalytic capability were realized simultaneously on the PA-PILs-JPs. The FPIC column system for acylation reaction was accomplished by packing the IL-in-oil Pickering emulsion into a column reactor, and exhibited excellent catalytic performance, high stability during the reaction process as well as remarkable recyclability.

Oxygen Reduction Activity and Stability of Composite Pdx/Co-Nanofilms/C Electrocatalysts in Acid and Alkaline Media.

The morphology tuning of Pd and Pd-M nanoparticles is one of the significant strategies to control the catalytic activity toward oxygen reduction reaction (ORR). In this study, composite Pdx/Co-nanofilms/C electrocatalysts of Pd nanoparticles implanted onto Co nanofilms were synthesized on an immiscible ionic liquid (IL)/water interface for ORR. The Pd nanoparticles implanted onto Co nanofilms show a marked distortion of crystal lattice and surface roughness. These Pdx/Co-nanofilms/C electrocatalysts exhibit enhanced activity for ORR compared with Pd/C and PdxCo/C catalysts in both acid and alkaline solutions, in which the Pd3/Co-nanofilms/C catalyst displays the highest ORR mass activity. The superior ORR mass activities of the fabricated Pdx/Co-nanofilms/C catalysts may be mainly attributed to their larger catalytic areas, which are conferred by the rough surface of Pd nanoparticles with a distorted crystal lattice, and the synergistic effect between the surface Pd atoms and the 2D Co nanofilm substrate. The relationship between ORR mass activity and Pd/Co atom ratio varies in different electrolytes. Furthermore, by using proper heat-treatment methods, the Pdx/Co-nanofilms/C catalysts exhibit improved cycling stability compared with pure Pd/C catalyst after extended potential cycling.

Frontiers of low-carbon technologies: Results from bibliographic coupling with sliding window

Abstract It is of great significance to quickly and accurately detect the current and future development trends of low-carbon technologies (LCT). However, there is a lack of detecting research fronts of low-carbon technologies based on the bibliographic data. This paper proposes a research framework integrating LCT domains and the bibliometric coupling with sliding window technique to explore the LCT research fronts in recent decade (from 2007 to 2016). Eleven research fronts matching the foresight given by LCT experts are identified, including carbon capture and storage (CCS) in power generation, technology transfer, technology diffusion, electrocoagulation, magnetic nanoparticles, critical metals application, electrocatalytic water oxidation, ionic liquids, mutually immiscible ionic liquids, electric vehicle (China), electric vehicle (UK and USA). Closer investigation of the evolution shows that CCS application in the power plants and hydrogen production from water electrolysis are two emerging fronts. Besides, bibliometric coupling with sliding window is an effective tool to detect the frontiers of low-carbon technologies. Finally, the implications of the research for LCT monitoring and development are discussed.

Immiscible dual ionic liquid-ionic liquid mineral separation of rare-earth minerals

Abstract The potential of ionic liquid-ionic liquid mineral separation process as a novel ionic liquid-based system to beneficiate rare earth element (REE) bearing minerals was investigated. This multiphase beneficiation system was prepared using two mutually immiscible ionic liquids (IL) as dispersed and continuous phases. A phosphonium/ammonium based ionic liquid as droplet phase and three different ionic liquids as continuous phase were applied to evaluate this approach of beneficiation of REE complex ore. Ionic liquid-ionic liquid mineral separation tests were performed on an actual rare earth complex ore with its main composing minerals consisting of monazite, bastnasite, ankerite, calcite and dolomite. Fourier Transform Infrared (FTIR) spectroscopy, Atomic Force Microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS) analyses were performed to unveil the nature of interactions between IL droplet phase and each of the minerals composing the ore. Bastnasite and monazite have been found to exhibit stronger chemisorption interactions with phosphonium/ammonium based ionic liquid in comparison with calcite, ankerite and dolomite. Density Functional Theory (DFT) simulations were also conducted to reveal the configuration of ionic liquid moieties on the surface of the minerals through ionic liquid adsorption. It was found that the IL anionic moiety directly interacts with the metal cations on the mineral surfaces through covalent bonds, at the expense of the cationic moiety which is only involved in weaker solvophobic interactions. DFT simulation also indicated that the adsorption geometry of IL is based on cis-conformation where the cationic and anionic moieties adsorb next to each other on the mineral surfaces.

Experimental study of ionic liquid-water flow in T-shaped microchannels with different aspect ratios

Flow regimes of immiscible ionic liquid - water flow in T-shaped microchannels with 160 um hydraulic diameter and 1:2 and 1:4 aspect ratios are experimentally studied in the present work. Plug length and velocity were measured using high-speed visualization of the flow. Flow pattern maps were drawn for two channels. Parallel flow was shown to prevail for 1:4 aspect ratio channel in comparison to 1:2.

Liquid-liquid equilibria of mutually immiscible ionic liquids with a common anion of basic character

Pairs of ionic liquids with the chloride or acetate anion as common ion and with largely different cations (namely a 1-alkyl-3-methylimidazolium cation and either methyltrioctylammonium or trihexyl(tetradecyl)phosphonium) were selected to investigate their mutual miscibility. Most of the pairs investigated were found to give rise to biphasic, non-volatile, totally liquid systems over wide temperature and composition ranges. An accurate determination of the liquid-liquid equilibria was carried out as a function of temperature, finding LCST-like behaviours for the systems with the phosphonium cation, and hourglass-shaped liquid-liquid domains for the systems with the ammonium cation. Enthalpies and entropies of mixing, calculated from the liquid-liquid equilibrium values, revealed that the first type of liquid-liquid equilibria was entropically driven, whereas for the second type a transition from enthalpically to entropically driven occurred with an increase in temperature.

Efficient antimicrobial activity and reduced toxicity of 1-dodecyl-3-methylimidazolium tetrafluoroborate ionic liquid/β-cyclodextrin complex

Water immiscible ionic liquid 1-dodecyl-3-methylimidazolium tetrafluoroborate (DMIM-BF4) and its inclusion complex with β-cyclodextrin (β-CD) in molar ratio 1:1 have been synthesized. The formation of DMIM-BF4/β-CD complex was confirmed by FT-IR analysis, 1H NMR analysis, and differential scanning calorimetry data. Our results indicate that the aliphatic tail of DMIM-BF4 is included into β-CD inner cavity whereas imidazolium ring is located outside the torus. Moreover, the weak interaction between polar components of ionic liquid and hydrophilic outer surface of β-CD has also been detected. The standard agar disk diffusion method was performed to evaluate antimicrobial efficiency of the obtained compounds against Staphylococcus aureus (ATCC-25923), Escherichia coli (ATCC-25922) and Pseudomonas aeruginosa (ATCC-27853), Candida albicans (M 885 ATCC 10231) and its clinical isolate test-cultures. It has been found that both DMIM-BF4 and DMIM-BF4/β-CD complex possess high antimicrobial activity as revealed by similar zone inhibition values against all tested microorganisms. The acute toxicity studies on Danio rerio (zebrafish) model organism showed that the pure ionic liquid DMIM-BF4 is slightly toxic compound having LD50 value of 7mg/L, whereas DMIM-BF4/β-CD complex has considerably reduced toxicity (LD50=100mg/L) and therefore have potentially wider application areas.

In situ emulsification microextraction using a dicationic ionic liquid followed by magnetic assisted physisorption for determination of lead prior to micro-sampling flame atomic absorption spectrometry

For the first time, a simple and efficient in situ emulsification microextraction method using a dicationic ionic liquid followed by magnetic assisted physisorption was presented to determine trace amounts of lead. In this method, 400 μL of 1.0 mol L−1 lithium bis (trifluoromethylsulfonyl) imide aqueous solution, Li[NTf2], was added into the sample solution containing 100 μL of 1.0 mol L−1 1,3-(propyl-1,3-diyl) bis (3-methylimidazolium) chloride, [pbmim]Cl2, to form a water immiscible ionic liquid, [pbmim][NTf2]2. This new in situ formed dicationic ionic liquid was applied as the acceptor phase to extract the lead-ammonium pyrrolidinedithiocarbamate (Pb-APDC) complexes from the sample solution. Subsequently, 30 mg of Fe3O4 magnetic nanoparticles (MNPs) were added into the sample solution to collect the fine droplets of [pbmim][NTf2]2, physisorptively. Finally, MNPs were eluted by acetonitrile, separated by an external magnetic field and the obtained eluent was subjected to micro-sampling flame atomic absorption spectrometry (FAAS) for further analysis. Comparing with other microextraction methods, no special devices and centrifugation step are required. Parameters influencing the extraction efficiency such as extraction time, pH, concentration of chelating agent, amount of MNPs and coexisting interferences were studied. Under the optimized conditions, this method showed high extraction recovery of 93% with low LOD of 0.7 μg L−1. Good linearity was obtained in the range of 2.5–150 μg L−1 with determination coefficient (r2) of 0.9921. Relative standard deviation (RSD%) for seven repeated measurements at the concentration of 10 μg L−1 was 4.1%. Finally, this method was successfully applied for determination of lead in some water and plant samples.

Fabrication of “clean” nano-structured metal materials on ionic liquid/water interface

Transition metal Co, noble metal Pd and Pd2Co alloy nano-structured materials were fabricated on the immiscible ionic liquid (IL)/water interface with KBH4 as the reducing agent. The Co formed “clean” Co nano-films with a thickness of 1–2nm on the IL/water interface displayed no adsorption of IL on Co films with the edge of Co nano-films curled to nano-tubes. However, the Pd and Pd2Co nanoparticles were picked up by IL from the aqueous phase forming a sphere-shaped structure, which exhibited the regular face-centered cubic (FCC) crystalline characteristic. Infrared (IR) spectra indicated a weak adsorption between the ionic liquid and the Pd and Pd2Co alloy nanoparticles. Applying ionic liquids as the immiscible solvent in the IL/aqueous system can yield “clean” nano-structured materials with controlled nano-structure on the IL/water interface as a result of the selective adsorption of the ionic liquid on the metal and the resulting template effects.

Separation of rare earths and nickel by solvent extraction with two mutually immiscible ionic liquids

Download options Please wait... Article information DOI https://doi.org/10.1039/C3RA46261G Article type Paper Submitted 04 Aug 2013 Accepted 11 Nov 2013 First published 14 Nov 2013 Download Citation RSC Adv., 2014,4, 5753-5758 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions Separation of rare earths and nickel by solvent extraction with two mutually immiscible ionic liquids A. Rout, S. Wellens and K. Binnemans, RSC Adv., 2014, 4, 5753 DOI: 10.1039/C3RA46261G To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Social activity Tweet Share Search articles by author Alok Rout Sil Wellens Koen Binnemans

Antimicrobial properties and thermal stability of polycarbonate modified with 1‐alkyl‐3‐methylimidazolium tetrafluoroborate ionic liquids

ABSTRACTFour water immiscible ionic liquids (ILs): 1‐hexyl‐3‐methylimidazolium tetrafluoroborate, 1‐heptyl‐3‐methylimidazolium tetrafluoroborate, 1‐octyl‐3‐methylimidazolium tetrafluoroborate and 1‐dodecyl‐3‐methylimidazolium tetrafluoroborate have been synthesized. Polycarbonate (PC) films containing ILs were prepared by solvent casting from methylene chloride solutions. Scanning electron microscopy measurements showed the high homogeneity of PC/IL films with the IL content up to 4 wt %. The tendency to IL aggregation was observed for polymeric films with higher IL content (5%). PC/IL composites were found to have the reduced thermal decomposition temperature under both an air and a nitrogen atmosphere in comparison with the neat PC. The effect of IL content on the antimicrobial activity of PC films against Escherichia coli bacteria was studied. Pronounced antimicrobial efficacy was revealed for PC/IL films for all studied ILs starting from 3 wt % of IL. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40050.

Enhanced stability of ruthenium complex in ionic liquid doped electrospun fibers

Utilization of electrospun polymer fibers for optical gas sensing purposes results with many advantages such as increasing in surface area, sensitivity and an enhancement in all sensor dynamics. In this study, oxygen sensitive fibers of polymethyl methacrylate and ethyl cellulose were fabricated by electrospinning technique. We utilized water miscible and immiscible ionic liquids, and perfluoro compounds as additives. Steady state and lifetime based spectral response of the fluorescent tris(2,2′-bipyridyl)ruthenium(II)chloride (Ru(bipy)32+) was measured as analytical signal in the absence and presence of the gaseous oxygen. The method can only be applied for gas samples. The stability of the Ru dye in the employed matrix materials was superior to the previously reported ones and when stored at the ambient air of the laboratory there was no significant drift in intensity after 44 months. Our stability tests are still in progress.