Effect Of Anion Species Research Articles

Influence of Inorganic Anions on the Chemical Stability of Molybdenum Disulfide Nanosheets in the Aqueous Environment.

Chemical stability is closely associated with the transformations and bioavailabilities of engineered nanomaterials and is a key factor that governs broader and long-term application. With the growing utilization of molybdenum disulfide (MoS2) nanosheets in water treatment and purification processes, it is crucial to evaluate the stability of MoS2 nanosheets in aquatic environments. Nonetheless, the effects of anionic species on MoS2 remain largely unexplored. Herein, the stability of chemically exfoliated MoS2 nanosheets (ceMoS2) was assessed in the presence of inorganic anions. The results showed that the chemical stability of ceMoS2 was regulated by the nucleophilicities and the resultant charging effects of the anions in aquatic systems. The anions promote the dissolution of ceMoS2 by triggering a shift in the chemical potential of the ceMoS2 surface as a function of the anion nucleophilicity (i.e., charging effect). Fast charging with HCO3- and HPO42-/H2PO4- was validated by a phase transition from 1T to 2H and the emergence of MoV, and it promoted oxidative dissolution of the ceMoS2. Additionally, under sunlight, ceMoS2 dissolution was accelerated by NO3-. These findings provide insight into the ion-induced fate of ceMoS2 and the durability and risks of MoS2 nanosheets in environmental applications.

Effect of anion species on preparation and properties of pitch-based activated carbon fibers by in-situ catalytic activation of metal nanoparticles

Effect of anion species on preparation and properties of pitch-based activated carbon fibers by in-situ catalytic activation of metal nanoparticles

Lubrication by Adsorption Films of Hydrophilic Amine-based Protic Ionic Liquids: Effect of Anion Species.

In this study, we synthesize hydrophilic amine-based protic ionic liquids (PILs) with hydroxy groups in a cation and different anions. Subsequently, we evaluate the kinetic friction coefficients of iron oxide in aqueous solutions of the PILs under different sliding conditions. Ditriethanolamine malate, triethanolamine lactate, triethanolamine methoxyacetate, and triethanolamine acetate are used as PIL samples in this study. Among them, ditriethanolamine malate exhibits the lowest kinetic friction coefficient. As the number of sliding cycles increases, the excellent lubrication capability remains. Subsequently, we characterize the adsorption of the PILs on an iron oxide surface to investigate the lubrication behavior on the basis of quartz crystal microbalance with dissipation monitoring and force curve data. We expect hydrophilic PILs to be excellent water-soluble lubricants and additives for use in metal surface treatments.

(A04 Best Poster Award Winner) Effects of Anion Species on Li Ion Transport and Electrochemical Properties in Highly Concentrated Electrolytes

Highly concentrated solutions of Li salt dissolved in polar solvents have various attractive features as battery electrolytes.1 Recently, our group reported that Li+ ion hopping conduction occurs in highly concentrated electrolytes of Li-salt/sulfolane (SL) where Li+ ion diffuses faster than anions and SL.2,3 In the liquids of high concentration Li-salt/SL electrolytes, the polymeric network structures of Li+−SL−Li+ and Li+−anion−Li+ are formed, and Li+ ion hops from one coordination site to another through the ligand exchange. Similar Li+ ion hopping conduction was also observed for highly concentrated electrolytes with certain solvents having multiple coordinating sites, such as keto ester,4 dinitrile,5 and other sulfone solvents.6 We report here the effects of anion species on the transport properties (ionic conductivity (σ) and viscosity (η)) and the battery performance of the highly concentrated electrolytes composed of SL and Li-salts, LiBF4, LiN(SO2CF3)2 (LiTFSA), and LiN(SO2F)2 (LiFSA). The order of molar ionic conductivity (σ/c Li+) is LiFSA > LiBF4 ⋍ LiTFSA. Li+ ion transference number (t Li+) under anion-blocking conditions was estimated using a symmetric Li/Li cell. The order of t Li+ values in the SL-based electrolytes is LiBF4 > LiTFSA > LiFSA, suggesting that the Lewis basicity of the anions and the Li+−anion association affect the Li+ ion transport in the highly concentrated electrolytes. To investigate the effects of anion species on the battery performance, we conducted charge-discharge tests of Li–graphite cells with these electrolytes. The cell using the LiFSA/SL electrolyte, which has the highest value of σ × t Li+, showed the best rate performance. Although the Li+ ion conductivity σ × t Li+ of [LiBF4]/[SL] = 1/2 is higher than that of [LiTFSA]/[SL] = 1/2, the rate capability of a Li–graphite cell with [LiTFSA]/[SL] = 1/2 electrolyte is better than one with [LiBF4]/[SL] = 1/2 . To investigate the interfacial resistance (R int) of graphite electrode/electrolyte, electrochemical impedance measurements were performed. Among the tested electrolytes, the [LiBF4]/[SL] = 1/2 electrolyte showed the highest R int probably due to the thick SEI layer on the graphite electrode. The higher R int might lead to the worse rate capability of the Li–graphite cell. Rate performances of Li–LiCoO2 cells with these electrolytes will also be reported. Acknowledgements This study was supported in part by JSPS KAKENHI (Grant Nos. 16H06368, 18H03926, and 19H05813) from the Japan Society for the Promotion of Science (JSPS) and the JST ALCA-SPRING Grant Number JPMJAL1301. References 1 Y. Yamada and A. Yamada, J. Electrochem. Soc., 2015, 162, A2406–A2423.2 K. Dokko, D. Watanabe, Y. Ugata, M. L. Thomas, S. Tsuzuki, W. Shinoda, K. Hashimoto, K. Ueno, Y. Umebayashi and M. Watanabe, J. Phys. Chem. B, 2018, 122, 10736–10745.3 A. Nakanishi, K. Ueno, D. Watanabe, Y. Ugata, Y. Matsumae, J. Liu, M. L. Thomas, K. Dokko and M. Watanabe, J. Phys. Chem. C, 2019, 123, 14229–14238.4 S. Kondou, M. L. Thomas, T. Mandai, K. Ueno, K. Dokko and M. Watanabe, Phys. Chem. Chem. Phys., 2019, 21, 5097–5105.5 Y. Ugata, M. L. Thomas, T. Mandai, K. Ueno, K. Dokko and M. Watanabe, Phys. Chem. Chem. Phys., 2019, 21, 9759–9768.6 S. Sasagawa, Y. Ugata, K. Ueno, K. Dokko, M. Watanabe, 236th ECS Meeting , Oct. 13-17, 2019, Atlanta, GA.

Effect of Anion Species on Ion Current Rectification Properties of Positively Charged Nanochannels.

Biological ion channels can realize delicate mass transport under complicated physiological conditions. Artificial nanochannels can achieve biomimetic ion current rectification (ICR), gating, and selectivity that are mostly performed in pure salt solutions. Synthetic nanochannels that can function under mixed ion systems are highly desirable, yet their performances are hard to be compared to those under pure systems. Seeking out the potential reasons by investigating the effect of mixed-system components on the ion-transport properties of the constructed nanochannels seems necessary and important. Herein, we report the effect of anions with different charges and sizes on the ICR properties of positively charged nanochannels. Among the investigated anions, the low-valent anions showed no impact on the ICR direction, while the high-valent component ferrocyanide [Fe(CN)64-] caused significant ICR inversion. The ICR inversion mechanism is evidenced to result from the adsorption of Fe(CN)64--induced surface charge reversal, which relates to solution concentration, pH conditions, and nanochannel sizes and applies to both aminated and quaternized nanochannels that are positively charged. Noticeably, Fe(CN)64- is found to interfere with the transport of protein molecules in the nanochannel. This work points out that the ion species from mixed systems would potentially impact the intrinsic ICR properties of the nanochannels. Replacing highly charged counterions with organic components would be promising in building up future nanochannel-based mass transport systems running under mixed systems.

Effect of Anion Species in Early Stage of SEI Formation Process

We investigate the early stage of the solid electrolyte interphase (SEI) layer formation process in four electrolyte solutions, using electrochemical quartz crystal microbalance (EQCM) and X-ray photoelectron spectroscopy (XPS). The EQCM result proves that the LiBH4 in THF solution form a negligible amount of SEI layer. The SEI formation process of the LiPF6 solution occurs at 2.3 V vs. Li, and the SEI layer continuously grows even during the anodic scan. The electrolyte solutions containing LiTFSA form SEI layer around 1.5 V vs. Li. The XPS study shows that the SEI layer formed at high electrode potential, in the electrolyte containing LiPF6 forms a dense LiF layer. The LiTFSA solution forms a thick SEI layer containing organic components such as lithium alkyl carbonate or polyether.

Mechanistic study on metal-free acetylene hydrochlorination catalyzed by imidazolium-based ionic liquids

A novel green approach to acetylene hydrochlorination yielding vinyl chloride is presented using 1-alkyl-3-methyimidazolium-based ionic liquids (ILs) as single component metal-free catalysts. The effects of anion species and substituent group in the imidazolium cation on the reaction are investigated. Through the catalytic performance and computational simulation, the catalytic mechanism of single component ILs for metal-free acetylene hydrochlorination is proposed. It is suggested that ILs as single component metal-free catalysts must consist of chloride anion, which is participate in the reaction process of acetylene hydrochlorination to form [HCl2]− through the activation of HCl molecule. Notably, the structural modification of conjugated cation will be the key factor to further improve the catalytic efficiency. The mechanistic understanding has an important significance to modify the metal-free catalytic efficiency of ILs for acetylene hydrochlorination.

Electrochemical Reduction of CO2 in Water‐Based Electrolytes KHCO3 and K2SO4 Using Boron Doped Diamond Electrodes

AbstractThe performance of Boron Doped Diamond (BDD) electrodes for the electrochemical reduction of CO2 at room temperature and in water‐based electrolytes was investigated. Techniques such as linear sweep voltammetry, chronoamperometry, and chronopotentiometry were used to confirm the activity of BDD for the CO2 reduction. Besides H2, CO and HCOOH were found as major products with CH3OH as a minor product. The effect of anionic species with and without buffer capacity was investigated using KHCO3 and K2SO4 as electrolytes. BDD did not show any degradation after using it in several experiments. The Faradaic efficiency (FE) for CO in the gas phase and the concentration of HCOOH in the liquid phase were higher in K2SO4 than in KHCO3. However, the total FE for C1 products was lower than 20%. Then BDD electrodes were modified with silver, which improved the FE for CO to 68% in K2SO4 at −1.8 V vs. Ag/AgCl. Galvanostatic experiments were also performed for 10 hours at −10 mA cm−2 producing 30% FE for CO in the gas phase and 43,9 mM HCOOH in the liquid phase.

Selective separation of H2S and CO2 from CH4 by supported ionic liquid membranes

Supported ionic liquid membranes (SILMs) are considered as promising media for the upgrading of natural gas. However, most research has focused on the selective separation of CO2 and CH4, paying little attention to the selective separation of H2S and CH4 or H2S and CO2 in SILMs. In this work, the permeability of CH4, CO2, and H2S in two different categories of ionic liquids (neutral and basic ionic liquids) were systemically investigated under dry conditions. The ideal selectivity of CO2/CH4, H2S/CH4, and H2S/CO2 were calculated. The effect of anion species, transmembrane pressure difference, and temperature on the permeability of single gas and ideal selectivity of gas pairs were studied. It is found that neutral ionic liquids (1-butyl-3-methylimidazolium tetrafluoroborate and 1-butyl-3-methylimidazolium trifluoromethanesulfonate) show high permeability of CO2 and H2S, and competitive permselectivity of CO2/CH4 and H2S/CH4, and thus can be used for the simultaneous removal of H2S and CO2 from natural gas. Basic ionic liquids (1-butyl-3-methylimidazolium acetate) show not only high permeability of CO2 and H2S, but also superior permselectivity of CO2/CH4, H2S/CH4 and H2S/CO2, and thus can be potentially used for selective removal of H2S from natural gas. Moreover, facilitated transport of H2S and CO2 were observed in 1-butyl-3-methylimidazolium acetate. To the best of our knowledge, this is the first time that the facilitated transport of H2S in SILMs is reported.

Femtosecond Raman-Induced Kerr Effect Study of Temperature-Dependent Intermolecular Dynamics in Imidazolium-Based Ionic Liquids: Effects of Anion Species and Cation Alkyl Groups.

The temperature dependence of the intermolecular vibrational dynamics in imidazolium-based ionic liquids (ILs) with 10 different anions was studied by femtosecond Raman-induced Kerr effect spectroscopy. For all ILs investigated in this study, the intensity in the low-frequency region below 50 cm-1 increases, and the spectral density in the high-frequency region above 80 cm-1 decreases (and shows a redshift) with increasing temperature. The first phenomenon would be attributed to the activation of the translational vibrational motions, whereas the second one is ascribed to the slowing librational motion of the imidazolium ring with increasing temperature. Calculated spectra of the density of states for the intermolecular vibrations of 1-butyl-3-methylimidazolium hexafluorophosphate, which is one of the experiment samples studied here, obtained by molecular dynamics simulation agreed well with the experimental results and confirmed the spectral assignments. When we compared the difference spectra between spectra measured at various temperatures and the spectrum measured at 293 K, a clear difference was found in the ∼50 cm-1 region of the Kerr spectra of 1-butyl-3-methylimidazolium thiocyanate and 1-butyl-3-methylimidazolium dicyanamide from those of the other ILs. The difference might have originated from the librational motions of the corresponding anions. We also compared the temperature-dependent Kerr spectra of hexafluorophosphate salts of 1-butyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium, and 1-heptyl-3-methylimidazolium cations. These ILs showed a similar temperature dependence, which was not affected by the alkyl group length. The temperature-dependent viscosities and glass transition temperatures of the ILs were also estimated to determine their fragilities.

Fabrication of Zinc Oxide Semiconductor Nanoparticles in the Apoferritin Cavity

We developed a liquid phase ZnO nanoparticles (NPs) fabrication method which employed the cage-shaped protein apoferritin as a biotemplate. The suppression of the chemical reaction outside apoferritin by stabilizing Zn2+ with ammonia allowed the selective NP synthesis inside the cavity at room temperature. The composition of synthesized NPs was confirmed to be that of ZnO, and their size was determined to be 5.1 ± 0.8 nm in diameter through energy-dispersive X-ray spectroscopy and high-resolution transmission electron microscopy. In-depth studies about the effect of anion species on the NP formation proved that the anion introduction through the channels was competitive and also that the decrease in hydroxide ion (OH–) concentration ratio in the reaction solution led to less ZnO NPs formation.

Synergistic extraction of zinc from ammoniacal solutions using β-diketone mixed with CYANEX923 or LIX84I

Abstracts The extraction behaviors of zinc from ammoniacal solutions were investigated using β-diketone (HA) and their mixtures with CYANEX923 or LIX84I. The effects of pH, total ammonia concentration, extractant concentration, anion species and temperature on zinc extraction were examined. The synergistic mechanism was discussed with regard to the structure of extractant and the extracted zinc complexes. It is found that the increase of total ammonia concentration and pH inhibits zinc extraction for all extraction systems due to the formation of zinc ammine complexes in aqueous phase. This effect of HA with CYANEX923 is evidently smaller than that of HA with LIX84I or HA alone system. Effect of anion species on the zinc extraction by HA with CYANEX923 can be neglected, but this effect of HA alone and the mixture of HA with LIX84I decreases in the order of (NH 4 ) 2 SO 4 > NH 4 NO 3 > NH 4 Cl.

Effects of Anionic Species on the Polarization Behavior of Copper for Waste Package Material in Artificial Ground Water

Effects of Anionic Species on the Polarization Behavior of Copper for Waste Package Material in Artificial Ground Water

Morphological dependency of polymer electrolyte membranes on transient salt type: effects of anion species

AbstractTwo types of transition metal salts, i.e. Cu(NO3)2 and CuCl2, with different anion species were used to prepare various polyethersulfone‐based poly(N‐vinyl pyrrolidone) (PVP) composite membranes. The polymer crystallinity, strength of some of the bonds in the membrane structure and effects of anion species on the membrane morphology were investigated through X‐ray diffraction (XRD), scanning electron microscopy with energy‐dispersive X‐ray spectrometry (SEM‐EDX), Fourier transform infrared (FTIR) spectroscopy and atomic force microscopy. The XRD results indicated an enhancement of the PVP crystallinity after addition of Cu(NO3)2. Moreover, addition of copper salt was accompanied by an increase of effective membrane distances. The FTIR analysis revealed that the nitrate ions might be better distributed than the other salt ions. The complexes created between them and carbonyl oxygens on the PVP chains were thus stronger. More powerful interactions caused a crystallinity enhancement following the addition of Cu(NO3)2. The SEM‐EDX experiment gave insight into the copper ion and carbonyl oxygen distributions in the membrane surface and active layer. The uniform distribution of copper ions resulted in a clear distribution of interchain interactions and complexes in the active layer structure and also caused structural order improvement. Copyright © 2010 Society of Chemical Industry

Effect of anion species on infinite dilution activity coefficients of epoxides in imidazolium-based ionic liquids

The infinite dilution activity coefficients of 1,2-epoxypropane, 1,2-epoxybutane, 2-methyl-1,2-epoxypropane and 1,2-epoxyhexane in the ionic liquids with 1-butyl-3-methylimidazolium cation ([bmim]), [bmim][BF 4] and [bmim][PF 6] were measured by gas–liquid chromatograph (GC) from (325.2–363.4) K and atmospheric pressure. The ionic liquids were used as stationary phases in GC. The experimental data of the activity coefficients were determined from the extrapolations to zero of the gas flow rate on GC. The activity coefficients of the all epoxides in [bmim][PF 6] are smaller than those in [bmim][BF 4]. The partial molar excess enthalpies and entropies at infinite dilution for the epoxides in the ionic liquids were obtained from the experimental data of the activity coefficients. The enthalpies for the epoxides in [bmim][PF 6] are negative. The values of entropies in [bmim][PF 6] are lower than those in [bmim][BF 4]. It can be explained that the interactions of the epoxides with [bmim][PF 6] are larger than those with [bmim][BF 4].

Effects of anion species and concentration on the removal of Cr(VI) by a microalgal isolate, Chlorella miniata

The presence of nitrate, chloride and sulfate anions on the removal of Cr(VI) by Chlorella miniata was investigated. Results of kinetic studies indicated that the equilibrium time in each anion system increased with increases of the initial salt concentration, and the inhibitory order was NO 3 − > Cl − > SO 4 2− for Cr(VI) removal and was SO 4 2− > Cl − ≈ NO 3 − for the biosorption of the bioreduced Cr(III). The inhibitory effect caused by different anions was attributed to biosorption mechanism and metal speciation. Since both biosorption and bioreduction were involved in Cr(VI) removal, the presence of anions could compete with Cr(VI) for the adsorption sites, and the affinity of anions to the algal biomass followed the order of NO 3 − > Cl − > SO 4 2−, which was consistent with their inhibitory order on Cr(VI) removal. Speciation results also indicated that the formation of CrO 3SO 4 2− in the sulfate system made it easier to be adsorbed on the biomass than HCrO 4 −. The biosorption–bioreduction model further suggested that the bioreduction rate constant k decreased with increases of anion concentrations ranging from 0 to 0.5 M, and followed the order of SO 4 2− > Cl − > NO 3 −. The biosorption constant b also decreased with anion concentrations in the range of 0–0.2 M, suggesting that this parameter was more sensitive to anion effects than the k values. The higher b values in the sulfate than in the nitrate and chloride systems indicated that Cr(VI) in the sulfate system was more easily adsorbed on the algal biomass. These findings demonstrated that the presence of anions significantly affected the removal of Cr(VI) by C. miniata. Since chloride, nitrate and sulfate ions are commonly found in industrial wastewater, it may be necessary to eliminate these ions prior to chromium removal.

Effect of anion species from Ca-sources on framework type of Na–Ca zeolites prepared at 80°C

Na–Ca zeolites were synthesized at 80°C from the mixtures of sodium orthosilicate as a Si-source, Al(OH)3 powder as a Al-source, and Ca-sources. A variety of calcium salts highly soluble in␣water were chosen in this work: CaCl2, CaI2, Ca(HCOO)2, Ca(CH3COO)2, and Ca(EtCOO)2 to investigate the effect of anion species from the Ca-sources on the framework type and crystallinity of Na–Ca zeolites. The crystal phase diagrams as functions of the molar ratio SiO2/Al2O3 and reaction period were determined for different Ca-source systems on the basis of the XRD patterns and SEM observations. The use of CaCl2 or CaI2 as a Ca-source led to faujasite, hydroxysodalite, and gismondine, whereas hydroxycancrinite was preferentially produced from the reactants including Ca(NO3)2 independent of SiO2/Al2O3 (=4–20) and reaction period (168–840 h). It was found that the presence of iodine anion strongly hinders the crystallization of Na–Ca zeolites, in particular, in a high SiO2/Al2O3 range. On the other hand, the systems containing organic carboxylates gave more complex results where faujasite, hauyne, gismondine, and hydroxycancrinite were formed. All the reaction systems containing these anion species, as well as NO3-, also underwent the dissolution–nucleation–growth processes after faujasite was yielded at the early stage, as a result, the zeolite framework type varied from faujasite to hydroxysodalite, hauyne, and finally gismondine or hydroxycancrinite.

Effects of Anion Species on Deintercalation of Carbonate Ions from Hydrotalcite-like Compounds

Abstract The deintercalation of carbonate ions from a hydrotalcite-like compound (MgAl-LDH) was investigated using salt-HCl mixed solutions with sodium salts containing various monovalent anion species. The deintercalation was influenced by the anion species, and the carbonate ions were deintercalated most easily for the system containing Cl− or Br− anions.

均一沈殿法によるＹ２Ｏ３：Ｅｕ微粒子合成における陰イオン種の影響

The effect of anionic species (SO4 2-, Cl-, NO3-) in synthesizing fine particles of phosphor (Y2O3 : Eu) from the homogeneous solution which dissolved Y2O3 and Eu2O3 by the addition of H2SO4, HCl or HNO3 by liquid-phase method which used the urea for the precipitant generator was studied. The shape of synthetic fine particles is different by the anionic species in the solution, and in the system including SO42-, the shape of the fine particles was irregular, and in the system including Cl- or NO3-, it was spherical and monodispersed. Monodispersed spherical fine particles synthesized from the solution including Cl- or NO3- was guessed with the amorphous basic carbonate. On the other hand, the fine particle synthesized from the solution including SO42- showed crystal structure, and it was the different composition which contained the SO42- as a component. The fine particles synthesized from the solution including Cl- or NO3 - were inverted to the monophase of metal oxide by calcination at the temperature ove r about 600°C, and it confirmed that it was not almost influenced to spherical form and monodispersion. And, these calcined fine particles showed fluorescence spectra with luminescence peak in 611nm which was peculiar to the Y2O3 : Eu phosphor. On the other hand, in case of the synthesis from the solution including SO4 2-, SO42- contained in the fine particle remained after calcination, and the crystallinity after calcination was comparatively low. And, these calcined fine particles showed different fluorescence spectra with the Y2O 3 : Eu phosphor.

Effects of Anionic Species on the Polarization Behavior of Copper for Waste Package Material in Artificial Ground Water

AbstractThe effects of HCO3, Cl, and SO42- on copper as a candidate material for overpacking for geological disposal of high level radioactive wastes are studied at 303 K in dissolved oxygen(DO)- controlled, ground-water simulating aqueous solutions by using a cyclic polarization curve method.Two types of polarization curve were determined: Type A in which free corrosion proceeds in the active dissolution mode, and Type P in which passivation takes place in a potential domain characterized by a potential that corresponds to Eb, the potential at which the passivated film is broken. Polarization dependence on DO was also determined: when only HCO3 is present, a Type A curve results for DO < 0.5 ppm when HCO3 = 10 – 300 ppm, transiting to a Type P curve when HCO3 > 3,000 ppm; when DO < 15ppm, however, a Type P results for HCO3 ≤ 10 ppm; when either Cl− or SO42- coexists with HCO3, HCO3 promotes passivation while Cl- and SO42- promote active dissolution, the influence of Cl− being greater than that of HO42- if HCO3 content is constant. The presence of either CI or SO42 over 100 ppm makes the curve Type A irrespective of DO, both species shifting Eb toward the less noble direction.The constant potential test shows that the passivated film of copper is easily broken if Cl− is present.