Chloride-ethylene Glycol Deep Eutectic Solvent Research Articles

Molecular-Scale Interactions in the Choline Chloride-Ethylene Glycol Deep Eutectic Solvent System: The Importance of Chromophore Charge in Mediating Rotational Dynamics.

We report on the rotational diffusion dynamics of three chromophores (disodium fluorescein, oxazine 725, and perylene) in a series of choline chloride-ethylene glycol (ChCl:EG) deep eutectic solvent (DES) systems. We observe behavior independent of DES bulk viscosity for the cationic and neutral probes and behavior that is consistent with stick-limit interactions for the modified Debye-Stokes-Einstein model for the anionic probe. This finding indicates that the anionic species is integral to the interactions between DES constituent species that are responsible for local organization, consistent with previous MD simulations that showed higher interaction energies associated with both the hydrogen bond donor (EG) and hydrogen bond acceptor (Ch+) interactions with Cl- in ChCl:EG mixtures. The reorientation data reported here also indicate a region around 15 mol % ChCl where the stoichiometric relationship between the species gives rise to changes in the details of intermolecular interactions.

Recovery of highly pure copper from waste cupronickel by electrolysis separation with low energy consumption: The role of deep eutectic solvent

The recovery of waste cupronickel not only can solve related environmental concerns but also facilitates the separation of valuable metals and reduces extra exploitation of natural ore resources. Here, high-efficiency and low-energy-consumption separation of copper (Cu) from waste 90/10 cupronickel (Ni ∼ 10 %) by electrolysis was clarified in choline chloride-ethylene glycol deep eutectic solvent (ChCl-EG DES). Electrochemistry showed that Cu can be dissolved feasibly as monovalent Cu(I), forming species such as [CuCl2]− and [CuCl3]2−, while Ni was restrained and entered into anode slime at controlled potential. Compared with Ni(II), Cu(I) can be easily reduced to Cu0, and elevating temperature can accelerate ions transportation and reduction rates. Potentiostatic electrolysis at bath voltage of 0.4 V found that highly pure Cu (99.9918 wt%) was obtained and the current efficiency reached up to 99.71 % with low specific energy consumption (169.18 kW·h·t−1). A separation mechanism model of Cu from waste 90/10 cupronickel was proposed and the role of the DES was revealed, which possessed strong coordination ability and fast transport capacity for Cu(I), as well as significant potential difference between Cu and Ni. This strategy represents a promising and economical technique for recycling waste Cu-based alloy and extracting highly pure metals.

Synthesis and Characterization of a Modified Silica/Cellulose Acetate Nanocomposite Ultrafiltration Membrane for Phenol Removal from Wastewater

In addressing the critical environmental challenge of phenol pollution in water sources, this work studies phenol removal from wastewater using advanced ultrafiltration membranes. These membranes are enhanced with hydrophilic nanoparticles, specifically silica-based ones, to boost their efficiency and effectiveness. The process involves creating cellulose acetate (CA) mixed-matrix membranes, where silica nanoparticles are initially coated with a choline chloride-ethylene glycol deep eutectic solvent (DES). This composite is then incorporated into the CA membranes at varying concentrations of 0.25 %, 0.5 %, and 0.75 % by weight using phase inversion. The membranes are thoroughly examined for their structure and performance utilizing scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, contact angle measurements, pore size analysis, porosity assessment, and mechanical strength tests.Additionally, water flux and phenol removal performance tests were performed using a dead-end filtration setup at a pressure of 1 bar. Incorporating DES-modified nanofillers significantly enhances the membranes’ hydrophilicity and phenol removal efficiency. The internal structure exhibits a finger-like morphology with increased porosity and larger pore sizes. Notably, the membrane fabricated with 0.5 wt% modified nanoparticles showed the highest phenol removal (about 74 %) for 30 ppm aqueous phenol and water flux of 126.38 L m−2h−1. This indicates that using modified nanoparticles (DES-SiO2) in engineering ultrafiltration (UF) membranes results in an enhanced pore structure, improved chemical properties, and the effective removal of small molecules, including phenol.

A novel carbon coating by electrochemical deposition in deep eutectic solvent with the assistance of ammonium chloride for stainless steel bipolar plates

In this work, pulse electrodeposition method was proposed to directly deposit amorphous carbon coating (ACC) onto 316L stainless steel substrate in choline chloride-ethylene glycol deep eutectic solvent (DES) mixed with ammonium chloride (NH4Cl) to fabricate bipolar plates. The obtained dense ACC has a thickness of ∼400 nm. Potentiodynamic and potentiostatic polarization tests demonstrated that the corrosion current density of ACC coated 316L steel was of the order of 10−7 A cm−2 in the simulated proton exchange membrane fuel cells (PEMFC) working environment, and the self-corrosion potential of the coating positively shifted by 0.4V, indicating a significant improvement on corrosion resistance of the coated steel plate due to excellent electrochemical stability of ACC. The Rockwell C indentation test showed that the as-obtained ACC was strongly bonded to the substrate and also had high in-plane strength. Further numerical simulation and comparison experiments showed that C was chemically bonded with Fe in the substrate, which was boosted by the assistance of NH4Cl. The intact and strong bonding between ACC and the substrate is highly helpful to improve corrosion resistance. The success in coating stainless steel plate with ACC by pulse electrodeposition method provides a promising alternation for coating of proton exchange membrane electrolyzer cell (PEMEC) and PEMFC metal bipolar plates.

Electrochemical sensor based on hollow Au/Pd/Ag dendrites prepared by galvanic replacement from a choline chloride-ethylene glycol deep eutectic solvent

This study presents a simple approach to fabricating a hollow dendritic Au/Pd/Ag electrode through a galvanic replacement reaction (GRR) in a choline chloride-ethylene glycol deep eutectic solvent. The resulting electrode's morphological, structural, and compositional features were characterized using SEM, TEM, XRD, and XPS techniques, with the XPS depth profile providing insights into metal content ratio variations along the electrode's depth. The results emphasize the significant impact of immersion time on both morphological evolution and composition. Cyclic voltammetry investigations revealed significantly enhanced current density in furaltadone (FTD) detection compared to bimetallic and single metallic electrodes. The proposed electrochemical sensor exhibited a dynamic linear range for FTD spanning 1.67–625 μM, accompanied by a low detection limit of 91.7 nM, as confirmed by differential pulse voltammetry (DPV) quantitative experiments. The selectivity, reproducibility, stability, and recovery of the as-prepared sensors were evaluated, particularly in aquaculture water samples, underscoring the practical applicability of the electrodes for furaltadone sensing. This innovative trimetallic electrode design opens avenues for advanced electrochemical sensors with enhanced performance characteristics.

ZnxCo(1−x) coatings from choline chloride-ethylene glycol deep eutectic solvent as electrocatalysts for hydrogen evolution reaction

Hydrogen has emerged as a clean and renewable energy and its production by water splitting is a promising production route. However, to meet the demand on a commercial scale, research focusing on more efficient electrocatalysts is necessary. In this work, new findings on Zn, Co and Zn-Co coatings produced in deep eutectic solvent based on choline chloride (ChCl) and ethylene glycol (EG) are reported. Varying the concentrations of Zn2+ and Co2+ ions in 1ChCl:2EG, crystalline electrodeposits with fine control of composition and morphology were obtained, and which present different reactivity to electrocatalyze the hydrogen evolution reaction (HER) in alkaline medium. The performance of metallic coatings is influenced by temperature, due to changes in viscosity, ionic diffusion coefficient and charge transport in the electrolyte. The results also revealed that increasing the Co content in the coatings, changes occur in the morphological organization, stability, and electrode area, which positively influence the hydrogen production. Among the different coatings tested (Zn, Co, Zn96-Co4 and Zn3-Co97), Zn3-Co97 was the most promising in terms of Tafel coefficient (108 mV dec–1), exchange current density (8.57 × 10−6 A cm−2) and overpotential estimated for HER (333 mV at 10 mA cm−2) in 1 mol L–1 KOH at 298.15 K, although the other materials also showed electrochemical advantages over the unmodified Cu substrate. The reported data also reiterate the great electrochemical potential of metallic coatings for water splitting and complement the growing energy demand for hydrogen gas.

Aggregation behavior of sodium dioctyl sulfosuccinate in water-contained choline chloride-ethylene glycol deep eutectic solvent and its effects on electrochemical behavior of copper ions

Aggregation behavior of sodium dioctyl sulfosuccinate in water-contained choline chloride-ethylene glycol deep eutectic solvent and its effects on electrochemical behavior of copper ions

Understanding the electrochemical behavior of Sn(II) in choline chloride-ethylene glycol deep eutectic solvent for tin powders preparation

• Tin could be efficiently electrodeposited from ChCl-EG DES without any additives. • The nucleation mechanism and kinetics were assessed from j - t plots. • Homogeneous tin powders with dendritic structure could be obtained with the current efficiency of 96.4%. Tin is one of the vital substances in the material and chemical industry. Deep eutectic solvent (DES) possesses excellent physicochemical properties for metal preparation. In this study, the electrochemical behavior of Sn(II) and metallic tin preparation in choline chloride-ethylene glycol (ChCl-EG) DES were investigated. Linear sweep voltammetry is carried out to study the effects of substrate material (Ni, Cu, Pt, C, Fe, Al, W, glassy carbon (GC) and Ti), temperature (313–353 K) and SnCl 2 concentration (10–100 mM) on the electrochemical behavior of Sn(II)/Sn. Results demonstrate that metallic tin is easier to be prepared on the Ni electrode, and increasing temperature and SnCl 2 concentration both facilitate the reduction of Sn(II). Electrospray ionization mass spectrometry (ESI-MS) shows that the main form of Sn(II) is [SnCl 3 ] - . Chronoamperometric tests indicate that with the increase of applied potential, the nucleation of Sn(II) on the nickel electrode becomes close to the instantaneous nucleation. Simultaneously, the nucleation rate and the number of active sites on the electrode surface increase significantly. Pure tin with a dendritic structure could be prepared with higher current efficiency of 96.4% and lower energy consumption of 320.5 kW·h·t −1 without any additives. All these studies provide a fundamental basis for the preparation of tin powders in ChCl-EG DES.

Cobalt-phosphorous coatings with tunable composition fabricated by additive-controlled electrodeposition from choline chloride-ethylene glycol deep eutectic solvent for anti-corrosion application

Cobalt-phosphorous (CoP) coatings are promising alternatives for hard chromium due to their outstanding corrosion protection. An excellent CoP coating can efficiently reduce the effects of a corrosive environment. Herein, CoP coatings with a tunable P content, ranging from 5.1 at.% to 20 at.%, are fabricated via a simple electrochemical deposition approach from choline chloride-ethylene glycol (Ethaline)-based deep eutectic solvent (DES) with saccharin (SA) as an additive. The rational introduction of SA induced the formation of close-growing CoP coatings rich in P on the substrate with reduced grain size and surface roughness. It turned out that the crystal structure of the deposited CoP coatings changed from a crystallized state to an amorphous state upon the addition of SA, which accelerated the nucleation rate of the nanocrystals and modified the nucleation model from progressive to instantaneous. The optimal CoP coating prepared exhibited excellent anti-corrosion and barrier protection properties for mild steel in corrosive NaCl solution, functioning up to 10 times better than its counterparts. Our work reveals the central role of additives in tailoring the structure and composition of the deposited CoP coatings in Ethaline-based DES and offers a new avenue for fabricating high-performance coating materials for anti-corrosion applications.

One-step preparation, characterization and adsorption property of mesoporous nickel sulfides in deep eutectic solvent

In this paper, single and mixed-phase mesoporous nickel sulfides (including α-NiS/β-NiS/Ni3S4, Ni3S4, Ni3S4/NiS2 and NiS2) are prepared in choline chloride-ethylene glycol deep eutectic solvent (ChCl-EG DES) under normal atmosphere. In the preparation processes, the ChCl-EG DES plays dual roles as solvent and template. The effects of NiSO4·6H2O, Na2S2O3·5H2O and ethylenediamine tetraacetic acid concentrations on the phase, morphology, element composition and specific surface area of the products are examined. The results show that pompon-like, cauliflower-like, botryoid and nanospherical nickel sulfides can be obtained by controlling the concentration of the reactants. Their specific surface areas are 4.063 m2/g, 5.138 m2/g, 4.533 m2/g and 52.135 m2/g, respectively. The reaction mechanism for the preparation of nickel sulfides in ChCl-EG DES is also elaborated. In addition, the adsorption property and mechanism of nickel sulfides are assessed with methylene blue (MB) as target organic pollutant. The adsorption process on MB follows the pseudo-second-order kinetics and Langmuir isotherm models. Their maximum adsorption capacity for MB are 20.39 mg g−1, 19.56 mg g−1, 21.38 mg g−1 and 24.38 mg g−1, respectively.

Electrochemical Separation of High-Purity Sb from Pb-Containing Sb Alloy in Choline Chloride-Ethylene Glycol Deep Eutectic Solvent

Electrochemical Separation of High-Purity Sb from Pb-Containing Sb Alloy in Choline Chloride-Ethylene Glycol Deep Eutectic Solvent

Influence of Pre-Adsorbed TiO2 Particles on the Nucleation and Growth Mechanism of Ni in Deep Eutectic Solvent Electro-Codeposition

Electrodeposition holds excellent potential for creating controllable nanoscale functional interfaces. However, the key characteristics of these processes remain elusive, especially the composite electrodeposition processes involving inert nanoparticles. Herein, the pre-adsorption of inert particles is considered in detail in electro-codeposition. The nucleation and growth mechanism of nickel nanoparticles under the influence of pre-adsorbed inert particles is studied in a choline chloride–ethylene glycol deep eutectic solvent (DES). Cyclic voltammetry results show that pre-adsorbed TiO2 particles can significantly increase the cathodic reduction current, while codeposited TiO2 particles hinder the reduction process. Chronoamperometry analysis demonstrates that pure Ni electrodeposition in a DES follows the mechanism of instantaneous nucleation and tridimensional growth at a high potential, while the Ni electrodeposition deviated from the instantaneous nucleation model due to the pre-adsorption of TiO2 particles. Moreover, considering the classical model description of multiphase 3D nucleation and diffusion-controlled growth, the typical kinetic parameters such as nucleation rate constant and diffusion coefficient were investigated under different applied potentials. It was found that the nucleation rate constant of Ni electrodeposition increased significantly in the presence of pre-adsorbed TiO2 particles. These findings are of great significance for understanding and perfecting the electro-codeposition process containing inert nanoparticles.

Electrochemical Fabrication of Tin Films on Different Substrates in a Choline Chloride–Ethylene Glycol Deep Eutectic Solvent Containing Boric Acid

Electrochemical Fabrication of Tin Films on Different Substrates in a Choline Chloride–Ethylene Glycol Deep Eutectic Solvent Containing Boric Acid

Spectroscopic Study into Lanthanide Speciation in Deep Eutectic Solvents.

Deep eutectic solvents are a new class of green solvents that are being explored as an alternative for used nuclear fuel and critical material recycling. However, there is a paucity of knowledge regarding metal behavior in them. This paper explores the underlying chemistry of rare-earth elements in choline chloride-based deep eutectic solvents by using a multi-technique spectroscopic methodology. Results show that speciation is highly dependent on the choice of the hydrogen-bond donor. Collected EXAFS data showed Ln3+ coordination with ethylene glycol and urea in their respective solvents and coordination with chloride in the lactic acid system. Generalized coordination environments were determined to be [LnL4–5], [LnL7–10], and [LnL5–6] in the ethylene glycol, urea, and lactic acid systems, respectively. Collected UV/vis spectra for Nd3+ and Er3+ showed variations with changing solvents, showing that Ln–Cl interactions do not dominate in these systems. Luminescence studies were consistent, showing varying emission spectra with varying solvent systems. The shortest luminescent lifetimes were observed in the choline chloride–ethylene glycol deep eutectic solvent, suggesting coordination through O–H groups. Combining all collected data allowed Eu3+ coordination geometries to be assigned.

Eco-Friendly Extraction of Lead from Galena by In Situ Electrochemical Reduction in ChCl-EG Deep Eutectic Solvent

One-step electrochemical extraction of metallic lead from solid galena in choline chloride-ethylene glycol deep eutectic solvent (ChCl-EG DES) was studied for the first time. Cyclic voltammetry on a Pt powder microcavity electrode shows that solid galena can be directly reduced to metallic lead by a one-step, two-electron transfer reaction at a potential of −0.47 V (vs Ag). The constant voltage electrolysis using galena powders as cathode in the range of 5 h to 30 h reaction time and 3.0 V to 3.8 V cell voltage further proves that metallic lead can be obtained at the cathode. With the extension of reaction time, the morphology of lead powders transforms from interconnected wax to irregular rod-like and needle particles. As the cell voltage is elevated, the microstructure of metallic lead changes from irregular flake and rod to nano-needle particles. The direct electrolysis process of solid galena is analyzed, and a schematic diagram is also exhibited. It is pointed out that the close contact between galena powders and current collector is the key to facilitate the in situ reduction. These findings put forward a green and convenient route for direct extraction of metals from sulphide ores at near room temperature.

High-efficiency separation of Ni from Cu-Ni alloy by electrorefining in choline chloride-ethylene glycol deep eutectic solvent

High-purity Cu powders (99.967%) can be obtained by the electrorefining of Cu-Ni alloy (Ni ≤ 5%) in choline chloride-ethylene glycol deep eutectic solvent (ChCl-EG DES) at near room temperature. The electrochemical separation behaviors of Cu and Ni have been investigated by linear sweep voltammetry in 0.1 M CuCl + ChCl-EG DES. The results show that the oxidation potential of Cu is more positive than that of Ni, which implies Cu and Ni can be separated by electrochemistry. And the increasing of temperature is beneficial to the decontamination of Ni from Cu-Ni alloy. Besides, the effects of current density (2–10 mA·cm−2) and reaction temperature (323–363 K) on the current efficiency and specific energy consumption during the electrorefining process are also analyzed, respectively. The highest current efficiency (99.89%) and the corresponding specific energy consumption (281.492 kW·h·t−1) can be achieved at 10 mA·cm−2 and 363 K. The morphologies of Cu powders change from cauliflower-like to wheat ear-like with the increasing of current density. This finding provides a theoretical guidance for the separation of Ni from Cu-Ni alloy by an eco-friendly and facile electrorefining in ChCl-EG DES.

Electrochemical behavior of Sb(III)/Sb during the preparation of Sb particles in deep eutectic solvent

The electrochemical behavior of Sb(III)/Sb has been preliminarily clarified during the preparation of antimony (Sb) particles in choline chloride-ethylene glycol deep eutectic solvent (ChCl-EG DES) at 333 K. Cyclic voltammetry reveals that the reduction of Sb(III) to Sb on Ti electrode is a quasi-reversible process and the diffusion coefficient DSb(III) remains in the range of 1.822×10−7 to 5.938×10−7 cm2·s−1 at 333 K. The effect of SbCl3 concentration (10–100 mM) on the cathodic and anodic polarization processes is discussed by linear sweep voltammetry. Meanwhile, the chronoamperometry analysis demonstrates that the initial nucleation of Sb on Ti electrode is fit well with the three-dimensional progressive nucleation model at 10 mM SbCl3, and then transformed into a non-three-dimensional nucleation process at 50–100 mM. Additionally, cauliflower-shaped Sb particles in size of 1–1.2 μm can be deposited onto a Ti substrate at different applied potentials (−0.525 V to −0.675 V) and reaction times (10–600 s), which are formed by the aggregation of multiple spherical grains. Increasing the concentration of Sb(III) induces the formation of snowflake-shaped Sb particles.

Enhanced removal of aqueous phenol with polyimide ultrafiltration membranes embedded with deep eutectic solvent-coated nanosilica

Novel composite hydrophilic ultrafiltration (UF) membranes, comprising a polyimide (PI) matrix embedded with silica-based nanofillers are established for the enhanced vacuum-filtration removal of small polar organics such as phenol from water. Spherical silica nanoparticles are first prepared by the surfactant-templated sol–gel approach, then coated with choline chloride-ethylene glycol deep eutectic solvent (DES) by post-impregnation. Themodified silica nanofillers are introduced into the PI matrix through the casting solution, which is then used to develop the composite UF membranes by phase inversion. Thespectroscopy and high-resolution electron microscopy measurements evidence thepresence of DES on the surface of the modified silica nanofillers. Thetopographical atomic force microscopy studies, dynamic water contact angle, and zeta potential measurements conducted on the native polymer membrane and those embedded with bare-silica and DES-coated silica confirm the successful incorporation of nanofillers into the PI matrix. Anoptimum nanofiller loading of 2 wt% is found to preserve the membrane structure and give the best mechanical properties as well as for the UF performance characteristics in vacuum-filtration studies at 85 kPa. Consistently, the DES-silica modified PI UF membranes (DES@SiO2@PI) exhibit exceptional water permeate flux (300 L m−2 h−1) and removal efficiency (96%) for 30 mg L−1 aqueous phenol compared with the native polymer and SiO2-modified membranes. The DES-engineered composite membranes can be operated within a wide feed pH window (pH: 2–10) without displaying significant loss in their removal efficiency. The pH and zeta potential results suggest that the interaction of phenol with the optimized membranes is governed by cooperative adsorption/Lewis acid-base mechanisms via hydrogen bonding and assistive ion-exchange interactions with the ethaline coating.

Facile and controllable synthesis of NiS2 nanospheres in deep eutectic solvent

A facile and controllable approach was used to synthesize NiS2 nanospheres for the first time, and the process was carried out in choline chloride-ethylene glycol deep eutectic solvent (ChCl-EG DES) under normal atmosphere. The effects of reaction temperature on the phase and microstructure of the products were investigated. It is found that the high-purity and well-crystallized NiS2 was synthesized at 110 °C for 3 h and confirmed by the XPS test. The uneven surface and some small bumps were observed on the nanoparticle. In the synthesis process, DES acts as a solvent, providing a mild reaction environment for the synthesis that significantly reduces the requirements for experimental equipment and conditions.

Preparation of Ni nanotube-modified electrodes via galvanic displacement on sacrificial Zn templates: Solvent effects and attempts for non-enzymatic electrochemical detection of urea

In this study, Ni nanotube-modified stainless-steel electrode (SSE\\Nianodized) was prepared by galvanic displacement on tangled Zn nanowire-composed sacrificial template (SSE\\Zn) followed by anodization in 1 M NaOH. The tangled Zn nanowires were electrodeposited from an amide-type room temperature ionic liquid (RTIL) 1-butyl-1-methypyrrolidinium bis((trifluoromethyl)sulfonyl)amide ([BMP][TFSA]) containing ZnCl2, and then galvanic displacement was conducted in the same RTIL with [NiCl4]2−. The process was unable to be reproduced by using water or choline chloride-ethylene glycol deep eutectic solvent (ChCl-EG DES) as the reaction media, indicating the unique properties of RTILs. The cations of RTILs are critical to successfully retaining the skeleton of Zn-nanowire-template. SSE\\Nianodized showed high activity towards the oxidation of urea and possessed a detection limit of 3 μM, a sensitivity of 902.8 μA·mM−1·cm−2, and a dynamic range of 1–20000 μM. Most importantly, the electrode could be regenerated by anodization in 1 M NaOH to remove adsorbed urea without significantly altering the surface morphology and performance of the electrode. A low background current was achieved after the regeneration process, which is important for repeatedly using the same electrode in urea determination.