Cation Anion Research Articles

Structural and Dynamic Characterization of Li–Ionic Liquid Electrolyte Solutions for Application in Li-Ion Batteries: A Molecular Dynamics Approach

Pyrrolidinium-based (Pyr) ionic liquids (ILs) have been proposed as electrolyte components in lithium-ion batteries (LiBs), mainly due to their higher electrochemical stability and wider electrochemical window. Since they are not naturally electroactive, in order to allow their use in LiBs, it is necessary to mix the ionic liquids with lithium salts (Li). Li–PF6, Li–BF4, and Li–TFSI are among the lithium salts more frequently used in LiBs, and each anion, namely PF6 (hexafluorophosphate), BF4 (tetrafluoroborate), and TFSI (bis(trifluoromethanesulfonyl)azanide), has its own solvation characteristics and interaction profile with the pyrrolidinium ions. The size of Pyr cations, the anion size and symmetry, and cation–anion combinations influence the Li-ion solvation properties. In this work, we used molecular dynamics calculations to achieve a comprehensive view of the role of each cation–anion combination and of different fractions of lithium in the solutions to assess their relative advantage for Li-ion battery applications, by comparing the solvation and structural properties of the systems. This is the most-comprehensive work so far to consider pyrrolidinium-based ILs with different anions and different amounts of Li: from it, we can systematically determine the role of each constituent and its concentration on the structural and dynamic properties of the electrolyte solutions.

Guanidinium cationic covalent organic nanosheets-based anion exchange composite membrane for fuel cells

Covalent organic frameworks (COFs) used for anion exchange membrane fuel cells (AEMFCs) are commonly endowed with ion conductivity by post-synthesis modification. However, this method usually results in uneven distribution of functional groups, low functionalization and severe ion capacity fade. Limited by hydrophobic skeleton and relatively large particle size of COFs, the COFs doping amount of the composite membrane is not high. Here we design and synthesize a series of guanidinium cationic covalent organic nanosheets-based anion exchange composite membranes. The positively charged guanidinium group as a building block can induce COF-DhaTGCl self-exfoliation into a few layered nanosheets through strong interlayer repulsion. Then, the nanosheets were introduced into quaternary ammonium-functionalized poly(2,6-dimethyl-1,4-phenyl ether) (QPPO). A series of COF-DhaTGCl/PPO composite AEMs was prepared with the highest doping amount of 30 wt% by casting method. The porous structure and repeat cationic guanidinium units on the skeleton will expose ion sites to the target ones, providing faster OH− diffusion kinetics in one-dimensional channels. The OH− conductivity of COF-DhaTGCl/PPO-20 composite membrane can reach 148.65 mS/cm at 80 °C. Meanwhile, the composite membrane also exhibits enhanced mechanical strength and alkaline stability with the maximum stress strength of 37.3 MPa and the residual conductivity of 96.29% after immersion in 2 M NaOH solution at 60 °C for two weeks.

Negative dietary cation–anion difference in prepartum dairy cow diets: a pragmatic study in two commercial dairy farms

Pragmatic studies, evaluating the effectiveness of an intervention under its usual conditions, are less commonly reported than the explanatory trials. For instance, the effectiveness of prepartum negative dietary cation-anion difference (DCAD) diets on inducing a compensated metabolic acidosis that promotes a higher blood Ca concentration at calving has not been frequently described under commercial farm management conditions without researchers' interference. Thus, the objectives were to study cows under commercial farm management conditions to (1) describe the daily close-up dairy cows' urine pH and fed DCAD, and (2) evaluate the association between urine pH and fed DCAD, and preceding urine pH and blood Ca at calving. A total of 129 close-up Jersey cows about to commence their ≥2nd lactation were enrolled in the study after 7 days of exposure to DCAD diets in two commercial dairy herds. Urine pH was determined daily from mid-stream urine samples from enrollment to calving. Fed DCAD was determined from feed bunk samples obtained during 29 (Herd 1) and 23 (Herd 2) consecutive days. Plasma Ca concentration was determined within 12 h after calving. Descriptive statistics were generated at the herd- and cow-level. Multiple linear regression was used to evaluate the associations between urine pH and fed DCAD for each herd, and preceding urine pH and plasma Ca concentration at calving for both herds. At herd-level, the average urine pH and CV during the study period were 6.1 and 12.0% (Herd 1) and 5.9 and 10.9% (Herd 2), respectively. At the cow-level, the average urine pH and CV during the study period were 6.1 and 10.3% (Herd 1) and 6.1 and 12.3% (Herd 2), respectively. During the study period, fed DCAD averages were -121.3 and -165.7 mEq/kg of DM and CV 22.8 and 60.6% for Herd 1 and Herd 2, respectively. No evidence of association between cows' urine pH and fed DCAD was observed in Herd 1, whereas a quadratic association was observed in Herd 2. When both herds were combined, a quadratic association was observed between the urine pH intercept (at calving) and plasma Ca concentration. Although average urine pH and fed DCAD were within recommended ranges, the high variability observed indicates that acidification and fed DCAD are not constant, and often outside the recommended ranges in commercial settings. Monitoring of DCAD programs is warranted to ensure their effectiveness under commercial settings.

Experimental and DFT Studies on Electrochemical Performances of Ester-Containing Vinylimidazolium Ionic Liquids: Effect of the Ester Substituent and Anion

Four imidazolium ionic liquids (ILs) with vinyl and ester groups were synthesized and characterized by 1H NMR, 13C NMR, and element analysis. The refractive index, electrical conductivity (EC), and electrochemical stability window (ESW) of the ILs were determined. The effect of the alkyl chain length of the ester group and anions on electrochemical properties was analyzed by density functional theory (DFT) calculations. At the same temperatures, the EC of the ILs decreased with the increase of the alkyl chain length. The ester group and vinyl group of cations showed a negative effect on the EC. The ESW increased with the increase of the alkyl chain length. The introduction of the ester group and vinyl group decreased the cathodic limiting potential of ester-based vinylimidazolium cations. DFT simulations showed that the structure of the IL was closely related to the EC and ESW. The average hydrogen bond length increased with the increase of the alkyl chain length of the ester group. The absolute interaction energy of ILs decreased with the increase of the alkyl chain length. Introduction of the vinyl group and ester group into the imidazolium cation resulted in a stronger cation–anion interaction, strengthening the ion mobility and charge transfer, resulting in a lower EC. The information is useful for the design and optimization of ILs as electrolytes for energy storage applications.

Designing Zwitterionic Gel Polymer Electrolytes with Dual‐Ion Solvation Regulation Enabling Stable Sodium Ion Capacitor

AbstractSodium ion capacitors (SICs) show high energy/power densities owing to the special dual‐ion energy storage mechanism with cation intercalation and anion adsorption. However, the strong ion‐solvent interactions make it difficult for interfacial ion desolvation, which not only limits the ion transport kinetics, but also results in the solvent co‐intercalation into electrode materials. Here, an advanced zwitterionic gel polymer electrolyte (GPE) is developed to weaken the ion‐solvent interactions. The 3‐(1‐vinyl‐3‐imidazolio) propanesulfonate (VIPS) zwitterions help to lower the desolvation barriers, enabling fast ion transfer kinetics for constructing stable quasi‐solid‐state SICs. Furthermore, the decomposition of VIPS contributes to the formation of S‐ and N‐based inorganic interphase on the surface of hard carbon anode, which reduces the Na+ ion diffusion barriers and improves electrochemical compatibility. The designed Zwitterionic GPE can stabilize 4.0 V hard carbon//activated carbon SICs with 95.3% capacity retention after 9000 cycles, showing a high energy density of 140.2 Wh kg−1. This study highlights the regulation of ion‐solvent chemistry and provides a guiding principle in electrolyte design for advanced hybrid ion capacitors.

Multiphysics factor facilitating fast reaction kinetics for high-power-density Li–Se batteries

An intriguing multiphysics factor for facilitating fast reaction kinetics is proposed herein to achieve high-power-density cathodes for lithium-selenium batteries (LSeBs) based on Se and Te-doped cathode models from the perspective of thermodynamic, chemical, and Li kinetics. Compared with the bare electrode, the optimized Te–Se electrode showed a much greater rate capability under harsh conditions in balancing the theoretical capacity and improving the redox kinetics. This fast kinetic property is understood in detail by cyclic voltammetry analysis, and a reduction in the electrochemical polarization, depending on the increase in the scan rate, is observed for the Te–Se electrode. In addition, the voltage hysteresis of the Se cathode increased rapidly in the C-rate mode, whereas that of the Te–Se electrode increased at a much slower rate. Therefore, a comparison of intrinsic thermodynamic hysteresis is performed to highlight the difference between the Se-based electrodes, and the reaction resistance and Li diffusion coefficient for the Te–Se cathode from the kinetic point of view are found to exhibit a superior feature during (dis)charging. The theoretical results are broken down into three perspectives: i) thermodynamics, ii) electronic structure, and iii) Li kinetics, systematically elucidating the fast kinetics of the Te-doped Se cathode compared to the pristine material. Lowering the formation energy, increasing the electronic population, and loosening the cation–anion bond are simultaneously triggered by Te doping, and their combined effects are deemed to be a multiphysics factor. The concrete experiment and computational understanding confirm the high power density of the Te–Se electrode relative to the reference model upon long-term cycling, and validate that the multiphysics factors pose a potentially global design strategy to enable fast kinetics for achieving high-performance LSeBs, even lithium-sulfur batteries.

The closed-loop recycling strategy of Li and Co metal ions based on aqueous Zn-air desalination battery

Nowadays, it is a global problem to recycle LiCoO2 from waste lithium-ion batteries (LIBs) due to the deficiency of high business cost and environmental pollution. Here, a novel three-channel ion recovery device based on a Zn-air desalination battery (ZADB) is proposed which can supply energy while separating Li+ and Co2+ from the recovered solution. The three-channel ZADB device consists of a Zn foil anode chamber with ZnSO4 anolyte stream, an intermediate chamber with Li+ and Co2+ recovered stream and an air cathode chamber with LiOH and Co(OH)2 catholyte stream, chambers are separated by anion exchange membrane (AEM) and cation exchange membrane (CEM) respectively. It can be described by the finite element simulation (FES) of physics field that, the Li+ and Co2+ in the recovered solution move to the cathode chamber, where the OH− are produced by absorbing O2 from the air combined with electronic in the discharge process. At the same time, the SO42− moves to the other end of the Zn foil anode chamber according to the law of charge conservation, which combined with the Zn2+ removed from the Zn foil. The results show that the recovery efficiency of the ZADB device is closely related to the discharge current density and the concentration of the recovered stream. The best recovery effect has achieved when 0.2 mol L−1 recovered solution is run for 24 h at the discharge current density of 0.2 mA cm−2. The average recovery rate is 0.275 mg min−1 with the highest recovery rate is 40.73 mg h−1, and the output energy density is 102.5 Wh Kg−1 during the experiment process. In addition, the ZADB device has the excellent long-term cycling performance and recycling stability. By comparing this device with other ion recovery methods, which provides that it is a splendid way to recycle Li+ and Co2+ from waste LIBs.

A Heptacene Analogue Entailing a Quinoidal Benzodi[7]annulene (7/6/7 Ring) Core with a Tunable Configuration and Multiple Redox Properties.

Non-benzenoid acenes containing heptagons have received increasing attention. We herein report a heptacene analogue containing a quinoidal benzodi[7]annulene core. Derivatives of this new non-benzenoid acene were obtained through an efficient synthetic strategy involving an Aldol condensation and a Diels-Alder reaction as key steps. The configuration of this heptacene analogue can be modulated from a wavy to a curved one by just varying the substituents from a (triisopropylsilyl)ethynyl group to a 2,4,6-triisopropylphenyl (Trip) group. When mesityl (Mes) groups are linked to the heptagons, the resulting non-benzenoid acene displays polymorphism with a tunable configuration from a curved to a wavy one upon varying the crystallization conditions. In addition, this new non-benzenoid acene can be oxidized or reduced by NOSbF6 or KC8 to the respective radical cation or radical anion. Compared with the neutral acene, the radical anion shows a wavy configuration and the central hexagon becomes aromatic.

A Heptacene Analogue Entailing a Quinoidal Benzodi[7]annulene (7/6/7 Ring) Core with a Tunable Configuration and Multiple Redox Properties

AbstractNon‐benzenoid acenes containing heptagons have received increasing attention. We herein report a heptacene analogue containing a quinoidal benzodi[7]annulene core. Derivatives of this new non‐benzenoid acene were obtained through an efficient synthetic strategy involving an Aldol condensation and a Diels–Alder reaction as key steps. The configuration of this heptacene analogue can be modulated from a wavy to a curved one by just varying the substituents from a (triisopropylsilyl)ethynyl group to a 2,4,6‐triisopropylphenyl (Trip) group. When mesityl (Mes) groups are linked to the heptagons, the resulting non‐benzenoid acene displays polymorphism with a tunable configuration from a curved to a wavy one upon varying the crystallization conditions. In addition, this new non‐benzenoid acene can be oxidized or reduced by NOSbF6 or KC8 to the respective radical cation or radical anion. Compared with the neutral acene, the radical anion shows a wavy configuration and the central hexagon becomes aromatic.

Fe-doping-induced cation substitution and anion vacancies promoting Co3O4 hexagonal nanosheets for efficient overall water splitting

Water electrolysis is a green technology for hydrogen fuel production, but greatly hampered by the slow kinetics of the anodic oxygen evolution reaction (OER) and the cathodic hydrogen evolution reaction (HER). In this work, we report an efficient strategy to simultaneously promote OER and HER performance on Co3O4 hexagonal nanosheets via Fe-doping-induced cation substitution and anion vacancies. Benefiting from the integrated advantages of well-defined ultrathin nanosheets, abundant vacancies, and unique three-dimensional electrode configuration, the optimized Fe-doped Co3O4 hexagonal nanosheets/nickel foam (Fe0.4Co2.6O4 HNSs/NF) can achieve overpotentials of 328 mV at 100 mA cm−2 for OER and 315 mV at 500 mA cm−2 for HER, respectively, which is comparable to those of the benchmark noble electrocatalysts. More importantly, the Fe0.4Co2.6O4 HNSs/NF-assembled electrolyzer for overall water splitting can deliver a current density of 100 mA cm−2 at a cell voltage as low as 1.66 V and work steadily at 50 mA cm−2 with a negligible fading up to 140 h.

Effects of Fe occupancy on physical properties of non-magnetic GeGa2O4 spinel oxide

This study investigated the structural, elastic, electronic, thermal, magnetic, and optical behavior of GeGa2O4, FeGa2O4, GeFe2O4, and FeFe2O4 spinel oxides based on ab-initio calculations. The results showed that the non-magnetic spinel oxide GeGa2O4 exhibited remarkable physical properties due to Fe occupancy at different lattice sites within the spinel lattice. The Fe containing spinel oxides (FeGa2O4, GeFe2O4, and FeFe2O4) were found to be stable in the magnetic phase in contrast to the host GeGa2O4 spinel oxide. The spin polarizations of FeGa2O4, GeFe2O4, and FeFe2O4 oxides were calculated as 98.5%, 98.4%, and 100%, respectively. Analysis of the elastic and mechanical properties showed that all of the spinel oxides followed the Born and Huang criteria for mechanical stability. The highest Debye temperature (θD = 663.77 K) was determined for the FeGa2O4 spinel oxide. For GeGa2O4, FeGa2O4, GeFe2O4, and FeFe2O4 oxides, the calculated structural parameters (cation–anion bond lengths and average values of tetrahedral and octahedral radii) predicted the following cation distributions among the A and B atomic sites: (Ge2+)[Ga23+]O4−2, (Fe2+)[Ga23+]O4−2, (Ge4+)[Fe22+]O4−2, and (Fe+2)[Fe23+]O4−2. The calculated electronic structures indicated that the host GeGa2O4 spinel oxide and FeFe2O4 spinel ferrite were semi-conducting and half-metallic ferromagnetic, respectively, whereas FeGa2O4 and GeFe2O4 oxides exhibited semi-metallic behavior. The GeFe2O4 spinel oxide was found to have the highest saturation magnetization (185.79 emu g−1) and total magnetic moment (8.26 ΣBfu−1). The calculated optical properties indicated the suitability of these oxides for use in optical filters and sensors. The electronic and magnetic characteristics of these spinel oxides with excellent thermal and elastic stability suggest that they have potential uses in diluted magnetic semiconductor devices.

Current status of CO2 capture with ionic liquids: Development and progress

Global warming triggered by greenhouse gas (GHG) emissions, particularly carbon dioxide (CO2), significantly influences climate change and has become a common environmental issue recently. The current amine-based technologies (ABTs) for CO2 capture (CAPCO2) have high energy demand, low absorption, and desorption rates, and are less environmentally sustainable due to high emissions of volatile solvents. Therefore, the development of environmentally friendly CAPCO2 materials and/or processes is a growing area of research. The utilization of ionic liquids (ILs) for CAPCO2 has recently attracted attention. The unique characteristics of ILs, such as their low vapor pressure and high affinity for CAPCO2 as well as their low volatility make them a viable substitute for the existing processes. This work provides a comprehensive overview of the accomplishments and challenges during the use of ILs for CAPCO2. The Review also outlines the mechanisms of the CAPCO2 with ILs at the molecular level, the properties of ILs, characterization of the CO2/IL systems, and the effect of operating conditions on CO2 uptake (UPCO2) capacity by ILs. It also emphasizes the impact of cations, anions, and functional groups on the solubility of CO2 ((SCO2)) in ILs as well as the biodegradability and toxicity of ILs. Additionally, recent advances in IL membrane technology for the CAPCO2 processes are considered. Lastly, the contribution of molecular simulations to create and assess ILs was reviewed. Protic and aprotic ILs properties have shown outstanding efficiency of UPCO2. The interactions between the anionic part of IL and CO2 enhance the UPCO2 and outperform the efficiency of traditional organic solvents. Functionalized ionic liquids (FUNILs) with tuned functional groups, supported ionic liquids membranes (SILMs) as well as reversible ionic liquids (RILs) have improved the efficiency of ILs as a promising CO2 capturing process from industrial streams even under low CO2 partial pressure. The relative importance of the chemical breakdown of the IL constituents (cation–anion interfacial structuring) during the CAPCO2 process at different operating temperatures is unclear, and more research in this area is required to better inform the design of new ILs. This review provides a proper/systematic guideline to help ILs manufacturers and engineers design high-capacity ILs for appropriate CAPCO2.

Quadripartite bond length rule applied to two prototypical aromatic and antiaromatic molecules

ContextIn 2000, a remarkably simple relationship was introduced, which connected the calculated geometries of isomolecular states of three different multiplicities. These encompass a ground single state, the first excited triplet state, as well as related radical anion and radical cation. The rule allows the prediction of the geometry of one of the species if the three remaining ones are known. Here, we verify the applicability of this bond length rule for two small planar cyclic organic molecules, i.e., benzene and cyclobutadiene, which stand as prototypical examples of, respectively, aromatic and antiaromatic systems. We see that the rule works fairly well to benzene, and it works independently for quinoid as well as for anti-quinoid minima, despite the fact that radical anion species poses challenges for correct theoretical description.MethodsTo obtain chosen electronic state equilibrium geometries, three types of computational approaches were utilized: fast and efficient density functional theory DFT, the coupled cluster method CC2, the complete active space self-consistent field (CASSCF) approach, and the most accurate but also resource-consuming perturbation theory with multireference wavefunction (CASPT2) with a default value and without IPEA-shift. Dunning and co-workers correlation-consistent basis sets (aug-)cc-pVXZ (X = D, T, Q) were employed. Gaussian 16 revision A.03, Turbomole 7.1, and Molcas 8.0 computational software were used.

Comparative Studies on Effects of Metal Cation (La) and Non-Metal Anion (N) Doping on CeO2 Nanoparticles for Regenerative Scavenging of Reactive Oxygen Radicals

The intrinsic effects of metal cation (La) and non-metallic anion (N) doping of CeO2 nanoparticles (NPs) for regenerative scavenging of reactive oxygen radicals were studied. La-doped CeO2 NPs were prepared by the conventional impregnation method at various La doping levels. N-doped CeO2 NPs were prepared by urea thermolysis with two different methods: (i) direct thermolysis of urea after physical mixing with CeO2 NPs and (ii) wet impregnation of CeO2 NPs with urea followed by thermolysis under inert N2 atmosphere. Physicochemical properties of samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, and N2 sorption measurement. Radical scavenging properties of the samples were characterized by applying Fenton’s reaction. Results indicated that atomic N doping on CeO2 NPs significantly enhanced radical scavenging properties of CeO2 NPs, resulting in an activity of N-doped CeO2 about 3.6 times greater than the pristine CeO2 NPs and 1.6 times higher than the La-doped CeO2 NPs. This result suggests that anionic N doping of CeO2 NPs is highly effective in enhancing radical scavenging properties of CeO2 NPs, whereas such modifications have been typically practiced by hetero-metal doping with rare earth metal elements. A collective structure–property correlation analysis suggested that enhancement of radical scavenging properties of heteroatom-doped CeO2 NPs was largely attributed to an increase in surface oxygen vacancies on CeO2 NPs due to heteroatom doping.

Suppression of anthracite dust by a composite of oppositely-charged ionic surfactants with ultra-high surface activity: Theoretical calculation and experiments

In this study, we developed composite anionic–cationic (AC) surfactants with ultra-high surface activity using sodium alpha olefin sulfonate and octadecyltrimethylammonium chloride to improve the wettability and dust suppression efficiency of coal dust. Moreover, we investigated the synergistic suppression mechanisms of AC surfactant compounds at a molecular level. The thermodynamics of the self-assembly suggested that the surfactant molecules in the composite solution form a flexible alternating anion–cation bilayer. The analysis of the critical micelle concentration (CMC), surface tension (24.121 mN·m−1), contact angle (35.14°) and settling time (18 s) of the composite surfactant solution proved the superior performance of our composite surfactants compared to the monomeric alternatives, resulting in enhanced wettability owing to an ultra-high surface activity. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) experiments revealed an increased number of hydrophilic groups on the surface of the composite surfactant-treated anthracite, explaining the microscopic mechanism behind the high wettability induced by the composite surfactant. The specific surface area and pore size distribution of anthracite before and after dust suppressant treatment were calculated, and it was concluded that the dust suppressant was adsorbed on the surface and in the pores of the anthracite. In addition, the microscopic external morphology of the anthracite was shown by scanning electron microscopy (SEM), and it was found that the dust suppressant showed filling and aggregation behavior. Wind erosion and evaporation resistance experimental results show that dust suppressant-treated coal dust has enhanced water retention and wind resistance. Our findings indicate that ionic surfactants with oppositely charged compounds are promising high-efficiency dust suppressants, laying the foundation for safe coal mining and providing a theoretical background for a broad range of applications, such as haze control.

Switchable Dielectric Materials Based on a Diprotonated Organic Cation Containing Two Different Anions: (C5H16N2)BF4X (X = Cl, Br, NO3)

Three molecular-based phase transition compounds, namely, (C5H16N2)BF4Cl (1, C5H16N2 = diprotonated 2,2-dimethyl-1,3-propanediamine), (C5H16N2)BF4Br (2), and (C5H16N2)BF4NO3 (3), were synthesized and characterized. Differential scanning calorimetry and the step-like anomaly of the real part (ε′) of the temperature-dependent dielectric constant revealed that the compounds underwent reversible first-order phase transition with high phase transition temperature under the stimulation of temperature. Variable-temperature X-ray diffraction analysis revealed that the microcosmic driving force of phase transition was the order–disordered change of the organic cation and spherical anion. Notably, the diprotonated organic cations were charge-balanced by two different anions of the combination BF4– and Cl–, Br– and NO3–. Our research paves a new avenue to construct molecular-based phase transition materials with temperature stimulus response.

Ionic Liquid-Based Green Emulsion Liquid Membrane for the Extraction of the Poorly Soluble Drug Ibuprofen

Ibuprofen (Ibf) is a biologically active drug (BADs) and an emerging contaminant of concern (CECs) in aqueous streams. Due to its adverse effects upon aquatic organisms and humans, the removal and recovery of Ibf are essential. Usually, conventional solvents are employed for the separation and recovery of ibuprofen. Due to environmental limitations, alternative green extracting agents need to be explored. Ionic liquids (ILs), emerging and greener alternatives, can also serve this purpose. It is essential to explore ILs that are effective for recovering ibuprofen, among millions of ILs. The conductor-like screening model for real solvents (COSMO-RS) is an efficient tool that can be used to screen ILs specifically for ibuprofen extraction. The main objective of this work was to identify the best IL for the extraction of ibuprofen. A total of 152 different cation-anion combinations consisting of eight aromatic and non-aromatic cations and nineteen anions were screened. The evaluation was based upon activity coefficients, capacity, and selectivity values. Furthermore, the effect of alkyl chain length was studied. The results suggest that quaternary ammonium (cation) and sulfate (anion) have better extraction ability for ibuprofen than the other combinations tested. An ionic liquid-based green emulsion liquid membrane (ILGELM) was developed using the selected ionic liquid as the extractant, sunflower oil as the diluent, Span 80 as the surfactant, and NaOH as the stripping agent. Experimental verification was carried out using the ILGELM. The experimental results indicated that the predicted COSMO-RS and the experimental results were in good agreement. The proposed IL-based GELM is highly effective for the removal and recovery of ibuprofen.

CO2 Adsorption Based on Porphyrin Based Porous Organic Polymers

In order to efficiently catalyze the cycloaddition reaction of CO2 and epoxy alkanes under mild environment and no catalyst, this paper designed and synthesized two kinds of porphyrin based porous organic polymers—porphyrin based porous organic polymer containing carboxyl group (ppop-cooh) and porphyrin based porous organic polymer containing quaternary ammonium salt ion pair. Quaternary ammonium salt cation anion pair nucleophilic groups and metal active centers were introduced into the polymer by pre- and post-modification respectively. The chemical structure and pore structure of the polymer were characterized by infrared spectroscopy and physical adsorption instrument, and its effect as a catalyst on the cycloaddition reaction of CO2 and epoxy alkanes was studied. From the results, it is demonstrated that the two polymers had a multistage pore structure with a specific surface area of 302 m2/g-514 m2/g. The synergistic effect of Lewis acid metal ions, nucleophiles and multistage pore structure in the polymer significantly promotes the cycloaddition reaction between CO2 and epoxy alkanes. Under mild conditions (80°C, 0.3 MPa, 24h), the selectivity and conversion of the reaction reach more than 99%. The polymer is repeated for many times. After use, it still has good catalytic performance.

Epigenetics and stroke: role of DNA methylation and effect of aging on blood–brain barrier recovery

Incomplete recovery of blood–brain barrier (BBB) function contributes to stroke outcomes. How the BBB recovers after stroke remains largely unknown. Emerging evidence suggests that epigenetic factors play a significant role in regulating post-stroke BBB recovery. This study aimed to evaluate the epigenetic and transcriptional profile of cerebral microvessels after thromboembolic (TE) stroke to define potential causes of limited BBB recovery. RNA-sequencing and reduced representation bisulfite sequencing (RRBS) analyses were performed using microvessels isolated from young (6 months) and old (18 months) mice seven days poststroke compared to age-matched sham controls. DNA methylation profiling of poststroke brain microvessels revealed 11,287 differentially methylated regions (DMR) in old and 9818 DMR in young mice, corresponding to annotated genes. These DMR were enriched in genes encoding cell structural proteins (e.g., cell junction, and cell polarity, actin cytoskeleton, extracellular matrix), transporters and channels (e.g., potassium transmembrane transporter, organic anion and inorganic cation transporters, calcium ion transport), and proteins involved in endothelial cell processes (e.g., angiogenesis/vasculogenesis, cell signaling and transcription regulation). Integrated analysis of methylation and RNA sequencing identified changes in cell junctions (occludin), actin remodeling (ezrin) as well as signaling pathways like Rho GTPase (RhoA and Cdc42ep4). Aging as a hub of aberrant methylation affected BBB recovery processes by profound alterations (hypermethylation and repression) in structural protein expression (e.g., claudin-5) as well as activation of a set of genes involved in endothelial to mesenchymal transformation (e.g., Sox9, Snai1), repression of angiogenesis and epigenetic regulation. These findings revealed that DNA methylation plays an important role in regulating BBB repair after stroke, through regulating processes associated with BBB restoration and prevalently with processes enhancing BBB injury.

Size Effect of Electrolyte Ions on the Electric Double-Layer Structure and Supercapacitive Behavior

Finding a viable electrolyte for next-generation supercapacitors is of primary importance for developing supercapacitors with high power and energy densities. Herein, we synthesized a conducting salt, tetramethylphosphonium tetrafluoroborate (TMPBF4), and compared the electrochemical characteristics of supercapacitor devices containing TMPBF4 or 1,1-dimethylpyrrolidinium tetrafluoroborate (DMPBF4). The TMPBF4 salt was selected based on the generally accepted design rule that smaller ions and solvation shells contribute to higher energy and power densities. However, at a low current density (0.1 A g–1), supercapacitors with TMPBF4 in acetonitrile (AN) exhibited a slightly lower capacitance (24.6 ± 0.1 F g–1) than those with DMPBF4 (25.0 ± 0.2 F g–1). Clarification of this behavior using electrochemical and theoretical methods revealed that the total capacitance is influenced by not only the size of the ions but also the degree of cation–anion interactions near the electrodes. By contrast, at a high current density of 10 A g–1, supercapacitors with TMPBF4 showed an 18% increase in capacitance relative to those with DMPBF4. Supercapacitors with TMPBF4 exhibited both high capacitance and a remarkably long cycle life (10,000 cycles) at a high working voltage (3.2 V) and high current density (10 A g–1). Furthermore, supercapacitors utilizing TMPBF4/AN provided a sufficiently fast frequency response for 60 Hz alternating current (ac) line filtering. These insights into the influence of the investigated electrolyte salts on the formation of electric double-layer structures offer design rules for developing electrolytes for supercapacitors.