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.     

基于尿素/氯化胆碱低共熔溶剂体系纳米流体制备及其热物性研究

随着电子工业的快速发展,传统换热工质由于其较低的热导率已无法满足越来越高的换热需求。另一方面,传统的换热工质受限其相对较窄的液程范围而无法使用于复杂的温况或特殊的工作条件。低共熔溶剂（DESs）具有与离子液体相似的低饱和蒸气压、高沸点及强稳定性等优势,在传热领域具有巨大的潜力。制备了以尿素/氯化胆碱低共熔溶剂体系为基液,石墨烯、Al₂O₃、TiO₂三种纳米粒子填充的纳米流体,研究了黏度、热导率等热物性与纳米粒子和基液组成之间的关系,并系统地研究了纳米粒子结构对其稳定性的影响。实验结果表明,纳米粒子的填充会在一定程度上增加基液的黏度,其中石墨烯填充的纳米流体的黏度增加最大。此外,石墨烯能显著提高DESs的导热性能,其中6%（质量）石墨烯纳米流体热导率相比基液可增加29.0%。     

Kinetics of polyvinyl butyral (PVB) synthesis reaction catalyzed by deep eutectic solvent

In this work, the kinetics of the polyvinyl butyral (PVB) synthesis reaction catalyzed by the deep eutectic solvents (DESs) at the low-temperature stage was studied to control the particle size of PVB resin and optimize its synthesis process. The effects of stirring speed, the concentration of polyvinyl alcohol (PVA), catalyst dosage, and temperature on the synthesis reaction of PVB were investigated. The data obtained from kinetic experiments at 283.15–298.15 K were fitted with the shrinking core models, and the results showed that the model controlled by internal diffusion fitted well with the experimental data. The internal diffusion coefficient, D_A, of n-butanal in the product layer was further calculated by the obtained model parameters, and it was applied to predict the synthesis reaction of PVB at different concentrations of n-butanal. The results indicated that the shrinking core model controlled by internal diffusion is suitable to describe the kinetics of the PVB synthesis reaction. DES played a dual role in catalysis and dispersion in the synthesis of PVB, and it was a green catalyst with good potential for PVB industrial applications.     

Differential capacity of a deep eutectic solvent based on choline chloride and glycerol on solid electrodes

The properties of the interface between platinum, gold and glassy carbon electrodes and a deep eutectic ionic liquid based on choline chloride and glycerol were assessed using cyclic voltammetry and electrochemical impedance spectroscopy. The double layer differential capacitance, obtained from electrochemical impedance, reveals a slight dependence of the potential but it is sensitive to the electrode material. In contrast to high temperature inorganic melts the differential capacitance increases with temperature.     

Lithium storage performance of FeS@graphene anode materials prepared in a deep eutectic solvent

FeS has received widespread attention due to advantages such as high capacity, low-budget, and friendly to the environment. But side reactions during the charging and discharging process result in volume expansion of FeS, which limits its application and further development. In this work, FeS@graphene composites were prepared by a single step pyrolytic sulfidation method using PEG as the carbon source, FeCl₃·6H₂O as the iron source, metal chloride and organic alcohol as a deep eutectic solvent. The prepared composites which were characterized by SEM and TEM exhibited a strong bond between FeS and graphene, graphene had a lamellar structure, and FeS nanoparticles formed a homogeneous dispersion. Among the prepared composite material electrodes, the FeS/G-550 electrode displayed the best electrochemical properties with a high specific capacitance (initial discharge capacity: 1200 mAhg^-1; current density: 0.1 A g^-1), excellent rate capability (discharge specific capacitance of 443 mAh·g^-1 at the current density of 5 A g^-1), and good cyclic stability (capacity retention rate: 91%).     

Use of deep eutectic solvent as extractant for separation of Fe (III) and Mn (II) from aqueous solution

In this work, we used deep eutectic solvent (DES) composed of decanoic acid and lidocaine, which is characterized as a green solvent, for separation of Fe (III), which is the most-used metal in the world, and Mn (II), which is currently being used in many industries. We found that the pH of the initial metal solution strongly influenced the extraction mechanism. Fe (III) can be extracted at pH 1.0–2.0 due to the ion pair reaction between Fe³⁺ and decanoic anion, while at higher pH, the extraction mechanism cannot be evaluated due to formation of precipitation at the aqueous phase. In the case of Mn (II), the ion pair reaction occurred at pH of lower than 2.2 and higher than 3.5, while from pH 2.2 to 3.5, the cation exchange between Mn²⁺ and lidocaine cation probably dominated the extraction process. The DES concentration needed to reach the complete separation of Fe (III) was about 25 g/L, while Mn (II) was completely extracted using about 300 g/L of DES. The selectivity of this method was very high when was applied in the separation of Fe (III) from Mn (II).     

Extraction of ferulic acid from oil palm pressed fiber by a choline chloride based deep eutectic solvent

Results on the extraction of ferulic acid from palm pressed fiber using deep eutectic solvent (DES) of choline chloride-acetic acid (ChCl-AA) and choline chloride-citric acid (ChCl-CA) are reported. Acetic acid was found to be a better hydrogen bond donor to choline chloride than citric acid for the extraction of ferulic acid. Influence of water content in both DES was investigated whereby ChCl-AA and ChCl-CA experienced a drop in viscosity from 9.678 to 1.429 and 22.658 ± 1.655 mm²/s, respectively as the water content in the DES increased from 0 to 50 wt%. The drop in viscosity contributed to higher extraction efficiency in which 41,155 ± 940 mg/kg ferulic acid was obtained after 6 h reflux when ChCl-AA with 30 wt% water was used for the extraction compared to 30,940 ± 621 mg/kg when neat ChCl-AA was used. Further increase in water content in the DES however, did not lead to higher extraction efficiency. Although viscosity of the DES could be improved with the addition of water, there is a threshold where the DES could tolerate the presence of water without changing its solvent behavior. Surface response model revealed that interaction between heating duration and water content in DES, as well as second order effect of both heating duration and water content in DES played important roles in the extraction of ferulic acid from oil palm pressed fiber. The optimum condition for extraction of ferulic acid from palm pressed fiber was heating for 6 h with DES containing 30 wt% water.     

Effects of SnCl2 concentration and Ti source on the phase composition,sinterability, and microwave dielectric properties of Zr0.8Sn0.2TiO4 ceramics by choline chloride-malonic acid deep eutectic solvent

Zr_0.8Sn_0.2TiO₄ (ZST) ceramics were prepared by choline chloride-malonic acid deep eutectic solvent (Cm-DES) route using analytical-grade raw materials such as Zr(CH₃COO)₄, SnCl₂·2H₂O, titanium isopropoxide, and so on. The effects of SnCl₂ concentration and Ti source on phase composition, sinterability, and microwave dielectric properties of ZST ceramics processed by Cm-DES routes were investigated. Single-phase ZST powders were processed by Cm-DES routes calcined at 450 °C, and no second phase was detected in all the ceramics. The sintering temperature of ZST ceramics processed by Cm-DES routes was seriously decreased to 1350 °C. Excellent dielectric properties (ε_r = 38.0, Q×f = 44,500 GHz, and τ_f = 1.9 ppm/°C) were obtained when 0.6 mol/L SnCl₂ and titanium isopropanol were employed. These results give the underlying enlightenments needed for cost-saving and low energy consumption fabrication of microwave dielectric ceramics.     

Microwave heating synthesis of spindle-like LiMnPO4/C in a deep eutectic solvent

Orthorhombic structure LiMnPO₄/C with space group Pnmb was synthesized using a microwave heating process in a chloride/ethylene glycol-based deep eutectic solvent (DES) at 130 °C for 30 min under atmospheric pressure. The prepared sample was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy and electrochemical tests. LiMnPO₄/C prepared in a DES has a nano-spindle form coated with a carbon layer (approximately 3 nm thick). This spindle-like LiMnPO₄/C material delivers a discharge capacity of 129 mA h g^–1 with a capacity retention ratio of approximately 96.1% after 100 cycles at 1 C. Even at 5 C, it still gives a discharge capacity of 106 mA h g^–1, exhibiting good rate performance and cycle stability. The results of this work show that the chloride/ethylene glycol-based DES can act as a crystal-face inhibitor to adjust the oriented growth and morphology of LiMnPO₄. Furthermore, deep eutectic solvents could find a wide application in the synthesis of electrode materials with special morphologies for lithium ion batteries.     

Development of dispersive liquid-liquid microextraction based on deep eutectic solvent using as complexing agent and extraction solvent: application for extraction of heavy metals

ABSTRACT

A green and efficient dispersive liquid-liquid microextraction method based on a new deep eutectic solvent has been developed for the preconcentration and extraction of cobalt and nickel ions. The deep eutectic solvent is formed by mixing choline chloride (hydrogen bond acceptor) and 4-aminophenol (hydrogen bond donor). Then, it is used as a chelating agent as well as extraction solvent. Under the optimum experimental conditions, the linear ranges for Ni(II) and Co(II) were 0.80–50 and 0.50–50 µgL^?1, respectively, by flame atomic absorption spectrometry. The obtained detection limits were 0.30 and 0.22 µg L^?1 for Ni(II) and Co(II), respectively.     

甲酸/盐酸胍DES温和高效分离毛竹木质素

以毛竹为原料,采用甲酸/盐酸胍酸性低共熔溶剂（DES）温和高效分离木质素,并对其结构、热稳定性和抗氧化性进行了表征。结果表明,甲酸/盐酸胍（摩尔比为4:1）DES实现了温和短时条件下（100 ℃,2 h）高效分离木质素（得率为59.31%）,当进一步升温至120 ℃时,得率可达73.98%,其原因是该酸性体系中氢质子使木质素中大量的β-O-4、β-β、β-5连接键断裂,促使木质素大分子解聚成小分子而溶出。分离的木质素纯度高于96.6%,分子量低（Mw=1040~2040 g/mol）,多分散系数小于1.5,结构均一,热稳定性好。同时,该木质素抗氧化活性强（IC50=0.016~0.045 mg/ml）,优于商业抗氧化剂丁基羟基茴香醚（IC50=0.056 mg/ml）。     

新型银基低共熔溶剂制备及其在1-己烯/正己烷分离中的应用

相同碳数的正构烯烃与正构烷烃因其结构相似,使其相对挥发度较小、分离难度较大。低共熔溶剂（DES）作为一种可设计的绿色分离介质被广泛应用于该类混合物的分离中,此外过渡金属与烯烃双键之间的化学络合作用是促进正构烯烃/烷烃分离的一个重要方法。鉴于此,开发了新型银基低共熔溶剂（Ag-DES）,并将其应用于1-己烯/正己烷的分离,系统探究了原料中烯烃浓度、银离子与烯烃摩尔比、分离温度等对1-己烯分离性能的影响,结果显示Ag-DES具有良好的1-己烯/正己烷分离选择性,选择性在3.5~18之间,并具有出色的循环稳定性。进一步通过FT-Raman表征和量化计算揭示了Ag-DES与烯烃之间的化学络合作用和较强氢键作用是实现其与烷烃分离的本质原因,表明应用Ag-DES的反应萃取分离强化方法可实现从F-T合成油中绿色高效分离C₆α-烯烃。     

锑离子添加剂对低共熔溶剂(DES)电解液液流电池的性能改善研究

非水系氧化还原液流电池（NARFB）的广泛应用受制于其较低的性能。在电解液中加入一些金属离子添加剂是一种可能的解决方案。实验研究了Sb³⁺离子对低共熔溶剂（DES）电解液液流电池电化学性能的影响。结果表明,添加Sb³⁺离子可以强化V（Ⅲ）/V（Ⅱ）氧化还原离子对的电化学反应动力学（最高可达22.6％）过程,钒离子在DES中的扩散系数提高了63.3％,并且电荷转移电阻降低了11.9％。场发射扫描电子显微镜表明,Sb³⁺离子电沉积在石墨毡的表面,对电化学反应起催化作用,从而改善了电化学性能。考虑增强的动力学和降低的活性比表面积之间的平衡,确定了Sb³⁺的最佳浓度为15 mmol·L^-1。此外,当使用含有Sb³⁺的负极电解液液流电池时,液流电池的功率密度提高了31.2%,从含原始电解质的3.08 mW·cm^-2到含15 mmol·L^-1 Sb³⁺离子的4.04 mW·cm^-2。这些结果为改善NARFB的电池性能提供了一个便捷而有前景的方法。     

Original synthesis of polyvinyl butyral with a green deep eutectic solvent and a weakly polyacrylic acid from polyvinyl alcohol and the impacts of the chains structures of polyvinyl alcohol

In this work, an environmentally-friendly deep eutectic solvent (DES) was employed as a catalyst to generate polyvinyl butyral (PVB) resins from polyvinyl alcohol (PVA) with a weakly acidic polymer (polyacrylic acid [PAA]) as an emulsifier. Finally, high viscosity PVB resins with molecular weight of 110,000–200,000 g · mol⁻¹ and acetalization degree above 83% were successfully synthesized, which was found to satisfy the requirements for interlayer films between safety glass. Furthermore, it was well proved that the properties of PVB resins immensely depend on the molecular structures of the PVA. The molecular weight of the PVB, independent of alcoholic degrees of the PVA, indicated an upward trend with the increase of the molecular weight of the PVA. As for these four PVBs with high molecular weight, the T_g was sensitive to the content of hydroxyl and acetal groups rather than molecular weight, associated with the inter- or intra-molecule hydrogen bond between  OH. PVB-1799 and PVB-1797 had higher T_i and T_g than that of PVB-1788 and PVB-1795 because the former had low contents of vinyl acetate group (VAc) and alcohol hydroxyl group (VOH). The tensile strength of PVBs was all higher than 30 Mpa, and the elongation at break was about 300% due to their high molecular weights.     

低共熔溶剂与偶联剂协同改性白炭黑对胎面胶性能的影响

研究了硅烷偶联剂(TESPT)与低共熔溶剂(DES)协同改性白炭黑对作为胎面胶的天然橡胶复合材料性能的影响.用傅里叶变换红外光谱分析了 TESPT和DES与白炭黑之间的相互作用,用橡胶加工分析仪和扫描电镜分析了白炭黑之间的相互作用,并测试了复合材料的硫化特性、力学性能和耐磨性,通过动态力学分析仪考察了其滚动阻力和抗湿滑...     

Sono-electrodeposition (20 and 850 kHz) of copper in aqueous and deep eutectic solvents

This paper reports the effects of ultrasound at different frequencies and powers upon the electrodeposition of copper(II) chloride in aqueous potassium chloride and in glyceline 200 (a deep eutectic solvent - DES) on Pt electrodes in the potential range for copper deposition and dissolution. It is shown that the deposition of copper in both solvents is greatly affected by ultrasound at the two frequencies of 20 and 850 kHz employed. Limiting current densities were obtained in both solvents under sonication at 20 and 850 kHz and a 10-fold and 5-fold increase in currents in aqueous potassium chloride and glyceline 200 compared to silent conditions was observed respectively. The difference in viscosity of water (KCl) and glyceline 200 was found to be a crucial parameter in the evaluation of limiting current densities.     

Investigation of CO2 solubility in monoethanolamine hydrochloride based deep eutectic solvents and physical properties measurements

Deep eutectic solvents (DESs) have drawn a growing research interest for applications in a wide range of scientific and industrial arenas. However, a limited effort has been reported in the area of gas separation processes and particularly the carbon dioxide capture. This study introduces a novel set of DESs that were prepared by complexing ethylenediamine (EDA), monoethanolamine (MEA), tetraethylenepentamine (TEPA), triethylenetetramine (TETA) and diethylenetriamine (DETA) as hydrogen bond donors to monoethanolamide hydrochloride (EAHC) salt as a hydrogen bond acceptor. The absorption capacity of CO₂ was evaluated by exploiting a method based on measuring the pressure drop during the absorption process. The solubility of different DESs was studied at a temperature of 313.15 K and initial pressure of 0.8 MPa. The DES systems 1EAHC:9DETA, 1EAHC:9TETA and 1EAHC:9TEPA achieved the highest CO₂ solubility of 0.6611, 0.6572 and 0.7017 mol CO₂·(mole DES)⁻¹ respectively. The results showed that CO₂ solubility in the DESs increased with increasing the molar ratio of hydrogen bond donor. In addition, the CO₂ solubility increased as the number of amine groups in the solvent increases, therefore, increasing the alkyl chain length in the DESs, resulted in increasing the CO₂ solubility. FTIR analysis confirms the DES synthesis since no new functional group was identified. The FTIR spectra also revealed the carbamate formation in DES-CO₂ mixtures. In addition, the densities and viscosities of the synthesized DESs were also measured. The CO₂ initial investigation of reported DESs shows that these can be potential alternative for conventional solvents in CO₂ capture processes.     

乳酸类低共熔溶剂分离油茶果壳木质素及其特性分析

以油茶果壳为原料,利用两种乳酸类低共熔溶剂（DES）[三乙基苄基氯化铵/乳酸（TEBAC/LA）和甜菜碱/乳酸（Bet/LA）]分离木质素,采用UV、FTIR、GPC、TG-FTIR对油茶果壳木质素元素组成、化学结构和抗氧化活性进行了表征和评价。结果表明,TEBAC/LA和Bet/LADES均表现出良好的木质素分离能力,在固液比（g∶m L）为1∶20,120℃反应5h,油茶果壳木质素提取率分别为77.87%和59.49%。油茶果壳木质素结构保留完整,主要由紫丁香基和愈创木酚基结构组成。与TEBAC/LA分离木质素相比,Bet/LA分离的木质素相对分子质量低、分散度低和结构均一。两种DES分离得到的木质素的失重速率、失重温度和热解产物均不同,说明不同木质素热稳定性存在差异。此外,两种木质素均表现出良好的抗氧化活性,其中Bet/LA分离的木质素对1,1-二苯基-2-苦基肼（DPPH）自由基清除率可达84.57%。