Ternary Deep Eutectic Solvent Research Articles

Characterization of Thermoplastic Starch Plasticized with Ternary Urea-Polyols Deep Eutectic Solvent with Two Selected Fillers: Microcrystalline Cellulose and Montmorillonite

The aim of the study was to prepare and characterize composite materials based on thermoplastic starch (TPS)/deep eutectic solvent (DES). Potato starch was plasticized with ternary DES: urea:glycerol:sorbitol and modified with the selected fillers: microcrystalline cellulose and sodium montmorillonite. Films were prepared via twin-screw extrusion and thermocompression of the extrudates. Then, the physicochemical properties of the TPS films were examined. The ternary DES effectively plasticized the polysaccharide leading to a highly amorphous structure of the TPS (confirmed via mechanical tests, DMTA and XRD analyses). An investigation of the behavior in water (swelling and dissolution degree) and water vapor transmission rate of the films was determined. The introduction of the two types of fillers resulted in higher tensile strength and better barrier properties of the composite TPS films. However, montmorillonite addition exhibited a higher impact than microcrystalline cellulose. Moreover, a cone calorimetry analysis of the TPS materials revealed that they showed better fire-retardant properties than TPS plasticized with a conventional plasticizer (glycerol).

One-Step Rapid Conversion of Electroactive CoMnO Nanostructures Using a Deep Eutectic Solvent as the Template, Solvent, and Source

Here, a ternary deep eutectic solvent (DES) is employed as the reaction medium, reducing agent, template, and source for the preparation of cobalt manganese oxide (CoMnO) at room temperature. The hydrogen-bonding interaction between DES and manganese precursors resulted in a rapid conversion of CoMnO nanostructures, and the process was well controlled with the addition of water, which eventually reduced the bonding interaction between the formed nanostructures. The reaction between DES and potassium permanganate is carried out at different time intervals (1, 10, 30, 45, 60 min, 1.5, 2, 4, and 12 h) before the addition of water. With varying reaction times, the morphology, pore structure, surface area, and electrochemical properties of the synthesized CoMnO structures also vary. The highest specific capacitance of 242 F g–1 at 0.1 A g–1 is accomplished using CoMnO nanostructures, where KMnO4 and ternary DES reacted for 4 h. The CoMnO nanostructures prepared by the DES route also show excellent electrochemical stability with 97% initial capacitance retention at 10 A g–1 over 10 000 charge/discharge cycles. Further, the CoMnO-60 min sample shows outstanding electrochemical OER activity with 300 mV overpotential to obtain a current density of 10 mA cm–2 and a Tafel slope value of 73 mV dec–1.

Quasi-solid-state supercapacitors based on wide-temperature eutectogels

Carbon-based supercapacitors possess fast charge-discharge rate, superior power density, and excellent cyclic lifespan, but it is subject to some problems, such as low operating potential window and energy density. To address these issues, a ternary deep eutectic solvent with a freezing point below −85.6 °C was firstly prepared using lithium perchlorate trihydrate and urea and then used as a reaction solvent to take part in a free radical polymerization reaction to prepare eutectogels. The optimized eutectogel showed an ionic conductivity of 20 mS cm−1 at room temperature and could be still stretched and twisted even at −40 °C. The quasi-solid-state supercapacitor composed of a eutectogel and carbon electrodes demonstrated a stable voltage window of 0–2.0 V, an energy density of 10.76 Wh kg−1 at a power density of 465 W kg−1 and excellent cycling stability with ∼105 % capacitance retention after 10,000 cycles. The flexible quasi-solid-state supercapacitors with such a eutectogel not only could be operated from −40 to 60 °C, but also exhibited a moderate bendability. Moreover, the damaged flexible quasi-solid-state supercapacitor could be still charged and drive a mini-fan for ⁓60 s. Therefore, the eutectogels displayed a promising potential for enhancing the energy density of carbon-based supercapacitors and should also provide instructive guidance for the preparation of wide-temperature gel polymer electrolytes.

Facile sulfation of cellulose via recyclable ternary deep eutectic solvents for low-cost cellulose nanofibril preparation.

Here we present a new method to treat cellulose with a sulfamic acid-urea-choline chloride (ternary deep eutectic solvent) system, which can realize both swelling and sulfation of cellulose. This can greatly reduce the energy consumption in the process of cellulose nanoization, and use it to successfully prepare food packaging films for eliminating odors. We hope that due its simplicity and resource-efficiency, this method will have a widespread influence on currently used (nano) cellulose modification protocols.

High-purity lignin from selective biomass fractionation with ternary deep eutectic solvents

Green and recyclable ternary deep eutectic solvent was developed to selectively extract lignin of high purity, desirable molecular weight and monomeric yield for applications in reinforcement materials and bio-oil was produced from biomass.

A novel ternary deep eutectic solvent pretreatment for the efficient separation and conversion of high-quality gutta-percha, value-added lignin and monosaccharide from Eucommia ulmoides seed shells

A novel ternary deep eutectic solvent (DES), consisted of choline chloride, oxalic acid and ethylene glycol, was developed as a green, low-cost and recyclable pretreatment system for multi-stage utilization of Eucommia ulmoides seed shells. Under optimum conditions, 79.7 % hemicellulose and 65.6 % lignin were quickly removed while 84.0 % cellulose was retained. After DES pretreatment, the yield and purity of gutta-percha achieved 85.1 mg/g and 96.2 %, which increased 1.4 and 1.8 folds higher than that of un-treatment ones. Meanwhile, 69.1 % enzymatic digestibility of cellulose was obtained, that was 2.3 folds higher than that of raw substrates. Moreover, 53.6 % low-condensation lignin with aromatic structures and valuable aryl-ether linkages was well collected. Importantly, the DES that has been recycled five runs can still remove 73.9 % hemicellulose and 58.0 % lignin. Overall, the DES was determined to efficiently promote the separation and conversion of high-quality gutta-percha, value-added lignin and high-yield glucose from Eucommia ulmoides seed shells.

Biomimetic catalytic aerobic oxidative desulfurization of diesel with NHPI-based ternary deep eutectic solvents

It is a challenging issue to achieve efficient aerobic oxidation desulfurization (AODS) under mild conditions. Inspired by respiratory chain system, a metal-free biomimetic system was developed in this paper with a functionalized ternary deep eutectic solvent (DES) containing N-hydroxyphthalimide (NHPI), p-toluene sulfonic acid (p-TsOH), and polyethylene glycol (PEG) for deep oxidative desulfurization. It was found that the NHPI/5PEG4000/p-TsOH system exhibited an outstanding desulfurization activity, and the removal of dibenzothiophene (DBT) reached 100% within 5 h at 80 οC. Significantly, it is the first attempt to use a DES as an extraction agent, reaction medium, catalyst, and electron transfer mediator (ETM) simultaneously. Mechanistic studies revealed that NHPI demonstrated a dual function: namely, producing the PINO radical to initiate the reaction, and acting as an ETM in biomimetic systems to promote the activation of oxygen molecules, thereby finely improving the AODS performance of the acidic DESs. These findings regarding the aforementioned biomimetic oxygen activation mechanism of the NHPI-based ternary DES for AODS provide a novel insight into the construction of biomimetic system in the future.

Development of salt-induced homogenous liquid-liquid extraction based on ternary deep eutectic solvent coupled with dispersive liquid-liquid microextraction for the determination of heavy metals in honey

In this work, a homogenous liquid–liquid extraction method was combined with dispersive liquid–liquid microextraction and utilized for the extraction of Co, Zn, Ni, Cu, Pb, and Tl from honey samples before their determination by inductively coupled plasma-atomic emission spectrometry. For this purpose, firstly, diluted honey solution was transferred into a glass test tube and mixed with a few milliliters of a mixture of n-butanol and choline chloride: menthol: p-aminophenol deep eutectic solvent. A homogenous solution was obtained. After that an appropriate amount of sodium chloride was added into the solution and sonicated for 6 min. During this step, the homogenous solution was broken and the mixture of n-butanol and the deep eutectic solvent mixture was collected on top of the solution. The supernatant phase was removed and quickly injected into deionized water. After centrifugation, the collected phase at the bottom of the tube was injected into the determination system. Under the optimum situations, low limits of detection (0.24–0.74 ng g–1) and quantification (0.79–2.46 ng g–1), high extraction recoveries (80–92%), and good repeatability (relative standard deviations equal to or less than 3.6% and 3.9% for intra– and inter-day precisions, respectively) were acquired. Finally, the offered method was employed for determination of the studied heavy metals in various honey samples marketed in Tabriz city, Iran.

Mix-and-Match Diols: Adjusting Self-Assembly of Micellar Phases in Choline Chloride Eutectics

The common Deep Eutectic Solvent (DES) ‘ethaline’ (1:2 choline chloride:ethylene glycol) was examined here as a basis for the self-assembly of the surfactant dodecyltrimethylammonium bromide (C12TAB). A phase diagram was constructed, showing evidence for a L1 (micellar) phase, confirmed by tensiometry to have a room temperature critical micelle concentration (CMC) of 1.2 wt.%. Small angle neutron scattering (SANS) measurements indicate formation of interacting globular micelles with slightly smaller apparent radii than in water. The apparent mesophase/multiphase region was studied using SWAXS, demonstrating rich mesoscopic lyotropic liquid crystalline phase behaviour, with evidence for lamellar Lα peaks, alongside potential co-crystalline phases. We attempted to tailor the self-assembly by studying binary DES containing longer diols including 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, and 1,5-pentanediol, and ternary DES where the HBD component was a 1:1 ethylene glycol:diol mixture. However, synchrotron SAXS showed that only ternary ‘propethaline’ mixtures displayed signs of self-assembly and micellization, perhaps due to the reduction in calculated Gordon parameter, which decreases linearly with increasing alkyl chain length. Systematic differences were thus observed in the ability of the solvents to modulate assembly, from globular micelles in ChCl:EG, to weaker assembly in long-tail DES, and complete solubilisation in butaline and pentaline.

Multimode ultrasound and ternary deep eutectic solvent sequential pretreatments enhanced the enzymatic saccharification of corncob biomass

Corncob (CB) is a valuable agricultural waste in high abundance. It is mainly composed of cellulose, hemicellulose and lignin that link in a complex interlocking matrix. The key to its utilization depends on separating cellulose from lignin and hemicellulose using an environment-friendly and effective pretreatment method to improve glucose yield. The study aimed to investigate the effect of sequential pretreatment of CB with ultrasound (US) in conjunction with ternary deep eutectic solvent (TDES). The US, type and molar ratio of TDES, temperature, and time were optimized. The results showed that under the optimum conditions, US (40 +60 kHz, 60 min) + TDES (ChCl-Gly-LA, 1:1:2, 120 ℃, 3 h), the removal of lignin and hemicellulose were 87.54 % and 67.00 %, respectively, and the recovery of cellulose was 82.18 %. After 72 h of enzymatic hydrolysis , the yield of glucose and xylose were 76.94 % and 41.26 %, respectively. Comparatively, pretreated CB yielded 61.58 % glucose and 26.90 % xylose higher than the untreated. Scanning electron microscopy revealed that the surface of the CB became cracked and rugged. X-ray diffraction showed that the CrI increased significantly from 36 % to 59 %. Fourier transform mid-infrared spectroscopy indicated significant changes in the characteristic functional groups of lignin and hemicellulose. Increases in Tonset, Tendset, Tp, Vmax and decreases in Char at 600 °C all corresponded to increases in thermal stability. These results further confirmed that TDES combined with ultrasonic pretreatment effectively removed lignin and hemicellulose. In conclusion, this approach could greenly and efficiently pretreat CB as a new method for biomass pretreatment. • Double hydrogen bond acceptor (donor) ternary pretreatment DES was studied. • The lignin removal efficiency of ternary DES was higher than binary DES. • TDES containing lactic acid reduced significantly the lignin content. • TDES combined with ultrasonic pretreatment increased lignin removal rate. • TDES combined with ultrasonic pretreatment enhanced sugar yields.

Freeze-resistant, rapidly polymerizable, ionic conductive hydrogel induced by Deep Eutectic Solvent (DES) after lignocellulose pretreatment for flexible sensors

In this paper, ternary DES (choline chloride, glycerol, Lewis acid) was used to pretreat lignocellulose, and the DES solution with dissolved lignin was utilized as the medium of hydrogel to prepare DES-based polyacrylic acid/polyvinyl alcohol (PAA/PVA) double network hydrogels with great mechanical properties, self-adhesion, and high electrochemical sensitivity. The entanglement of PAA with PVA chains, the covalent linkage between Al3+ and PAA chains and the metal phenol network (MPN) formed by Al3+ and lignin improved the mechanical properties of the hydrogels, enabling the prepared hydrogels to achieve a tensile strain of 400 % and an elongation at break of 150 kPa. Secondly, the introduction of DES solution endowed the hydrogel with excellent electrical sensing ability and anti-freezing property, so that the hydrogel still maintains good flexibility and ionic conductivity at −20 °C. It was also found that the above hydrogel can achieve a high gauge factor of 4.19 as a flexible sensor, which provides scientific ideas for the application of the pretreated DES solution in the field of flexible wearable.

Preparation, characterization of light-colored lignin from corn stover by new ternary deep eutectic solvent extraction

The industrial lignin has shown great potential to replace some of petrochemical. But the deep color of lignin limits their application in high-value field. The extraction of light-colored lignin from lignocellulose still remains challenging. Here, we reported a strategy for rapid extraction of lignin from corn stover by using a new ternary deep eutectic solvent (TDES) composed of choline chloride (ChCl), formic acid (FA) and maleic acid (MA). The color feature and structural characterization of obtained lignin was comprehensively elucidated. The results revealed that the lignin streams had light color (brightness ISO 23.44 %) with a high yield (76.3 %), purity (93.5 %), low molecular weight (Mw 1544–2040 g/mol), and low polydispersity (PDI ≤ 1.76). The introduction of MA could reduce the destruction of lignin substructure during the treatment process and avoid the deepening of lignin color. Quantitative analysis of conjugated carbonyl and quinone carbonyl and semi-quantitative analysis of lignin by 2D NMR showed that temperature had a great influence on its structure.

Poly(methylene blue)-ternary deep eutectic solvent/Au nanoparticle modified electrodes as novel electrochemical sensors: Optimization, characterization and application

A new electrochemical sensor based on a nanocomposite formed by the electroactive redox polymer poly(methylene blue) (PMB) formed in a ternary deep eutectic solvent (DES) mixture, and gold nanoparticles (AuNP) was developed. The polymerisation of MB was carried out by potential cycling in ternary DES formed by choline chloride, ethylene glycol and fructose, containing 84% of the choline chloride: ethylene glycol mixture, in the presence of an acid dopant. The composition of the AuNP-chitosan dispersion was optimized by studying the effect of different concentrations of the nanoparticles and the polymer in the dispersion on the PMB film growth. The nanocomposite films obtained under different conditions were characterized by cyclic voltammetry, electrochemical impedance spectroscopy and scanning electron microscopy. The nanocomposite with the best characteristics was also obtained in aqueous media for comparison. The nanocomposite-based sensor formed by AuNP and PMB in DES was used for determining ascorbic acid (AA) and 5-aminosalicylic acid (5-ASA) by fixed potential amperometry at +0.20 V in 0.10 mol L−1 KCl and at +0.40 V in Britton-Robinson buffer at pH 7, respectively. Limits of detection of 0.40 μmol L−1 and 0.064 μmol L−1 were obtained for AA and 5-ASA, respectively, with the PMBDES/AuNP/GCE. The sensor was successfully applied to determine both analytes in pharmaceutical samples.

Electrochemical Sensing of Nitrofurazone and Semicarbazide on an Au-Ag Film Fabricating from a Deep Eutectic Solvent

A facile electrochemical sensor is reported for the highly selective and sensitive detection of nitrofurazone (NFZ) and its metabolites, semicarbazide (SC), by using an Au-Ag modified electrode. The Au-Ag film was produced on a Cu foil by electrodeposition in a choline chloride-urea-glycerol ternary deep eutectic solvent containing gold (III) ions and silver (I) ions. Cyclic voltammetry (CV) indicates that the co-deposition of Au-Ag would be feasible. The morphology, crystallinity, and composition of Au-Ag deposits were characterized via scanning electron microscopy (SEM), powder X-ray diffractometer, and X-ray photoelectron spectroscopy (XPS). Under the optimal condition, the Au-Ag modified electrode shows a wider linear concentration range of 1.99–643.49 μM with a low detection limit of 0.2 μM for NFZ. The corresponding linear range of SC is 7.94 to 482 μM, and the detection limit is 1.01 μM. It also demonstrated good anti-interference ability against various common interfering substances. Finally, the modified electrode was successfully applied in the real samples, and the average recoveries for NFZ and SC were 100.59% and 101.01%, respectively. The present electrochemical strategy is promising to broaden the practical electrochemical application in the environment.

A novel ternary deep eutectic solvent for efficient recovery of critical metals from spent lithium-ion batteries under mild conditions

In terms of environmental pollution and the shortage of resources, an efficient recovery of valuable metals in spent lithium-ion batteries (LIBs) is currently the most promising measure to achieve green sustainability of cathode materials. In this study, an choline chloride (ChCl)/ benzenesulfonic acid (BSA)/ ethanol ternary deep eutectic solvent (e.g., ChCl:BSA:Ethanol = 1:1:2 in molar ratio) was designed and applied to efficiently leach lithium (Li) and cobalt (Co) from spent LIBs under mild conditions. The experimental results show that the leaching efficiencies of Li and Co can reach 99% and 98%, respectively, under the optimal conditions: (i) a reaction temperature of 90 °C, (ii) a Solid/Liquid ratio of 20 g L−1, (iii) ChCl:BSA:Ethanol with a molar ratio of 1:1:2 and (iv) a reaction time of 2 h. The kinetics of the leaching process shows that the leaching is controlled by a surface chemical reaction. Furthermore, the Co2+ in the leachate can be directly converted into Co3O4 via precipitation of H2C2O4 and NaOH and calcination. The recovered high-value product Co3O4 can regenerate the LiCoO2 cathode material. This study provides a new method for the green recovery of spent LIB cathode materials with high efficiency and low energy consumption.

A gel polymer electrolyte based on ternary deep eutectic solvent for flexible, wide-temperature tolerant zinc-ion hybrid supercapacitors

Aqueous zinc ion hybrid supercapacitor (ZIHS) is attracting considerable interest due to its noticeable safety, low cost, and high theoretical energy density. However, the widely used hydrogel electrolytes suffer from freeze and evaporation issues, which hinder the practical applications of ZIHS over a wide temperature range. Herein, we develop a gel polymer electrolyte (GPE) based on a ternary deep eutectic solvent (DES) with a low eutectic point (<-90 °C). The optimal GPE not only shows excellent flexibility and satisfactory mechanical properties in the temperature from −40 °C to room temperature, but also exhibits high ionic conductivity of 7.3 mS cm−1 at −40 °C. When it is served as the electrolyte in a ZIHS, it endows the ZIHS with an energy density of 66.83 Wh kg−1 at a power density of 187.96 W kg−1 and outstanding cycling stability with ∼95.5% capacitance retention after 20000 cycles. Furthermore, the assembled flexible device indicates favorable bendability and outstanding wide-temperature adaptability from −40 to 60 °C. More importantly, the flexible device still works well under various harsh conditions, such as pressing, bending, puncturing, and cutting. The obtained results can provide new guidance and insight for exploring wide-temperature tolerant GPEs for ZIHS.

The Effect of Acidic Ternary Deep Eutectic Solvent Treatment on Native Lignin

Ternary deep eutectic solvents (DESs) are gaining increased attention to serve as a cheap green alternative medium for the processing of lignocellulosic biomass. For example, mixtures of choline chloride (ChCl), ethylene glycol (EG), and oxalic acid (OA) were recently explored for the fractionation of lignocellulosic biomass into its main components. Interestingly, during this processing, the recovered lignin was structurally modified by incorporation of EG, which altered its solubility properties and led to the need for different lignin recovery strategies. This offers an excellent starting point for a deeper investigation of the effect of acidic DES systems on the structure of lignin. In particular, native-like residual enzyme lignins (RELs) that are hard to completely dissolve in organic solvents are specifically suitable for this task. Here, a ternary DES is used consisting of ChCl/EG with OA or trifluoromethanesulfonic acid (HOTf) as a third component. The results showed that both solvent systems led to high EG incorporation into REL. The HOTf system showed a lesser extent of lignin depolymerization at similar modification levels as it already induced modification at lower temperature (25–30 °C). Low recovery yields from typical acidic precipitation were observed for treatment with both acidic DES systems. Analysis of THF and DCM extracts showed that the products in the water phase included small EG modified lignin fragments and aromatic monomers released from lignin aryl ether linkage cleavage. This analysis details the types of other products that can be expected and where these will end up during fractionation. These results show that the treatment of lignin with acidic DES in the presence of alcohols leads to low- and high-molecular-weight products that are not effectively recovered by typical precipitation procedures.

Low-condensed lignin and high-purity cellulose production from poplar by synergistic deep eutectic solvent-hydrogenolysis pretreatment

This paper presented a green and environmentally friendly method to obtain lignin with a structure similar to milled wood lignin (MWL) and high-purity cellulose from biomass in a two-step process. The first step, maleic acid (MA), choline chloride (ChCl), and ethylene glycol (EG) ternary deep eutectic solvent (DES) pretreatment was performed to obtain lignin with less-condensed structure. The results showed that the obtained lignin had similar properties to MWL under the condition (MA/ChCl/EG = 1:5:15, 80°C, 10 h). The DES recovered still had good cycle performance. The second step, the cellulose-rich residue was hydrogenated with isopropanol-water solvent and Raney nickel to obtain high-purity cellulose. The results showed that the purity of cellulose obtained by catalytic hydrogenolysis was > 94%. The glucose yield after enzymatic hydrolysis was 243.72 mg/g, which was 14.7 times higher than the untreated poplar. Overall, this work was of great significance for the effective separation of biomass.

Constructing ternary deep eutectic solvents with multiple sites for ammonia storage

Ammonia is a key chemical raw material and a promising carrier for the store and transportation of renewable energies. The absorption or adsorption of ammonia is an important part for the current air pollution control and the forthcoming green ammonia synthesis. Deep eutectic solvent (DES) has the advantages of excellent designability and environmental friendliness, and has thus been actively investigated in gas absorption. Herein, we report a type of ternary DESs with multiple active sites for binding NH3, that are consisting of 4-Amino-4H-1,2,4-triazole (Atri), glycerol (Gly), and resorcinol (Res). The effects of DES composition, temperature, and NH3 partial pressure on the NH3 absorption performance were systematically investigated. A high ammonia capacity of 0.193 g NH3 per g DES is achieved over the ternary DES Atri/Res/Gly (1:5:4) at 313.15 K and 0.1 MPa, which is superior to most previously reported DESs. NMR and FT-IR spectroscopy characterizations suggest that the formation mechanism of DESs and the absorption mechanism of NH3 are based on the formation of hydrogen bonds, and the multiple absorption sites of DESs enable them to obtain high NH3 absorption capacities.

Magnetic Fe3O4 nanoparticles in melamine-based ternary deep eutectic solvent as a novel eco-compatible system for green synthesis of pyrido[2,3-d]pyrimidine derivatives

Deep eutectic solvents (DESs) are among novel and more eco-friendly alternatives to ionic liquids (ILs) prepared by combining the components and the hydrogen bonds developed between them. The strong hydrogen bond interactions between the constituents of DESs make a considerable decline in the melting points in comparison to pure constituents. These green solvents have unique properties, making them a reliable and safe alternative to ILs and conventional organic solvents. In this study, we investigate the role of Fe3O4 nanoparticles (NPs) in Lactic acid:Melamine:NH4Cl (as a novel deep eutectic solvent) in the green synthesis of pyrido[2,3-d] pyrimidine derivatives. The prepared DES was characterized using FT-IR, 1H NMR, 13C NMR, TGA/DTA, DSC and physical properties, including viscosity, acidity, refractive index, surface tension, and density. The DES used during the experiments plays both catalytic roles and serves as a green environment for this reaction. In addition, magnetic DES can operate under very mild reaction conditions and be recycled easily with no significant catalytic activity loss. The fast and complete synthesis and high yield of the desired product are the remarkable benefits of this catalytic system.