Ionic Liquid Modification Research Articles

Improvement of tetracycline removal using amino acid ionic liquid modified magnetic biochar based on theoretical design

In current research, biochar is widely used to remove antibiotic contamination from the environment. However, original biochar produced through direct pyrolysis has significant limitations in removing antibiotics. In this paper, response surface methodology provided the laudable choice for magnetic poplar biochar (MPBC) considering the synergistic effect of multi-factors as well as the restrictions abundance experiments during the preparation of MPBC. Amino acid ionic liquids (AAILs) are a class of ionic liquids in which amino acids act as the anionic component, combining the tunable properties of ionic liquids with the biocompatibility and functionality of amino acids. To ameliorate adsorption capacity of MPBC, tetra-ethylammonium glycinate ([TEA][Gly]) with the best affinity for tetracycline (TC) were screened from 600 AAILs based on theoretical predictions using the conductor-like screening model for real solvents (COSMO-RS) without extensive experimental. Furthermore, AAILs-modified magnetic biochar (MPBC-AAIL) was synthesized chemically for the first time. Adsorption kinetics, isotherms, and thermodynamic analyses revealed that TC adsorption by both MPBC and MPBC-AAIL is a monolayer, spontaneous, and exothermic chemical process. Moreover, MPBC-AAIL exhibited a maximum adsorption capacity of 305.9 mg·g−1. Meanwhile, MPBC-AAIL maintains superior adsorption performance for TC in different impurity solutions as well as in real water samples. The excellent reusability and selective adsorption capacity of the material demonstrate the superiority of the theoretical based design. The characterization reveals that the adsorption mechanisms include pore filling, π-π interactions, surface complexation, hydrogen bonding, and electrostatic interactions. In addition, theoretical calculations showed that ionic liquid modification altered the adsorption sites between TC and MPBC-AAIL, leading to enhanced adsorption. This comprehensive study introduces an innovative modification of biochar, providing a novel approach to designing biochar composites and promoting their application in the remediation of complex environmental pollution.

Enhancing DNA Translocation Performance and Conformational Changes in Quartz Nanopipettes by Ionic Liquid Modification

Enhancing DNA Translocation Performance and Conformational Changes in Quartz Nanopipettes by Ionic Liquid Modification

Modification of ionic liquid and lactoferrin-based small molecules as potential therapeutics against SARS-CoV-2: Molecular docking disclosed the predictable results

Ionic liquid MIE-NH2 displays a new role in the development of modification of glycoproteins of lactoferrin through a reductive amination mechanism to synthesize versatile pharmaceuticals. This work introduces a new strategy of modification of lactoferrin by using methyl imidazolium N-ethylamine MIE-NH2, this ionic liquid linked to N-glycans in lactoferrin derivatives in simple method. The modification of lactoferrin with MIE-NH2 as a novel small molecule (SM-IL-Lf) contains active amino groups is confirmed by UPLC/ESI-QTOF and MALDI-TOF mass spectrometry. Molecular docking disclosed the bioactivity of modifying glycoproteins - small IL-Lf-molecules by elucidating its interactions with the inspected targets. This providing of small molecules IL-Lf released a wide display with different functions as significantly important drug candidates inhibiting the targets of main protease (Mpro), RNA dependent RNA polymerase (RdRp), transmembrane protease serine 2 (TMPRSS2), and Papain-like protease (PLpro). The probability of the modeling N-glycans from lactoferrin modified and designed as small IL-Lf-molecules to inhibit any of these targets was investigated to find out its potency inhibitor of SARS-CoV-2.

Ionic liquid-functionalized covalent organic frameworks on the surface of silica for online solid-phase extraction

A covalent organic framework (COF) was gown on porous silica with 1,3,5-tri(4-aminophenyl)benzene and 2,5-divinyl-1,4-phenyldiformaldehyde as monomers, and two ionic liquids were grafted to COF by a click reaction. The materials before and after the modification of ionic liquids were separately packed into solid-phase extraction columns (10 × 4.6 mm, i.d.), which were coupled with liquid chromatography to construct online analysis systems. The extraction mechanisms of polycyclic aromatic hydrocarbons, bisphenols, diphenylalkanes and benzoic acids were investigated on these materials. There were π-π, hydrogen-bond and electrostatic interactions on ionic liquid-functionalized sorbents. After the comparison among these materials, the best sorbent was used, and the analytical method was established and successfully applied to the detection of some estrogens from actual samples. For the analytical method, the detection limit was as low as 0.005 μg L−1, linear range was as wide as 0.017–10.0 μg L−1, and enrichment ratio was as high as 3635. The recoveries in actual samples were 70 %-129 %.

Ionic Liquid Modification of High-Pt-Loading Pt/C Electrocatalysts for Proton Exchange Membrane Fuel Cell Application

Ionic Liquid Modification of High-Pt-Loading Pt/C Electrocatalysts for Proton Exchange Membrane Fuel Cell Application

Small Ionic‐Liquid‐Based Molecule Drives Strong Adhesives

AbstractNature has inspired scientists to fabricate adhesive materials for applications in many burgeoning areas. However, it is still a significant challenge to develop small‐molecule adhesives with high‐strength, low‐temperature and recyclable properties, although these merits are of great interest in various aspects. Herein, we report a series of strong adhesives based on low‐molecular‐weight molecular solids driven by the terminal modification of ionic liquids (ILs) and subsequent supramolecular self‐assembly. The emergence of high strength and liquid‐to‐solid transitions for these supramolecular aggregates relies on modifying IL with a high melting point motif and enriching the types of noncovalent interactions in the original ILs. Using this strategy, we demonstrate that our IL‐based molecular solids can efficiently obtain a high adhesion strength (up to 8.95 MPa). Importantly, we elucidate the mechanism underlying the reversible and strong adhesion enabled by monomer‐to‐polymer transitions. These fundamental findings provide guidance for the design of high‐performance supramolecular adhesive materials.

Small Ionic-Liquid-Based Molecule Drives Strong Adhesives.

Nature has inspired scientists to fabricate adhesive materials for applications in many burgeoning areas. However, it is still a significant challenge to develop small-molecule adhesives with high-strength, low-temperature and recyclable properties, although these merits are of great interest in various aspects. Herein, we report a series of strong adhesives based on low-molecular-weight molecular solids driven by the terminal modification of ionic liquids (ILs) and subsequent supramolecular self-assembly. The emergence of high strength and liquid-to-solid transitions for these supramolecular aggregates relies on modifying IL with a high melting point motif and enriching the types of noncovalent interactions in the original ILs. Using this strategy, we demonstrate that our IL-based molecular solids can efficiently obtain a high adhesion strength (up to 8.95 MPa). Importantly, we elucidate the mechanism underlying the reversible and strong adhesion enabled by monomer-to-polymer transitions. These fundamental findings provide guidance for the design of high-performance supramolecular adhesive materials.

Ionic Liquid‐Induced Product Switching in CO2 Electroreduction on Copper Reaction Interface

AbstractThe electrochemical reduction of CO2 (CO2RR) mainly occurs at the three‐phase interface, and the properties of an interface can directly affect the CO2RR pathway. Cu‐based materials can produce considerable amounts of alcohols and hydrocarbons, but it is hard to precisely regulate the reaction interface and obtain specific target products. Herein, the properties of the Cu surface through a facile strategy of ionic liquid modification are successfully adjusted. According to theoretical calculations and in situ Raman and FTIR spectra characterizations, it is revealed that the introduction of ionic liquids (e.g., [Bmim][PF6]) can control the energy barriers and distribution density of key intermediates on Cu interface, thus totally change the reaction pathway of CO2 electroreduction. Consequently, the dominant products from the Cu catalyst will be dramatically switched between C2H4 with a 71.1% Faraday efficiency (FE) and CH4 with a 67.2% FE. It is rarely seen in previous reports that the CO2RR products can be fundamentally changed through simple interface modifications. This work offers a straightforward approach to tune the interfacial properties and understand the mechanisms in various electrocatalytic reactions.

Characterization of a recombinant Aspergillus niger GZUF36 lipase immobilized by ionic liquid modification strategy

Enzyme immobilized on magnetic nanomaterials is a promising biocatalyst with efficient recovery under applied magnets. In this study, a recombinant extracellular lipase from Aspergillus niger GZUF36 (PEXANL1) expressed in Pichia pastoris GS115 was immobilized on ionic liquid-modified magnetic nano ferric oxide (Fe3O4@SiO2@ILs) via electrostatic and hydrophobic interaction. The morphology, structure, and properties of Fe3O4@SiO2@ILs and immobilized PEXANL1 were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, x-ray diffraction, vibration sample magnetometer, and zeta potential analysis. Under optimized conditions, the immobilization efficiency and activity recovery of immobilized PEXANL1 were 52 ± 2% and 122 ± 2%, respectively. The enzymatic properties of immobilized PEXANL1 were also investigated. The results showed that immobilized PEXANL1 achieved the maximum activity at pH 5.0 and 45 °C, and the lipolytic activity of immobilized PEXANL1 was more than twice that of PEXANL1. Compared to PEXANL1, immobilized PEXANL1 exhibited enhanced tolerance to temperature, metal ions, surfactants, and organic solvents. The operation stability experiments revealed that immobilized PEXANL1 maintained 86 ± 3% of its activity after 6 reaction cycles. The enhanced catalytic performance in enzyme immobilization on Fe3O4@SiO2@ILs made nanobiocatalysts a compelling choice for bio-industrial applications. Furthermore, Fe3O4@SiO2@ILs could also benefit various industrial enzymes and their practical uses.Key points• Immobilized PEXANL1 was confirmed by SEM, FT-IR, and XRD.• The specific activity of immobilized PEXANL1 was more than twice that of PEXANL1.• Immobilized PEXANL1 had improved properties with good operational stability.Graphical abstract

Preparation and properties of polyvinylidene fluoride dielectric nanocomposites for energy storage applications through synergistic addition of ionic liquid‐modified graphene oxide nanosheets and functionalized barium titanate hybrid fillers

AbstractTo tackle the challenge of filler agglomeration and low interfacial bonding strength during manufacturing filled polymer dielectric nanocomposites containing graphene oxide (GO) nanosheets, the author proposed an interface design strategy based on the synergistic hybridization of ionic liquid (IL) modification and different dimensional fillers. GO nanosheets were functionalized by IL, and then polyvinylidene fluoride (PVDF) dielectric nanocomposites (GO‐g‐IL/PVDF) were prepared and evaluated. Based on this, hydroxylated barium titanate BT‐OH@GO‐g‐IL/PVDF ternary nanocomposites were further prepared. A comprehensive analysis of the morphology, mechanical, thermal, electrical, and dielectric properties of the PVDF dielectric nanocomposites was systematically conducted. The results showed that IL was successfully grafted on GO, benefiting an increase in the filler dispersion and interfacial bonding strength. GO‐g‐IL also promoted β‐crystal formation of PVDF and increment of crystallinity. DSC test further revealed that the inclusion of BT‐OH@GO‐g‐IL as dielectric nanofillers promoted the formation of multiple crystal types in PVDF and accelerated the crystallization process. The incorporation of GO‐g‐IL facilitated the formation of localized conductive networks within the PVDF matrix, leading to enhanced electronic displacement polarization and an improved dielectric constant. The dielectric constants of the GO‐g‐IL/PVDF composites containing 2% and 8% of GO‐g‐IL were measured to be 24.28 and 78.46, which were found to be 2.6 and 8.4 times higher than that of pure PVDF. However, the dielectric loss also increased sharply at high nanofiller loading. The dielectric constant and loss of the BT‐OH@GO‐g‐IL/PVDF nanocomposites were found to be 40.32 and 0.38, with a content of 2% for GO‐g‐IL and 20% for BT‐OH.Highlights A facile interface design strategy based on ionic liquid (IL) integrating GO nanosheets and hydroxylated barium titanate (BT‐OH) to form BT‐OH@GO‐g‐IL compounding nanofiller has been proposed. PVDF dielectric nanocomposites containing BT‐OH@GO‐g‐IL compounding nanofiller were systematically investigated and compared. The effects of interfacial interactions between BT‐OH@GO‐g‐IL and PVDF contribute to the uniform dispersion and comprehensive property improvements of PVDF dielectric nanocomposites. This work provides a novel strategy for the fabrication of PVDF dielectric nanocomposites, inspiring the research and development of PVDF in the energy storage applications areas in the future.

Performance of ionic liquid functionalized metal organic frameworks in the adsorption process of phenol derivatives.

The growth of industrial activities has produced a significant increase in the release of toxic organic pollutants (OPs) to the environment from industrial wastewater. On this premise, this study reports the use of metal organic frameworks (MOFs) impregnated with various ionic liquids (ILs) in the adsorption of phenol derivatives, i.e., 2,6-dimethylphenol and 4,4'-dihydroxybiphenyl. MOFs were prepared starting from 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) with divalent (Co, Ni, Cu) and trivalent (Ce) metal salts in mild hydrothermal conditions using water as a green solvent. Imidazolium base ionic liquids, namely 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium nitrate, 1-butyl-3-methylimidazolium chloride, and 1-hexyl-3-methyl-imidazolium chloride, were used to modify MOFs, leading to composite materials (IL@MOF), which show the structural characteristics of MOFs, and complement the advantages of ILs. SEM, EDX images, and TG data indicate that the IL is just attached on the surface of the adsorbent material, with no changes in crystal size or morphology, but with slightly altered thermal stabilities of IL@MOF composites compared to the original ILs and MOFs, pointing to some interionic interaction between IL and MOF. This research consists of equilibrium experiments, studying the effect of the initial concentration of OPs on the adsorption efficiency of the as-prepared MOFs and IL@MOF, in order to determine the influence of the nature of the adsorbent on its developed adsorption capacity and to investigate the performance of both ILs and MOFs. To determine the maximum adsorption capacity, several empirical isotherms were used: Langmuir, Freundlich, Redlich-Peterson, and Dubinin-Radushkevich. The characteristic parameters for each isotherm and the correlation coefficient (R2) were identified. The IL modification of MOFs increased the adsorption capacity of IL@MOF for the removal of phenol derivatives from aqueous solution. The adsorption capacity function of the MOF structure follows the trend CeHEDP > CoHEDP > NiHEDP > CuHEDP. The best performance was achieved by adsorbent materials based on Ce.

Ionic liquid modification reshapes the substrate pockets of lipase to boost its stability and activity in vitamin E succinate synthesis.

The relative low stability, reusability and activity of enzymes made the industrial production of vitamin E succinate (VES) can only be performed with complex processes and high cost using chemical methods. To address these issues, in the present study, an ionic liquids (ILs) modification strategy was developed to improve the activity and stability of lipases in VES synthesis. The results showed that the [1-butyl-3-methyl imidazole] [N-acetyl-l-proline] ILs modified Candida rugosa lipase (CRL) has the highest modification degree (48.28%), activity (774 U g-1 ), thermostability and solvent tolerance in three selected modifiers. Additionally, after reaction condition optimization, the highest yield of VES can be improved to 95.18% at 45 °C for 15 h, which was significantly improved compared to some previous studies. In the present study, a high-efficiency VES synthesis strategy was successfully developed via modification of lipase. Moreover, the mechanism by which ILs modification can enhance the activity and stability of lipase was investigated via both experimental and computational-aided methods. Molecular dynamics simulation suggested that ILs modification changed the geometry of Phe344 from flat to upright, which significantly reshaped and enhanced the size of substrate binding pocket of CRL. It is also agreement with our circular dichroism and fluorescence spectroscopy results, which suggested that the modification changed the secondary structure of CRL to a certain extent. The larger pocket also endowed the suitable binding pose of succinate, which made the hydrogen bonds between succinate and active site Ser209 become stronger, and thus improving the yield of VES. © 2023 Society of Chemical Industry.

A wearable device based on the ionic liquid decorated sponge-like ultraviolet-curable resin for recognizing human mental health conditions

Developing a wearable device that can reliably and continuously detect human pulse signals and assess heart rate variability (HRV) parameters is essential for discriminating healthy subjects from patients with cardiovascular diseases and mental health disorders. Here, by combining a template-assisted ultraviolet-curing method with a subsequent ionic liquid modification, we propose a sponge-like dielectric layer and adopt it to construct a wearable device for decoding human mental health conditions. Benefiting from the coexisting sponge-like structures and an ionic liquid, the proposed wearable device presents a robust capacitance response, and could continuously monitor human pulse signals as well as analyze inter-beat intervals (IBIs) and HRV parameters of volunteers under different emotional states. Lastly, IBIs distributions and heart rates extracted from the pulse signals of the volunteers with different emotional conditions are employed as input features to train a machine-learning model, which is performed to further demonstrate the possibility of recognizing human emotions via pulse signal analysis. In conclusion, by incorporating the proposed wearable device with a machine-learning model, it is expected to achieve the emotional recognition of the volunteers with a piece of the pulse signal, showing promising potential in future human-machine interaction personalized with medical services, communications, and entertainment.

Rational Design of Porous Ionic Liquids for Coupling Natural Gas Purification with Waste Gas Conversion

AbstractRemoval of trace impurities for natural gas purification coupled with waste gas conversion is highly desired in industry. We here report a type of porous ionic liquids (PILs) that can realize the continuous flow separation of CH4/CO2/H2S and the conversion of the captured H2S to useful products. The PILs are synthesized through a step‐by‐step surface modification of ionic liquids (ILs) onto UiO‐66‐OH nanocrystals. The introduction of free tertiary amine groups on the nanocrystal surface endows these PILs with an exceptional ability to enrich H2S from CO2 and CH4 with impressive selectivity, while the permanent pores of UiO‐66‐OH act as containers to store an exceptionally higher amount of the selectively captured H2S than the corresponding nonporous ILs. Simultaneously, the tertiary amines as dual functional moieties offer effective catalytic sites for the conversion of the H2S stored in PILs into 3‐mercaptoisobutyric acid, a key intermediate required for the synthesis of Captopril (an antihypertensive drug). Molecular dynamics, density functional theory calculations and Grand Canonical Monte Carlo simulations help understand both the mechanisms of separation and catalysis performance, confirming that the tertiary amines as well as the permanent pores in UiO‐66‐OH play vital roles in the whole procedure.

Rational Design of Porous Ionic Liquids for Coupling Natural Gas Purification with Waste Gas Conversion.

Removal of trace impurities for natural gas purification coupled with waste gas conversion is highly desired in industry. We here report a type of porous ionic liquids (PILs) that can realize the continuous flow separation of CH4 /CO2 /H2 S and the conversion of the captured H2 S to useful products. The PILs are synthesized through a step-by-step surface modification of ionic liquids (ILs) onto UiO-66-OH nanocrystals. The introduction of free tertiary amine groups on the nanocrystal surface endows these PILs with an exceptional ability to enrich H2 S from CO2 and CH4 with impressive selectivity, while the permanent pores of UiO-66-OH act as containers to store an exceptionally higher amount of the selectively captured H2 S than the corresponding nonporous ILs. Simultaneously, the tertiary amines as dual functional moieties offer effective catalytic sites for the conversion of the H2 S stored in PILs into 3-mercaptoisobutyric acid, a key intermediate required for the synthesis of Captopril (an antihypertensive drug). Molecular dynamics, density functional theory calculations and Grand Canonical Monte Carlo simulations help understand both the mechanisms of separation and catalysis performance, confirming that the tertiary amines as well as the permanent pores in UiO-66-OH play vital roles in the whole procedure.

Improvement of carbon dots corrosion inhibition by ionic liquid modification: Experimental and computational investigations

Chemical modification is effective in improving the corrosion inhibition efficiency of carbon dots (CDs) on steel. Here, the imidazolium ionic liquids (IL) modified-CDs (IL-CDs) are synthesized and proved to be mixed-type corrosion inhibitors. The IL increases the pyrrole N content and facilitates the formation of a denser inhibitor film. Molecular simulations confirm that the IL reduces the π-π interaction between CDs, endowing IL-CDs with higher water solubility and better corrosion inhibition effect than CDs. The lower orbital energy gap and larger positive electrostatic potential distribution enable the inhibition efficiency of IL-CDs of 97.11% in 1 M HCl, much superior to CDs (90.80%).

Preparation of Composite Single‐Ion Conductor Membrane and Its Application in Lithium–Oxygen Battery

Redox mediators (RMs) are reported to effectually encourage the inactive decomposition of discharge products in lithium–oxygen batteries (LOBs); however, oxidized RMs and other injurious species still attack the Li anodes. An ionic liquid (IL)‐modified PVDF single‐lithium‐ion conducting composite membrane that can permit Li+ only but blocks anions and other molecules is prepared. The PVDF is combined with the strong‐acid cation styrene exchange resin with cation exchange characteristics to make a heterogeneous composite single‐ionic conductor membrane and the IL modification causes the formation of a more‐dense groove inside the PVDF membrane apparently strengthening the conductivity of the membrane without losing its impermeability to cations and discharge intermediates. The utility of the modified composite PVDF (MCP) separator greatly extends the cycle life of the LOB from 66 to 347 cycles at 1000 mAg−1 and 1000 mAhg−1 compared to cells using glass fiber separators. Rate performance is significantly enhanced at 3000 and 5000 mAg−1, increasing from 33 and 21 cycles to 171 and 137 cycles. The full discharge capacity also expands from 3702 to 51 205 mAhg−1. The MCP separator enables iodide‐assisted cathode processes and improves lithium anode stripping/plating, which is essential to improve the performance of nonelectrolytic LOBs.

Enhanced stability and catalytic performance of laccase immobilized on magnetic graphene oxide modified with ionic liquids

Graphite oxide (GO) is an excellent laccase immobilization material. However, the electrostatic interaction between graphene leads to the accumulation of GO, as well as the interaction with the surface of enzyme molecules causing protein denaturation and deactivation, which limits its further industrial application. In this study, the ionic liquids (ILs) modification strategy was proposed to improve the stability and catalytic performance of immobilized laccase. The laccase-ILs-MGO exhibited remarkable enzymatic properties, with significant enhancements in organic solvent tolerance, thermal and operational stability. The laccase-ILs-MGO system exhibited a remarkable removal efficiency of 95.5% towards 2,4-dichlorophenol (2,4-DCP) within 12 h and maintained over 70.0% removal efficiency after seven reaction cycles. In addition, the efficient elimination of other phenolic compounds and recalcitrant polycyclic aromatic hydrocarbons could also be accomplished. Molecular dynamics simulation and molecular docking studies demonstrated that immobilized laccase exhibited superior structural rigidity and stronger hydrogen bond interactions with substrates compared to free laccase, which was beneficial for the stability of both the laccase and substrate degradation efficiency. Therefore, this study proposed a simple and practical strategy for modifying GO with ILs, providing novel insights into developing efficient enzyme immobilization techniques.

Synergistic Effect of 2D ZIF Loading and Ionic Liquid Modification on Improving Gas Separation Performance of PES-Based Mixed Matrix Hollow Fiber Membrane

Synergistic Effect of 2D ZIF Loading and Ionic Liquid Modification on Improving Gas Separation Performance of PES-Based Mixed Matrix Hollow Fiber Membrane

Ag nanoparticle-modified P-doped tubular g-C3N4 for enhanced degradation of organic pollutants

Ag-doped ionic liquids (ILs) modified tubular g-C3N4 was prepared by hydrothermal, thermal polymerization and photoreduction method (Ag/PILCN). The ILs modification of g-C3N4 greatly increases its specific surface area and introduces P elements, which not only provides good conditions for the attachment of Ag nanoparticles at a later stage, but also increases the catalytic reaction sites and improves the final photocatalytic performance. Compared with pure g-C3N4, the synergistic effect of ILs surface modification and Ag doping in Ag/PILCN greatly enhanced the photocatalytic degradation ability of Ag/PILCN. The internal degradation efficiency of tetracycline reached 96.4%, and the catalytic performance did not decrease significantly after four cycles.