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The continual increase in energy demand and inconsistent supply have attracted attention towards sustainable energy storage/conversion devices, such as electrochemical capacitors with high energy densities and power densities. Perovskite oxides have received significant attention as anion-intercalation electrode materials for electrochemical capacitors. In this study, hollow nanospheres of non-stoichiometric cubic perovskite fluorides, KNi1−xCoxF3−δ (x = 0.2; δ = 0.33) (KNCF-0.2) have been synthesized using a localized Ostwald ripening. The electrochemical performance of the non-stoichiometric perovskite has been studied in an aqueous 3 M KOH electrolyte to categorically investigate the fluorine-vacancy-mediated charge storage capabilities. High capacities up to 198.55 mA h g−1 or 714.8 C g−1 (equivalent to 1435 F g−1) have been obtained through oxygen anion-intercalation mechanism (peroxide pathway, O - ). The results have been validated using ICP (inductively coupled plasma mass spectrometry) analysis and cyclic voltammetry. An asymmetric supercapacitor device has been fabricated by coupling KNCF-0.2 with activated carbon to deliver a high energy density of 40 W h kg−1 as well as excellent cycling stability of 98% for 10,000 cycles. The special attributes of hollow-spherical, non-stoichiometric perovskite (KNCF-0.2) have exhibited immense promise for their usability as anion-intercalation type electrodes in supercapacitors.

International audience; The symmetry or structural stability of ABO(3)-type perovskite oxides depends largely on the size of 'A' and 'B' cations, which determines the material properties. The partial substitution of these cations may be used to tune these properties. The ionic sizes and valence states of the cations play an important role in improving the properties of perovskite. In this study, the substitution of La3+ with Sr2+ with a larger ionic radius and Mn3 + with Fe(3+& nbsp;)with a similar ionic radius favored both the crystal symmetry and the mixed ionic-electronic conductivity of the perovskite. Electrodes based on La0.7Sr0.3Mn0.5Fe0.5O3 (LSMFO55) exhibited a faradaic behavior with a specific capacity of 330 C g(-1) (92 mAh g(-1)) at 12C rate, while this electrode maintained a capacity of 259 C g(-1) at 240C (charge or discharge in 15 s). Additionally, exohedral carbon nano-onions (CNO) were introduced as a negative electrode to design an asymmetric hybrid supercapacitor (AHS) with a widened cell voltage. The use of CNO as a negative electrode in the AHS improved the rate capability drastically compared to the use of rGO. This device maintained a good energy density even at an extra-high charging rate (600C) owing to its outstanding rate capability. The high-rate performance of the LSMFO55//CNO AHS can be elucidated by successful fabrication with a mixed ionic-electronic conductive positive electrode and a CNO negative electrode. Tuning the electronic and ionic conductivities by cationic substitution and adopting an appropriate carbon-derived negative electrode (such as CNO) can provide a practical high-rate hybrid device using various perovskites.

Zinc ferrite and graphene composites have attracted considerable attention in wastewater treatment. In this work, a magnetically separable mesoporous composite of ZnFe2O4 nanoparticles (NPs) and reduced graphene oxide (rGO) was prepared through a simple and eco-friendly method with pure water as solvent and without the need for subsequent thermal treatment. Uniformly dispersed ZnFe2O4 NPs on the surface of rGO sheets exhibited good crystallinity and a large BET specific surface area. These factors contributed to good photocatalytic performance of the composite for the degradation of methylene blue (MB) under simulated solar-light radiation, increased adsorptivity, increased separation efficiency of the photo-excited charges on the surface of the catalyst, and broadened light-absorption range of the composite. Efficient interfacial interaction between the ZnFe2O4 NPs and rGO sheets resulted in synergistic effects. The magnetically separable ZnFe2O4@rGO nanocomposite proved an efficient and stable catalyst in three consecutive photodegradation cycles for MB dye in aqueous solution under solar radiation. In addition, the synthesis method proposed in this study could be scaled-up easily due to the simplicity of the process, the lack of a toxic reagent, and the use of low temperatures.

Metal oxide/graphene photocatalysts have been attracting considerable attention in solving environmental pollution problems because of the limitations of the semiconductor-based photocatalysts. In this study, highly efficient and inexpensive zinc oxide (ZnO) nanoparticles with three different morphologies, such as nanospheres, nanodisks, and nanorods, anchored on reduced graphene oxide (RGO) were synthesized in solvent mixtures with different ethanol to water ratios. Among the three morphologies, the nanospherical ZnO/RGO (sZG) composite exhibited the highest methylene blue (MB) and rhodamine B removal efficiencies at 99% and 98%, respectively, after only 60 min under low-power (40 W) ultraviolet irradiation at a low catalyst loading of 0.1 g L−1. This nanocomposite also showed excellent photocatalytic stability under UV irradiation, retaining 96% efficiency even after 15 cycles of MB degradation. Moreover, the sZG composite exhibited a high MB degradation efficiency of approximately 99% after 100 min at a low catalyst loading of 0.2 g L−1 under solar light illumination. The excellent photocatalytic performance and high stability of this low-cost nanospherical ZnO/RGO composite exemplarily highlights the potential of sustainable next-generation photocatalysis for treating wastewater containing organic pollutants.

Three-dimensional (3D) γ-MnO2@ZnFe2O4/reduced graphene oxide (rGO) nanohybrids were synthesized using a one-pot hydrothermal self-assembly method. The morphology and properties of the nanohybrids were investigated. The synergistic interactions among γ-MnO2, ZnFe2O4, and rGO resulted in 3D nanoflakes distributed uniformly in the rGO structure with a thickness of approximately 2–5 nm, leading to a high surface area. The nanohybrid containing 10 wt. % rGO exhibited superior catalytic activities for phenol degradation through the activation of peroxymonosulfate (PMS) to generate active sulfate radicals ( S O 4 • – ). Typically, 50 mL of a 20 ppm phenol solution was degraded completely and 85% of the carbon content had been mineralized in 30 min at 25 °C using 10 mg of the nanohybrid. The nanohybrid could be recovered easily using a magnet and reused, maintaining high stability during catalytic oxidation. The 3D γ-MnO2@ZnFe2O4/rGO nanohybrid catalyst could be applied to the removal of hard-to-degrade waste materials owing to its high efficiency and excellent reusability.

The GERG-2008 equation of state is the approved ISO standard (ISO 20765-2) for the calculation of thermophysical properties of natural gas mixtures. The composition of natural gas can vary considerably due to the diversity of origin. Further diversification was generated by adding hydrogen, biogas, or other non-conventional energy gases. In this work, high-precision experimental (p, ρ, T) data for two gravimetrically prepared synthetic natural gas mixtures are reported. One mixture resembled a conventional natural gas of 11 components (11 M) with a nominal mixture composition (amount-of-substance fraction) of 0.8845 for methane as the matrix compound with the other compounds being 0.005 for oxygen, 0.04 for nitrogen, 0.015 for carbon dioxide, 0.04 for ethane, 0.01 for propane, 0.002 each for n- and isobutane, and ultimately 0.0005 each for isopentane, n-pentane, and n-hexane. The other mixture was a 13-component hydrogen-enriched natural gas with a low calorific value featuring a nominal composition of 0.7885 for methane, 0.03 for hydrogen, 0.005 for helium, 0.12 for nitrogen, 0.04 for carbon dioxide, 0.0075 for ethane, 0.003 for propane, 0.002 each for n- and isobutane, and 0.0005 each for neopentane, isopentane, n-pentane, and n-hexane. Density measurements were performed in an isothermal operational mode at temperatures between 260 and 350 K and at pressures up to 20 MPa by using a single-sinker densimeter with magnetic suspension coupling. The data were compared with the corresponding densities calculated from both GERG-2008 and AGA8-DC92 equations of state to test their performance on real mixtures. The average absolute deviation from GERG-2008 (AGA8-DC92) is 0.027% (0.078%) for 11 M and 0.095% (0.062%) for the 13-component H2-enriched mixture, respectively. The corresponding maximum relative deviation from GERG-2008 (AGA8-DC92) amounts to 0.095% (0.127%) for 11 M and 0.291% (0.193%) for the H2-enriched mixture.

Producción Científica, Continuing our study on (CO2 + O2) mixtures, this work reports new experimental (p, ρ, T) data for two oxygen-rich mixtures with mole fractions x(O2) = (0.50 and 0.75) mol·mol−1, in the temperature range T = (250 to 375) K and pressure range p = (0.5 to 20) MPa, using a single-sinker densimeter. Experimental density data were compared to two well established equation-of-state models: EOS-CG and GERG-2008. In the p, T-range investigated, the EOS-CG gave a better reproduction for the equimolar mixture (x(O2) = 0.5), whereas the GERG-2008 performed significantly better for the oxygen-rich mixture (x(O2) = 0.75). The EOS-CG generally overestimates the density, while the GERG-2008 underestimates it. This complete set of new experimental data, together with previous measurements, is used to calculate the virial coefficients B(T, x) and C(T, x), as well as the second interaction virial coefficient B12(T) for the (CO2 + O2) system., Ministerio de Economía, Industria y Competitividad project ENE2017-88474-R, Junta de Castilla y León project VA280P18

Twenty years ago, research involving ionic liquids was a minor field of interest, and only a few chemists and even fewer engineers were interested in salts with melting points near room temperature. In April 2000, the first NATO advanced research workshop on ionic liquids was held in Heraklion, Crete. The conference was the first international meeting devoted to ionic liquids and attracted most of the active researchers at that time. Following that meeting, activity in the field began to flourish and the first books and international conferences devoted to ionic liquids began to appear. By the end of 2018, more than 80,000 scientific papers had been published, and 17,000 patents were applied for in the field of ionic liquids! This book provides an overview of the current and emerging industrial applications of ionic liquids covering the core processes and products, the practical implementation and technical challenges involved, and the potential future directions for research and development. The individual chapters were written by leading scientists in the field from industry and academia to address specific processes and products that are or will be soon commercialized. Examples include the use of a chloroaluminate ionic liquid as a next-generation alkylation catalyst to a new class of capillary gas chromatography (GC) columns with stationary phases based on ionic liquids. Over the past twenty years, there has been a growing realization that ionic liquids have moved from being mere academic curiosities to having genuine applications in fields as wide-ranging as advanced materials, biotechnology, catalysis, pharmaceuticals, renewable fuels, and sustainable energy. There are many optimistic indications that ionic liquids are on their way to becoming a commercial success story. This first book on “Commercial Applications of Ionic Liquids” provides over 50 applications that are either at the pilot scale or have been commercialized, which indicates that an exciting new chapter in the field of ionic liquids is about to begin!

Producción Científica, The limited availability of accurate experimental data in wide ranges of pressure, temperature, and composition is the main constraining factor for the proper development and assessment of thermodynamic models and equations of state. In the particular case of carbon capture and storage (CCS) processes, there is a clear need for data sets related to the (carbon dioxide + oxygen) mixtures that this work aims to address. This work provides new experimental (p, ρ, T) data for three binary (CO2 + O2) mixtures with mole fractions of oxygen x(O2) = (0.05, 0.10, and 0.20) mol·mol-1, in the temperature range T = (250 to 375) K and pressure range p = (0.5 to 13) MPa. The measurements were performed with a high-precision single-sinker densimeter with magnetic suspension coupling. The density data were obtained with estimated expanded relative uncertainties of 0.02 % for the highest densities, and up to 0.3 % for the lowest ones.The results were compared to the corresponding results calculated by the current reference equations of state for this kind of mixtures, namely the EOS-CG (combustion gases) and the GERG-2008 equation of state, respectively. The EOS-CG yields better estimations in density than the GERG-2008 equation of state. The results from the EOS-GC model show no systematic temperature dependence. For the GERG-2008 model, however, this criterion is significantly less fulfilled., Ministerio de Economía, Industria y Competitividad project ENE2017-88474-R, Junta de Castilla y León project VA280P18

Producción Científica, Speed of sound is one of the thermodynamic properties that can be measured with least uncertainty and is of great interest in developing equations of state. Moreover, accurate models are needed by the H2 industry to design the transport and storage stages of hydrogen blends in the natural gas network. This research aims to provide accurate data for (CH4 + H2) mixtures of nominal (5, 10, and 50) mol-% of hydrogen, in the p = (0.5 up to 20) MPa pressure range and with temperatures T = (273.16, 300, 325, 350, and 375) K. Using an acoustic spherical resonator, speed of sound was determined with an overall relative expanded (k = 2) uncertainty of 220 parts in 106 (0.022 %). Data were compared to reference equations of state for natural gas-like mixtures, such as AGA8-DC92 and GERG-2008. Average absolute deviations below 0.095% and percentage deviations between 0.029% and up to 0.30%, respectively, were obtained. Additionally, results were fitted to the acoustic virial equation of state and adiabatic coefficients, molar isochoric heat capacities and molar isobaric heat capacities as perfect-gas, together with second and third acoustic virial coefficients, and were estimated. Density second virial coefficients were also obtained., Ministerio de Economía, Industria y Competitividad project ENE2017-88474-R, Junta de Castilla y León VA280P18

Main text CCQM-K118 was an international key comparison on natural gas composition with two types of gases, i.e., a low calorific hydrogen-enriched natural gas and a high calorific LNG type of gas. There were 14 participating laboratories. The traveling standards (i.e., 14 mixtures each) were obtained from an external source and checked for homogeneity and stability before and after the participants' measurements at the two coordinating laboratories. The data evaluation was performed using a consensus value and a laboratory effect model. The results of the participants were benchmarked against a key comparison reference value computed from the largest consistent subset (LCS) of the submitted results, adjusted for the differences between the travelling standards. For the first time in a key comparison in gas analysis, the model included a term to account for excess variability in the LCS. Most of the participants reported one or a few (slightly) discrepant results. Partly this is due to the heterogeneity and heteroscedasticity of the datasets. In all, the results in this key comparison demonstrate the good comparability of the national measurement standards for natural gas composition maintained by the participating NMIs. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA). To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

The paramagnetic ionic liquid 1-butyl-3-methylimidazolium tetrachloroferrate [BMIM][FeCl4] was subject to multiple high-precision thermophysical property measurements under both ambient and high pressure. Density ρ(p0,T) / kg·m−3 and speed of sound u(p0,T) / m·s−1 data at ambient pressure were recorded at temperatures T = (278.15 to 343.16) K using a DSA 5000 M combined vibrating tube densimeter and speed of sound analyser with a standard uncertainty of Δρ(p0,T) = ±0.001 kg·m−3 and Δu(p0,T) = ±0.1 m·s−1, respectively. High-pressure volumetric (p,ρ,T) data were measured on an Anton Paar DMA HPM vibrating tube densimeter at T = (273.16 to 413.15) K and at pressures up to p = 140 MPa with an estimated experimental relative combined average percentage deviation (APD) of Δρ(p,T) / ρ(p,T) = ±(0.01 to 0.08) %. The specific isobaric heat capacity cp(p0,T) / J·kg−1·K−1, a caloric property, was determined at T = (273.15 to 413.15) K with an uncertainty Δcp / cp = ±0.5 % using a Perkin Elmer Pyris 1 DSC differential scanning calorimeter. To gain knowledge of transport properties, the dynamic viscosity η(p0,T) / mPa·s at ambient pressure was recorded at T = (275.03 to 413.18) K by an Anton Paar SVM 3000 Stabinger viscometer and additionally an Anton Paar rheometer MCR 302 device with uncertainties of Δη / η = ±0.35 % and Δη / η = ±1 %, respectively. The obtained data were first correlated by empirical polynomial equations of state and further processed by the application of classic thermodynamic potentials to determine isothermal compressibility κT(p,T) / MPa−1, isobaric thermal expansivity αp(p,T) / K−1, thermal pressure coefficient γ(p,T) / MPa⋅K−1, internal pressure pint(p,T) / MPa, specific heat capacity at constant pressure cp(p,T) / J⋅kg−1⋅K−1 and at constant volume cv(p,T) / J⋅kg−1⋅K−1, the difference of isobaric and isochoric heat capacity (cp–cv)(p,T) / J⋅kg−1⋅K−1, speed of sound u(p,T) / m⋅s−1 and ultimately isentropic exponent κs(p,T). This work extends knowledge about the thermophysical properties of [BMIM][FeCl4] particularly to high temperatures and pressures.

Present study investigated decoration of Cu(OH)2 with different morphologies by copper precursors, on 3D nickel foam. The Cu(OH)2-A (nano flower)electrode showed an excellent capacitance of 1332 F g−1 at current density of 2 A g−1 compared to the Cu(OH)2-C (nano ribbon, 1100 F g−1) and Cu(OH)2-S (nano long leaf, 1013 F g−1) electrodes. Asymmetric supercapacitor (ASC) was fabricated, and showed maximum capacitance of 165 F g−1 at current density of 2 A g−1with high energy density of 66.7 Wh kg−1 and power density of 5698 W kg−1 with excellent stability of 80% after 10,000 cycles.

In Memoriam Professor Dr. rer. nat. Gerhard Manfred Schneider (May 7, 1932 – October 16, 2020) Professor and Chair of Physical Chemistry, Ruhr-University, Bochum, Germany (1969-1997)

Solubility data of carbon dioxide (CO2) in the ionic liquid 1-ethyl-3-methylimidazolium methanesulfonate [EMIM][CH3SO3] at T = (273.15 to 413.15) K and pressures up to p = 5.0 MPa are reported. The solubility measurements were carried out using an isochoric method which operates in decrements of ΔT = 20 K within the investigated temperature range and at selected four different pressure steps ranging from a pressure p of around 5.0 MPa down to around 0.4 MPa. The solubility of CO2 in the ionic liquid monotonously decreases with increasing temperatures at a constant pressure. Within the p,T-range investigated, CO2 displayed a solubility in [EMIM][CH3SO3] from a mole fraction x = 0.0160 mol·mol−1 and a corresponding molality m = 0.0791 mol·kg−1 at T = 413.15 K and p = 0.432 MPa up to x = 0.4049 mol·mol−1 and m = 3.2982 mol·kg−1 at T = 293.15 K and p = 4.577 MPa. Henry's law constant was calculated from the solubility data reported here, and literature data were reviewed for comparison. Additionally, thermodynamic state properties that can be derived from Henry's law constant, such as the Gibbs energy of solvation ΔsolG, the enthalpy of solvation ΔsolH, the entropy of solvation ΔsolS, and the heat capacity of solvation ΔsolCp, were calculated.

This work aims to address the technical aspects related to the thermodynamic characterization of natural gas mixtures blended with hydrogen for the introduction of alternative energy sources within the Power-to-Gas framework. For that purpose, new experimental speed of sound data are presented in the pressure range between (0.1 up to 13) MPa and at temperatures of (260, 273.16, 300, 325, and 350) K for two mixtures qualified as primary calibration standards: a 11 component synthetic natural gas mixture (11 M), and another low-calorific H2-enriched natural gas mixture with a nominal molar percentage x H 2 = 3 % . Measurements have been gathered using a spherical acoustic resonator with an experimental expanded (k = 2) uncertainty better than 200 parts in 106 (0.02%) in the speed of sound. The heat capacity ratio as perfect-gas γpg, the molar heat capacity as perfect-gas Cp,mpg, and the second βa and third γa acoustic virial coefficients are derived from the speed of sound values. All the results are compared with the reference mixture models for natural gas-like mixtures, the AGA8-DC92 EoS and the GERG-2008 EoS, with special attention to the impact of hydrogen on those properties. Data are found to be mostly consistent within the model uncertainty in the 11 M synthetic mixture as expected, but for the hydrogen-enriched mixture in the limit of the model uncertainty at the highest measuring pressures.

The experimental density data of the binary system nitrogen-hydrogen available at the time of the development of the equation of state for natural gases and related mixtures, GERG-2008, were limited to hydrogen contents higher than 0.15 (amount-of-substance fraction) and temperatures above 270 K. This work provides accurate experimental (p, ρ, T) data for three binary mixtures of nitrogen and hydrogen: (0.95 N2 + 0.05 H2), (0.90 N2 + 0.10 H2), and (0.50 N2 + 0.50 H2) at temperatures of (240, 250, 260, 275, 300, 325, and 350) K, thus extending the range of available experimental data to low hydrogen contents and low temperatures. The density measurements were performed by using a single-sinker densimeter with magnetic suspension coupling at pressures up to 20 MPa. Experimental data were compared with the corresponding densities calculated from the GERG-2008 and the AGA8-DC92 equations of state. The relative deviations of the experimental data from both equations of state were within the estimated uncertainty value of the equations. Therefore, the experimental data agree very well with the values estimated from the equations. The virial coefficients B(T,x), C(T,x), and D(T,x) as well as the second interaction virial coefficient for the nitrogen-hydrogen binary system were also calculated from the experimental data set at temperatures from (240 to 350) K. The resulting values agree with those from literature., 2018-11-03, MEC ENE2013-47812-R, European Commission’s ENG54, Junta de Castilla y León VA035U16

Nanocomposites of Ag-ZnFe 2 O 4 @reduced graphene oxide (rGO) were synthesized using a one-pot microwave-assisted self-assembly method. The morphology and structure of the Ag-ZnFe 2 O 4 @rGO nanocomposites were characterized. The nanocomposites formed with 15.2 wt% rGO showed excellent adsorption properties and high photocatalytic activity for the degradation of methylene blue (MB), rhodamine B (RhB), and methyl orange (MO). The synergistic interactions between Ag, ZnFe 2 O 4 , and rGO decreased the aggregation of the nanoparticles (NPs) and increased the surface area, resulting in better absorption in both UV and visible light. Such a structure was helpful for separating the photo-excited electron-hole pairs and accelerating electron transfer. Electrochemical impedance spectroscopy (EIS) revealed a smaller resistance in the solid-state interface layer and charge transfer on the composite surface than that of the bare ZnFe 2 O 4 NPs and ZnFe 2 O 4 @rGO nanocomposite. The Ag-ZnFe 2 O 4 @rGO nanocomposite could be recovered easily by a magnet and reused five times with no significant decrease in photocatalytic activity. The as-prepared Ag-ZnFe 2 O 4 @rGO nanocomposite catalyst could be applied to the removal of hard-to-degrade waste materials owing to its high efficiency in both UV and visible light and its excellent reusability.

With the vast exploration of the applications of graphene, researchers are assessing different methods for fabricating graphene-based electrode material with high capacitance but low material and energy costs. In this study, reduced graphene oxide/nickel oxide (RGO/NiO) nanocomposites were prepared using a non-aqueous solvent-based method followed by calcination. Nickel acetate tetrahydrate and tert-butanol were used as the precursor and solvent, respectively. Ultrasmall nickel oxide nanoparticles, ca. 8.0 nm in size, were deposited on the surface of the graphene sheets simultaneously with the partial reduction of graphene oxide. The resulting RGO/NiO electrode exhibited a high capacitance of 689 F g⿿1 at a current density of 0.8 A g⿿1. After 1500 cycles, the specific retention and the coulombic efficiency yielded to 86.34% and 96.39%, respectively, which supports the viability of this composite as an alternative activated material with high electrochemical performance.

The use of a biocompatible and thermoresponsive polymer, poly(2-hydroxyethyl methacrylate) (PHEMA) grafted onto the surface of graphene oxide (GO) as an adsorbent for the removal of a cationic dye ...

A hybrid nanocomposite of magnetic nanoparticles (Fe3O4) and poly(2-hydroxyethyl methacrylate)-block-poly(methyl methacrylate) (PHEMA-b-PMMA) was synthesized successfully by the atom transfer radical polymerization (ATRP) in an ionic liquid (IL), 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim]PF6). Fe3O4 nanoparticles were first surface-modified with the initiator, 2-bromoisobutyryl bromide (BiBBr), in dimethylformamide (DMF) solvent, which produced the macro-initiator, Fe3O4-BiB, to initiate the polymerization reactions for the synthesis of the block polymer, PHEMA-b-PMMA. After immobilizing the initiator on the surface of Fe3O4, the block polymer chains were grafted successfully onto the Fe3O4 surface, causing the formation of a core-shell nanostructure. The incorporation of Fe3O4 in the nanocomposite was confirmed by attenuated total reflectance-Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy. The thermal stability and magnetic properties increased with increasing amount of Fe3O4 in the nanocomposite.

Chitosan (CS)/iron oxide (Fe3O4) composites were prepared using a chemical precipitation method. The CS/Fe3O4 composite was characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, and zeta-potential measurements. The composite was used to remove methyl orange (MO) dye from an aqueous solution. The factors affecting the adsorption capacity, such as adsorption time, absorbent dosage and solution pH were investigated. The results suggested that the composite was an effective adsorbent for the removal of MO dye from its aqueous solution. Kinetics studies showed that the adsorption process was consistent with a pseudo-second- order model. The adsorbent efficiency was unaltered, even after five cycles of reuse, and the adsorbent could be recollected easily using a magnet. In addition, the composite exhibited a superior antibacterial efficacy against Escherichia coli; 82% within 24 h, as measured by the colony forming units.

Supercapacitors are an emerging energy-storage system with a wide range of potential applications. In this study, highly porous nickel-cobalt-oxide@reduced graphene oxide (Ni-Co-O@RGO-s) nanosheets were synthesized as an active material for supercapacitors using a surfactant-assisted microwave irradiation technique. The RGO-modified nanocomposite showed a larger specific area, better conductivity, and lower resistivity than the unmodified nanocomposite because the RGO facilitated faster ion diffusion/transport for improved redox activity. The synergistic effect of Ni-Co-O@RGO-s resulted in a high capacitance of 1903 F g−1 (at 0.8 A g−1) in a mixed KOH/redox active K3Fe(CN)6 electrolyte. The asymmetric Ni-Co-O@RGO-s//AC supercapacitor device yielded a high energy density and power density of 39 Wh kg−1 and 7500 W kg−1, respectively. The porous structure and combination of redox couples from both the electrode and electrolyte provided a highly synergistic effect, which improved the performance of the supercapacitor device.

In the last few years, coal mine methane (CMM) has gained significance as a potential non-conventional gas fuel. The progressive depletion of common fossil fuels reserves and, on the other hand, the positive estimates of CMM resources as a by-product of mining promote this fuel gas as a promising alternative fuel. The increasing importance of its exploitation makes it necessary to check the capability of the present-day models and equations of state for natural gas to predict the thermophysical properties of gases with a considerably different composition, like CMM. In this work, accurate density measurements of a synthetic CMM mixture are reported in the temperature range from (250 to 400) K and pressures up to 15 MPa, as part of the research project EMRP ENG01 of the European Metrology Research Program for the characterization of non-conventional energy gases. Experimental data were compared with the densities calculated with the GERG-2008 equation of state. Relative deviations between experimental and estimated densities were within a 0.2% band at temperatures above 275 K, while data at 250 K as well as at 275 K and pressures above 10 MPa showed higher deviations.

The quality and the availability of experimental data limit the achievable accuracy of multiparameter equations of state, such as the GERG-2008. Referring to the fundamentals of this wide-range equation of state, no suitable data were available for many mixtures containing helium. This work provides accurate experimental (p, ρ, T) data for three binary mixtures of methane with helium: (0.95 (amount-of-substance fraction) CH4 + 0.05 He) and (0.90 CH4 + 0.10 He) at temperatures of (240, 250 and 260) K, and (0.50 CH4 + 0.50 He) from (240 to 400) K. This work is a continuation of a previous one which reported accurate experimental (p, ρ, T) data for the (0.95 CH4 + 0.05 He) and the (0.90 CH4 + 0.10 He) binary mixtures in the temperature range from the (250 to 400) K. All density measurements were performed by using a single-sinker densimeter with magnetic suspension coupling at pressures up to 20 MPa. Experimental data were compared with the corresponding densities calculated from the GERG-2008 and the AGA8-DC92 equations of state. Deviations from the GERG-2008 are much larger than from the AGA8-DC92 (up to –6.5 %). These deviations increased with decreasing temperature, with increasing pressure, and with increasing helium fraction. In contrast, deviations from the AGA8-DC92 are within the 0.5 % band. The experimental values were also used to calculate the second interaction virial coefficient for this mixture., 2018-05-30, MEC ENE2013-47812-R, European Commission ENG54

Untersuchungen zur gasinduzierten Phasentrennung bzw. zum Aussalzen mit nahekritischen Gasen wurden an verschiedenen wassrigen Losungen (auch mit ionischem Fluid) durchgefuhrt. Ziel war der Nachweis und die Charakterisierung von Hochdruckmehrphasengleichgewichten, die sich fur eine technische Anwendung eignen. Kriterien hierfur sind Auftreten des Flussig/flussig-Phasenzerfalls bei relativ niedrigem Druck, seine Existenz uber einen weiten Druck- und Zusammensetzungsbereich und damit verbunden eine druckinduzierte Anderung der Zusammensetzung der koexistierenden Flussigphasen. Die eingesetzten ionischen Fluide zeigen zwar das gewunschte Phasenverhalten, erfullen die Kriterien aber nur teilweise. Im Vorgriff auf eine mogliche Anwendung wurde die Verteilung eines hochmolekularen, amphiprotischen Naturstoffs auf die koexistierenden Flussigphasen untersucht und durch Einstellung des pH-Werts gezielt verandert. Investigations on gas-induced phase split, i.e., salting out by a nearcritical gas, were carried out for several aqueous solutions (including an ionic liquid). The research aimed to verify and characterize high-pressure multiphase equilibria that might be suitable for technical applications. The respective criteria are occurrence at relatively low pressures and the existence of the phase equilibrium phenomenon over a significant region of both composition and pressure, which is related to a pressure-induced significant alteration of the compositions of the coexisting liquid phases. The employed ionic liquids revealed the expected phase behavior but without full compliance of all criteria. In anticipation of an application, the partitioning of an amphiprotic, high-molecular biomolecule to the coexisting liquid phases was successfully administered via a pH variation.

Correction for ‘Modified chemical synthesis of MnS nanoclusters on nickel foam for high performance all-solid-state asymmetric supercapacitors’ by Vijay S. Kumbhar et al., RSC Adv., 2017, 7, 16 348–16 359.

The solubility of a single gas as well as the simultaneous solubility of several gases in an ionic liquid is of great interest in many areas of chemical engineering, particularly in heterogeneous catalysis. One of the most interesting features involved in the study of the simultaneous solubility of several gases in a pure ionic liquid is the difference between experimental data and predictions for the simultaneous solubility (based on experimental data for the solubility of the single gases). The well soluble gas might act as a cosolvent or as an antisolvent for a sparsely soluble second gas. New experimental results and a correlation are presented for the simultaneous solubility of hydrogen (i.e., a sparsely soluble gas) and carbon dioxide (a well soluble gas) in the ionic liquid 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([hmim][Tf2N]) at temperatures between 293 K and 373 K and pressures up to about 9.2 MPa. The experimental results reveal that carbon dioxide acts as a cosolvent for hydrogen in that particular ionic liquid. A correlation shows that the cosolvency effect can be modeled by considering interaction parameters between hydrogen and carbon dioxide in liquid [hmim][Tf2N]. The correlation can also be used to quantify that cosolvency effect: one mole of carbon dioxide in 1000 g of [hmim][Tf2N] increases the solubility of (small amounts of) hydrogen by about 20%.

Experimental results are reported for the solubility of carbon dioxide in liquid mixtures of water and the ionic liquid 1-n-butyl-3-methylimidazolium methylsulfate ([bmim][CH3SO4]). Three (gas-free...

Adding some salt to a homogeneous aqueous liquid solution of an organic solvent often results in a liquid–liquid phase split. However, such a phase split can also be achieved by charging such a liq...

The high-pressure phase equilibrium of two ternary systems—(ethene + water + acetone) and (ethane + water + acetone)—was investigated by a static−analytical method. Both systems exhibit the “salting-out” phenomenon upon pressurization by the gaseous compound. The composition of the two coexisting liquid phases L1 and L2 of the high-pressure liquid−liquid−vapor (L1L2V) equilibrium was determined at (293, 313, and 333) K over the entire pressure range that spans from about (2.9 to 8.0) MPa for (ethene + water + acetone) and from about (2.3 to 5.8) MPa for (ethane + water + acetone), respectively. Additionally, the coordinates of both critical end point lines (i.e., the lower ((L1 = L2)V) and the upper (L1(L2 = V)), respectively) bordering the L1L2V equilibrium were recorded between (278 and 353) K. For both systems, it was found that, at constant temperature, increasing the pressure has a stronger impact on the L2 phase (resulting in higher contents of the gas), whereas the composition of the water-rich L1 ...

Some homogeneous liquid mixtures of an ionic liquid and a lower alkanol (e.g., methanol) can be forced to undergo a liquid–liquid phase split (resulting in a three-phase liquid–liquid–vapor (L1L2V) equilibrium) by pressurization with a gas. Such systems exhibit the phenomenon of “salting out by a nearcritical gas”. That phenomenon is often observed at temperatures around the critical temperature of the gas in liquid mixtures where at least one of the liquid components is a good solvent for that gas. New experimental results for both the L1L2V equilibrium and the corresponding critical endpoint lines of the two ternary systems (carbon dioxide + methanol + 1-n-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF6]) and (carbon dioxide + 1-butanol + 1-n-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide [hmim][Tf2N]) at temperatures between 293 and 333 K are reported. The experiments were performed with an “analytical method”. The liquid–liquid phase split exists only at pressures between a lower critical endpoint line (where both liquid phases become critical and coexist with a vapor phase) and an upper critical endpoint line (where one of the phases becomes critical with the vapor phase while the critical phases coexist with another liquid phase). The compositions of the coexisting three phases L1, L2, and V differ considerably; a high-density, ionic liquid-rich liquid phase (L1) coexists with an alkanol-rich liquid phase (L2) of lower density and a vapor phase (V) that is virtually ionic liquid-free. For both systems, it was observed that, at constant temperature, increasing pressure shifts the L1 phase towards higher contents of ionic liquid and gas and less alkanol, whereas in the L2 phase the mole fractions of ionic liquid and alkanol decrease. Higher temperatures result in a smaller difference between the pressures of both critical endpoint lines. Experimental results for both critical endpoint lines and for the compositions of the coexisting liquid phases are reported.

Two different ordered mesoporous solids, a hexagonal SBA-15 silica sample and its inverse CMK-3 carbon structure were applied in liquid-phase adsorption. By means of the analysis of experimental data of a binary liquid model mixture with one polar and one non-polar component, the general way is outlined how to obtain essential and trustworthy solid information from liquid-phase adsorption.

C. I. Disperse Red 60 (DR60) was absorbed into polymer films and textile fibers in the presence of supercritical carbon dioxide at pressures between 5 and 33MPa and at temperatures between 308.2 and 423.2 K. Polystyrene (PS) and poly(methyl methacrylate) (PMMA) films and polyester (polyethylene terephthalate: PET) and Nylon 6 textiles were used as absorbents. The amount of equilibrium sorption of dye increased both with pressure and temperature. The sorption behavior was successfully analyzed with the quasi dual-mode sorption model.

The solubility of carbon dioxide in three ionic liquids (ILs) under supercritical fluid condition was meas- ured at pressures up to 32 MPa and at temperatures of 313.15, 323.15, and 333.15 K in a high-pressure view cell. The imidazolium-derivative ionic liquids 1-butyl-3-methylimidazolium hexafluorophosphate ((bmim)(PF6)), 1-butyl-3-meth- ylimidazolium tetrafluoroborate ((bmim)(BF4)), and 1-octyl-3-methylimidazolium tetrafluoroborate ((omim)(BF4)) were employed in this research. The effects of pressure, temperature, nature of anion and cation as well as the water content on the solubility of CO2 in the ILs were investigated experimentally. The solubility of CO2 in the IL was higher for the ILs with longer cationic alkyl group and for the ILs with lower anion polarity. The lower the water content or the lower the temperature as well as the higher the pressure, the higher was the solubility of CO2.

Experimental data for the solubility of the two single gases carbon dioxide and hydrogen in the ionic liquid 1-n-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide ([bmpy][Tf 2 N]) are reported for temperatures between (293.1 and 413.2) K. The maximum pressure (the maximum gas molality in the solvent) was 10.8 MPa (4.43 mol·kg -1 ) for carbon dioxide and 8.9 MPa (0.14 mol·kg -1 ) for hydrogen. The experiments were performed using a high-pressure view-cell technique operating on the synthetic method. The solubility of carbon dioxide in [bmpy][Tf 2 N] is more than 1 order of magnitude higher than the solubility of hydrogen. Carbon dioxide becomes less soluble in [bmpy][Tf 2 N] with increasing temperature, whereas hydrogen shows the opposite effect. An extension of Henry's law is employed to correlate the solubility pressures. The final results for the Henry's constant (at zero pressure) of carbon dioxide and hydrogen in [bmpy][Tf 2 N] (on the molality scale) are represented within the experimental uncertainty (about 0.8 % for carbon dioxide and 1.3 % for hydrogen) by In(k (0) H,CO2 /MPa) = 8.5128 - 2057/(T/K) - 0.004274·(T/K) and In(k (0) H, H2 /MPa) = 3.5746 + 343/(T/K) - 0.0008·(T/K), respectively.

Experimental data for the solubility of the two single gases carbon monoxide and oxygen in the ionic liquid 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([hmim][Tf2N]) are reported for temperatures between (293.25 and 413.2) K. The maximum pressure (the maximum gas molality) was 9.8 MPa (0.27 mol·kg−1) for carbon monoxide and 9.1 MPa (0.31 mol·kg−1) for oxygen. The experiments were performed using a high-pressure view-cell technique operating on the synthetic method. Oxygen shows a slightly higher solubility than carbon monoxide under all conditions investigated, but the solubility generally remains very low. Both gases become less soluble in [hmim][Tf2N] with increasing temperature; however, the effect is not very pronounced and becomes ambiguous for carbon monoxide above 373 K. An extension of Henry’s law is employed in correlating the solubility pressures. The final results for the Henry’s constant (at zero pressure) of carbon monoxide and oxygen in [hmim][Tf2N] (on the molality scale)...

The partial molar volume of a gas that is dissolved at high dilution in a solvent is required to express the influence of pressure on Henry's constant as well as to describe the volume change (expansion) of the liquid caused by the dissolved gas. The correlations of recently published experimental results for the solubility of some selected gases (CO 2 , Xe, CH 4 , CF 4 , H 2 , CO, O 2 ) in three imidazolium-based ionic liquids (1- n -butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF 6 ]), 1- n -butyl-3-methylimidazolium methyl sulfate ([bmim][CH 3 SO 4 ]), and 1- n -hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([hmim][Tf 2 N])) determined by the synthetic method were re-evaluated by also considering the experimentally determined volumetric properties. The new evaluation does not change the published results for Henry's constants, but additionally yields reliable information on the partial molar volume of those gases in the mentioned ionic liquids at temperatures from about 293 to 413 K.

At temperatures from (289 to 353) K, the ternary system (ethene + water + 2-propanol) is known to exhibit a region of liquid−liquid−vapor (L1L2V) equilibria at elevated pressures that is bordered by the lower ((L1 = L2)V) and upper (L1(L2 = V)) critical end point lines. This particular demixing effect is commonly known as “salting out by a supercritical gas”. In this work, the effect of adding different electrolytes on the pressure of both critical end points at (293 and 333) K is investigated.

In this work, we report on the solubility of six disubstituted anthraquinone-type disperse dyes in compressed CO2 between (299 and 346) K and up to a pressure of 20 MPa determined by a flow method. The disperse dyes belong to a series of 1,4-bis(alkylamino)-9,10-anthraquinones, where alkyl = methyl, ethyl, propyl, 1-methylethyl, butyl, pentyl, and octyl. The results of the previously investigated propyl derivative were included for comparative discussion. Significant differences regarding the solubility behavior of the individual dyestuffs were observed under the applied experimental conditions. VIS spectroscopy was applied to determine solubility, and the accessible measuring range was limited by a maximum analyzable solubility of about 450·10−6 mol·dm−3. At any experimental conditions, 1,4-bis(1-methylethylamino)-9,10-anthraquinone with a branched alkyl group shows the highest solubility for that homologous series. For example, at p = 16.83 MPa and T = 310.0 K, the solubility of 1,4-bis(1-methylethylami...

Activity coefficients at infinite dilution were measured for eight alkanols (methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, and 2-methyl-2-propanol) in the three ionic liquids 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]), 1-butyl-3-methylimidazolium methyl sulfate ([bmim][CH3SO4]), and 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl) amide ([hmim][Tf2N]) between (293.15 and 353.15) K using the dilutor technique. The results are presented and, as far as possible, compared with literature data.

This work reports new experimental results for the solubility of two single gases (methane and xenon) in the ionic liquid 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([hmim][Tf2N]). The solubility was measured with a high-pressure view-cell technique operating on the synthetic method. The temperature ranged from 293.3 to 413.3 K, and the maximum pressure (the maximum gas molality) was 9.3 MPa (0.51 mol·kg-1) for methane and 9.6 MPa (2.08 mol·kg-1) for xenon. Xenon shows a significantly higher solubility than methane at all conditions investigated. Both gases become less soluble in [hmim][Tf2N] with rising temperature. An extension of Henry's law is employed to correlate the solubility pressures. The final results for the Henry's constants (at zero pressure) of methane and xenon in [hmim][Tf2N] (on the molality scale) are represented within the experimental uncertainty (about 1.2% for methane and 1% for xenon) by ln( /MPa) = 6.4929 − 835.9/(T/K) − 0.003471(T/K) and ln( /MPa) = 6.3357 − 13...

The solubility of the single gases hydrogen and carbon monoxide in the ionic liquid 1-n-butyl-3-methylimidazolium methyl sulfate ([bmim][CH3SO4]) was measured with a high-pressure view-cell technique based on the synthetic method. The temperature ranged from ∼293 to ∼413 K, and the pressure reached up to ∼9.3 MPa. The gas molality amounted up to ∼0.1 mol per kilogram of [bmim][CH3SO4]. Carbon monoxide showed a slightly better solubility than hydrogen. The (extended) Henry's law was successfully applied to correlate the solubility pressures. The final results for the Henry's constant (at zero pressure) of hydrogen and carbon monoxide in [bmim][CH3SO4] (on the molality scale) are correlated within the estimated uncertainty (±1%) by ln ( k H , H 2 ( 0 ) / MPa ) = 3.074 + 602 / ( T / K ) and ln ( k H , CO ( 0 ) / MPa ) = 5.3377 − 66.85 / ( T / K ) − 0.0019517 ( T / K ) , respectively.

Solubility measurements of methane and of xenon in the ionic liquid 1-n-butyl-3-methylimidazolium methyl sulfate ([bmim][CH3SO4]) were performed with a high-pressure view-cell technique based on the synthetic method. The temperature ranged from 293.1 K to 413.2 K, and the maximum pressure (the maximum gas molality) was 8.9 MPa (0.19 mol·kg-1) for methane and 11.3 MPa (0.65 mol·kg-1) for xenon. Both gases become less soluble in [bmim][CH3SO4] with rising temperature, but xenon shows a significantly higher solubility at all conditions investigated. An extension of Henry's law is employed to correlate the solubility pressures in both cases. The final results for the Henry's constant (at zero pressure) of methane and xenon in [bmim][CH3SO4] (on the molality scale) are correlated within the experimental uncertainty (about ± 1.3 %) by ln( /MPa) = 6.216 − 564.5/(T/K) − 0.002566(T/K) and ln( /MPa) = 5.5906 − 928/(T/K) − 0.00141(T/K), respectively.

This study reports experimental data and modeling results for the partitioning of a single solute (from two pairs of structurally similar biomolecules ( N -acetyl- d -glucosamine and N -acetyl- d -mannosamine) and ( d - as well as l -phenylalanine)) to coexisting liquid phases of the high-pressure three-phase (vapor–liquid–liquid) equilibrium (VLLE) of the ternary system (ethene + water + 2-propanol) at 293 and 333 K and at pressures up to 17 MPa. The experiments were performed with an analytical view cell at low solute concentrations (below 1.5 and 3.0 g dm −3 for the aminosugars and the phenylalanines, respectively). At such solute concentrations, the VLL-phase equilibrium of the system (ethene + water + 2-propanol) is only slightly disturbed by the low-volatile fourth compound, and the results for the partition coefficient of the solute are at nearly infinite dilution. The new experimental results are correlated using the modification of Melhem et al. for the (cubic) Peng–Robinson equation of state with two different mixing rules and estimated pure-component properties of the solutes.

This study reports experimental data and modeling results for the partitioning of 2,5-hexanediol and 2,5-hexanedione – two structurally similar biomolecules – on coexisting liquid phases of the high-pressure vapor–liquid–liquid equilibrium in the ternary system (ethene + water + 2-propanol) at 293 and 333 K and at pressures up to 17 MPa. The experiments were performed with an analytical view cell at very low solute concentrations (about 2 g dm−3), so that the phase equilibrium of the ternary system remained practically unaffected by the fourth compound and the results for the partition ratio of the solute are at nearly infinite dilution. The new experimental results are correlated using the modification of Melhem et al. for the Peng–Robinson equation of state with two different mixing rules and estimated pure component parameters of the solutes.

Innovación Educativa, The basis for the development and evaluation of equations of state for mixtures is experimental data for several thermodynamic properties. The quality and the availability of experimental data limit the achievable accuracy of the equation. Referring to the fundamentals of GERG-2008 wide-range equation of state, no suitable data were available for many mixtures containing secondary natural gas components. This work provides accurate experimental (p, ρ, T) data for two binary mixtures of methane with helium (0.95 (amount-of-substance fraction) CH4 + 0.05 He and 0.90 CH4 + 0.10 He). Density measurements were performed at temperatures between 250 K and 400 K and pressures up to 20 MPa by using a single-sinker densimeter with magnetic suspension coupling. Experimental data were compared with the corresponding densities calculated from the GERG-2008 and the AGA8-DC92 equations of state. Deviations from GERG-2008 were found within a 2 % band for the (0.95 CH4 + 0.05 He) mixture but exceeded the 3 % limit for the (0.95 CH4 + 0.05 He) mixture. The highest deviations were observed at 250 K and pressures between 17 and 19 MPa. Values calculated from AGA8-DC92, however, deviated from the experimental data by only 0.1 % at high pressures and exceeded the 0.2 % limit only at temperatures of 300 K and above, for the (0.90 CH4 + 0.10 He) mixture., MEC ENE2013-47812-R, Junta de Castilla y León Regional VA391A12-1, European Commission's ENG54