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As a promising hydrogen storage material, the practical application of magnesium is obstructed by the stable thermodynamics and sluggish kinetics. In this paper, three kinds of NiTiO3 catalysts with different mole ratio of Ni to Ti were successfully synthesized and doped into nanocrystalline Mg to improve its hydrogen storage properties. Experimental results indicated that all the Mg-NiTiO3 composites showed prominent hydrogen storage performance. Especially, the Mg-NiTiO3/TiO2 composite could take up hydrogen at room temperature and the apparent activation energy for hydrogen absorption was dramatically decreased from 69.8 ± 1.2 (nanocrystalline Mg) kJ/mol to 34.2 ± 0.2 kJ/mol. In addition, the hydrogenated sample began to release hydrogen at about 193.2 °C and eventually desorbed 6.6 wt% H2. The desorption enthalpy of the hydrogenated Mg-NiTiO3-C was estimated to be 78.6 ± 0.8 kJ/mol, 5.3 kJ/mol lower compared to 83.9 ± 0.7 kJ/mol of nanocrystalline Mg. Besides, the sample revealed splendid cyclic stability during 20 cycles. No obvious recession occurred in the absorption and desorption kinetics and only 0.3 wt% hydrogen capacity degradation was observed. Further structural analysis demonstrates that nanosizing and catalyst doping led to a synergistic effect on the enhanced hydrogen storage performance of Mg-NiTiO3-C composite, which might serve as a reference for future design of highly effective hydrogen storage materials.

Carbon materials have excellent catalytic effects on the hydrogen storage performance of MgH2. Here, carbon-supported Ni3S2 (denoted as Ni3S2@C) was synthesized by a facile chemical route using ion exchange resin and nickel acetate tetrahydrate as raw materials and then introduced to improve the hydrogen storage properties of MgH2. The results indicated the addition of 10 wt.% Ni3S2@C prepared by macroporous ion exchange resin can effectively improve the hydrogenation/dehydrogenation kinetic properties of MgH2. At 100 °C, the dehydrogenated MgH2 Ni3S2@C-4 composite could absorb 5.68 wt.% H2. Additionally, the rehydrogenated MgH2 Ni3S2@C-4 sample could release 6.35 wt.% H2 at 275 °C. The dehydrogenation/hydrogenation enthalpy changes of MgH2 Ni3S2@C-4 were calculated to be 78.5 kJ mol−1/−74.7 kJ mol−1, i.e., 11.0 kJ mol−1/7.3 kJ mol−1 lower than those of MgH2. The improvement in the kinetic properties of MgH2 was ascribed to the multi-phase catalytic action of C, Mg2Ni, and MgS, which were formed by the reaction between Ni3S2 contained in the Ni3S2@C catalyst and Mg during the first hydrogen absorption–desorption process.

The solubilities of the rare earth chlorides REECl3, where REE = (La, Nd, Er), were measured in HCl bearing water vapor from 350 to 425 °C with water partial pressures ranging from 8 to 170 bar. Solubility data were fit to the Pitzer-Pabalan quasi-chemical model in order to extract thermodynamic parameters for the formation of the gaseous REE-chloride-water clusters REECl3(H2O)n. The data show that the solubility of the REE chlorides are orders of magnitude higher than salts such as NaCl or CuCl at low water fugacities, despite their sublimation energies being substantially higher. This enhanced solubility is likely due to the high enthalpy associated with binding a single water molecule to form the species REECl3(H2O), with derived enthalpies ranging from −378 to −465 kJ/mol. Addition of further water molecules to form higher order clusters (n > 1) involves enthalpy changes of ~−20 kJ/mol, and are in effect thermodynamically suppressed over the temperature range 350–425 °C. Despite the enhanced solubility of small REECl3 water clusters, simulations of boiling processes demonstrate that the REE show highly conservative behavior, partitioning strongly into the dense aqueous phase. Not surprisingly, the presence of phosphates in the system makes this effect even more pronounced, completely immobilizing the REE. This would reduce transport in both the vapor and aqueous phase to negligible levels. However, we suggest that vapor phase transport of the REE may play a significant role in systems having a relatively low partial pressure of water (below the saturation point), where the relatively high stability of the first hydrated REE chloride clusters (REECl3(H2O) and REECl3(H2O)2) will give a preference for gas transport of the REE relative to other elements. This can likely happen in systems involving a gas/melt exchange in fumarolic exhalations, where water vapor discharges at relatively low (close to atmospheric) pressures.

2,4(5)-Dinitroimidazole (2,4(5)-DNI) is an important energetic material, and it is also an important precursor for the preparation of drugs and energetic materials. In this study, the solubility of 2,4(5)-DNI in eleven pure solvents (chlorobenzene, benzene, 1,2-dichloroethane, toluene, water, isopropyl alcohol, ethyl acetate, acetonitrile, methanol, 1,4-dioxane and acetone) were measured by using a dynamic test method from 278.15 K to 323.15 K under 101.1 kPa. Four solubility models were used to fit the experimental data, which were ideal model, modified Apelblat equation, polynomial empirical equation, and λh equation. Meanwhile, the relative average deviation and root-mean-square deviation between the experimental data and the fitted data were also calculated. Furthermore, the three thermodynamic parameters, i.e., dissolution enthalpy, dissolution entropy and Gibbs energy were obtained based on solubility data. Finally, the crude product of 2,4(5)-DNI was crystallized with acetone as solvent, and the purity of the crystalline product was greater than 99.5%.

This work aims to evaluate the dynamic performance of a highly selective Ni-based surface during the oxidative dehydrogenation of ethane (ODH-C2). The catalyst comprises an in-house bimetallic mixed-oxide formulation with a Ni/Sn atomic ratio of 10. To corroborate its proper synthesis, it is characterized by TGA, AES, XRD, physisorption of N2 and TEM. The catalytic evaluation of the mixed oxide under dynamic conditions allows the proposition of a redox surface mechanism whose reliability is evaluated through a rigorous analysis, which is based on the development of a kinetic model and a robust experimentation program using a fully-automated micro-reaction unit and registering in-situ surface temperatures and continuous inline monitoring of oxygen and carbon dioxide. Experiments are carried out using a mixture of ethane or ethylene, oxygen and nitrogen as feedstock, at temperatures from 360 to 480 °C, total pressures from 100 to 500 kPa, and space-time values from 8.1 to 133.1 kgcat s molC2H6−1. Oxygen conversion ranges from 5% to 100% while the one for ethane varies from 5% to 60%. Besides, the selectivity and yield to ethylene vary from 30% to 90% and from 2% to 40%, respectively. The suitability of the redox mechanism is here assessed by evaluating statistical and phenomenological foundations, including Boudart’s criteria. Kinetic parameters, estimated by non-linear regression and using the reparametrized form of the Arrhenius and van’t Hoff equations, are phenomenologically well founded, such that changes of entropy and enthalpy of adsorption correctly describe the loss of mobility due to adsorption and the exothermic nature of the adsorption processes. Ethylene formation is the reaction demanding the lowest activation energy (Ea1 = 61.94 kJ mol−1), while the total oxidation of ethane is the path requiring the largest activation energy (Ea2 = 132.6 kJ mol−1). Concerning the adsorption enthalpy, ethylene exhibits the largest value ( − Δ H C 2 H 4 ° = 123.39 kJ mol−1), while carbon dioxide presents the lowest one ( − Δ H C O 2 ° = 42.00 kJ mol−1). Additional findings can be summarized as follows: activity and selectivity are recovered after the dynamic operation under oxidative conditions of the catalytic surface; carbon dioxide is identified as the only no desired byproduct; and hydroxyl surface species lead to the formation of water which affects the selectivity to ethylene, as well as the reaction rates. These findings are of interest for future studies directed at elucidating the performance of the Ni-based catalyst at larger scales, paving the way for the efficient design of the industrial reactor for the ODH-C2.

Studies on the degradation process of waste polyethylene terephthalate (PET) have become increasingly mature, but there are relatively few studies on the separation of degradation products. The products contain many components and the separation of which is difficult. Therefore, the study on phase equilibrium thermodynamics of bis-2-hydroxyethyl terephthalate (BHET) is of great theoretical significance and practical value to provide basic data for the BHET crystallization separation. In this work, the degraded products were purified and characterized. The solubility of BHET in methanol, ethanol, ethylene glycol, water and the mixture of ethylene glycol+water were determined by static method. The experimental results were correlated with different models, such as IS model, λh equation, Apelblat equation and NRTL model. Based on the Van't Hoff equation, the mixing Gibbs energy, enthalpy and entropy were calculated. From this work, the basic data which can be used to guide the crystallization process of BHET were obtained, including solubility data, correlation model and thermodynamic properties

Magnesium hydride (MgH2) is a potential material for solid-state hydrogen storage. However, the thermodynamic and kinetic properties are far from practical application in the current stage. In this work, two-dimensional vanadium carbide (V2C) MXene with layer thickness of 50−100 nm was fist synthesized by selectively HF-etching the Al layers from V2AlC MAX phase and then introduced into MgH2 to improve the hydrogen sorption performances of MgH2. The onset hydrogen desorption temperature of MgH2 with V2C addition is significantly reduced from 318 °C for pure MgH2 to 190 °C, with a 128 °C reduction of the onset temperature. The MgH2 + 10 wt% V2C composite can release 6.4 wt% of H2 within 10 min at 300 °C and does not loss any capacity for up to 10 cycles. The activation energy for the hydrogen desorption reaction of MgH2 with V2C addition was calculated to be 112 kJ mol−1 H2 by Arrhenius's equation and 87.6 kJ mol−1 H2 by Kissinger's equation. The hydrogen desorption reaction enthalpy of MgH2 + 10 wt% V2C was estimated by van't Hoff equation to be 73.6 kJ mol−1 H2, which is slightly lower than that of the pure MgH2 (77.9 kJ mol−1 H2). Microstructure studies by XPS, TEM, and SEM showed that V2C acts as an efficient catalyst for the hydrogen desorption reaction of MgH2. The first-principles density functional theory (DFT) calculations demonstrated that the bond length of Mg−H can be reduced from 1.71 A for pure MgH2 to 2.14 A for MgH2 with V2C addition, which contributes to the destabilization of MgH2. This work provides a method to significantly and simultaneously tailor the hydrogen sorption thermodynamics and kinetics of MgH2 by two-dimensional MXene materials.

The equilibrium solubility of 2,4-diaminobenzenesulfonic acid and super solubility as well as metastable zone width were measured in (H2SO4+ H2O) system by the laser dynamic method at elevate temperature range from 298.15 K to 338.15 K. 2,4-diaminobenzenesulfonic acid solubility dependence on the temperature and solvent composition were correlated by the modified Apelblat equation, (CNIBS)/Redlich-Kister model and Jouyban-Acree model. The correlated results by three correlation models were in good accord with the experimental values according to relative average deviations (RD), root-mean-square deviations (RMSD), and correlation coefficients (R2). The metastable zone width increased with temperature and sulfuric acid content. The dissolution enthalpy, dissolution entropy and the Gibbs energy were calculated from the experimental values, which indicated that dissolution process of the 2,4-diaminobenzenesulfonic acid was endothermic. The solubility and calculation models of 2,4-diaminobenzenesulfonic acid in (sulfuric acid +water) system could provide the basic data to the crystallization and purifying of the 2,4-diaminobenzenesulfonic acid.

Methanol has been used to prevent hydrate formation in industrial handling of hydrate forming mixtures containing water for many decades. Ethanol is also used for the same purpose in countries that have easy access to low price ethanol, like for instance Brasil. Common to these small alcohols is that they also have surfactant properties that will promote hydrate formation, but when added to water in sufficient amounts the hydrate prevention characteristics will dominate. These alcohols will primarily prevent heterogeneous hydrate formation on the interface between water and a separate hydrate phase. Alcohol effects on both of these routes to hydrate formation are investigated and compared to experimental data. In particular we also investigate the effects of these small alcohols on Gibbs free energy for the hydrate formed on the new, shifted, stability conditions. Gibbs free energy is generally higher than hydrate formed from pure water. Enthalpies of hydrate formation are also higher for hydrate formed from water containing alcohols. These are negative numbers so in absolute values released formation enthalpy is lower. The presence of these alcohols in water will also prevent homogeneous hydrate formation from dissolved hydrate formers in water. Glycols have more important roles in other routes to hydrate nucleation. Heterogeneous hydrate nucleation towards mineral surfaces is feasible in different ways. Polar hydrate formers like H2S and CO2 can adsorb directly on rust, and as discussed here, is able to form hydrate from adsorbed state on rust surface. Non-polar hydrocarbons like for instance methane might get trapped in structured water and then nucleate to hydrate. Some research on this is published and further research is in progress. Glycols have very strong attraction to rust and corresponding chemical potentials for adsorbed glycols on rust are favourable enough to facilitate phase transition from glycols dissolved in water over to adsorption. Injection of glycol in gas processing plants have been used by industry for many years and in many cases it might even be economically and technically feasible compared to expensive drying units. Exceptions are situations that will lead to water/glycol freezing. But even in multiphase transport of hydrocarbons with various water cuts mixtures of alcohols might be a technically efficient solution in which the small alcohols may be very efficient ass discussed above and glycols may go through adsorption phase transition from water solution over to glycol film on rust and as such prevent hydrate nucleation towards rust surface. This possible strategy requires more theoretical work as well as experimental investigation. On the basis of thermodynamic analysis and calculations of hydrate formation from different routes it is argues that real natural and industrial systems are unable to reach thermodynamic equilibrium. It is therefore a need for a consistent thermodynamic platform with a uniforms reference system for all phases. We propose, and demonstrate, a residual thermodynamic model system for all phases.

High hydrogen desorption temperature and sluggish reaction kinetics are the major limitations for the practical application of MgH2. In this study, Co particles with a face centered cubic (FCC) structure and a hexagonal close packed (HCP) structure were prepared facilely and proved to be good catalysts for magnesium hydride. Co particles with FCC structure presented better catalytic effect on MgH2 than that with HCP structure. Both 7% (mass) Co FCC and HCP particle modified MgH2 decreased the initial dehydrogenation temperature from 301.3 °C to approximately 195.0 °C, but 7% (mass) Co with FCC structure modified MgH2 has a faster desorption rate, and around 6.5% (mass) H2 was desorbed in 10 min at 325 °C. Hydrogen uptake was detected at 70 °C under 32.5 bar hydrogen pressure and 6.0% (mass) H2 was recharged in 40 min at 150 °C. The hydrogen desorption and absorption activation energy for 7% (mass) FCC Co modified MgH2 was significantly decreased to 76.6 (±8.3) kJ·mol−1 and 68.3 (±6.0) kJ·mol−1, respectively. Thermodynamic property was also studied, the plateau pressures of MgH2+7% (mass) FCC Co were determined to be 0.14, 0.28, 0.53 and 0.98 MPa for 300 ℃, 325 ℃, 350 ℃ and 375℃. The decomposition enthalpy of hydrogen (ΔH) for MgH2+7% (mass) FCC Co was 80.6 (±0.1) kJ·mol−1 , 5.8 kJ·mol−1 lower than that of as-prepared MgH2. Moreover, cycling performance for the first 20 cycles revealed that the reaction kinetics and capacity of MgH2-FCC Co composite remained almost unchanged. The result of density functional theory calculation demonstrated that cobalt could extract the Mg-H bond and reduced the decompose energy of magnesium hydride. Our paper can be presented as a reference for searching highly effective catalysts for hydrogen storage and other energy-related research fields.

RM3 compounds (R = rare earth metals, M = transition metals) have rarely been studied for gaseous hydrogen storage applications because of unfavorable thermodynamics. In this work, the hydrogen storage properties of a single-phase YFe3 alloy were improved by non-stoichiometric composition and alloying with Sc and Zr. Only the Y1.1–yScyFe3 (y = 0.22, 0.33) alloys consist of a single rhombohedral phase. The Sc substitution for Y leads to the reduction in the unit cell volume of the YFe3 phase, and thus significantly increases the dehydriding equilibrium pressure and decreases the dehydrogenation temperature. The alloy Y0.77Sc0.33Fe3 delivers a decomposition enthalpy change of 33.54 kJ/mol and a lowest dehydrogenation temperature of 135 °C, in comparison with 38.99 kJ/mol and 165 °C for the alloy Y1.1Fe3. The Zr substitution causes a similar thermodynamic destabilization effect, but the composition and microstructure of Y–Zr–Fe alloys need to be further optimized.

A new methodology was proposed to determine the dispersive component of the surface energy ${\gamma}_s^d$ of a solid taking into account the effect of the temperature on the surface area of n-alkanes, methylene group (${a}_{- CH2-}$) and polar molecules, thus defeating the method used by Dorris–Gray Schultz et al. We determined the correct ${\gamma}_s^d$ of the surface energy, the specific free energy, enthalpy and entropy of adsorption of polar molecules as well as the acid base constants of silica particles with an excellent accuracy. We confirmed the dependence of the dispersive component of the surface energy on the variations of the surface areas of organic molecules used in IGC technique at infinite dilution. The specific properties of interactions of silica particles were determined. The new proposed model took into account this thermal effect. Obtained results proved that the other used IGC methods gave inaccurate values of the specific parameters of silica surface, except for the vapor pressure method that led to excellent results of the specific free energy, enthalpy and entropy of adsorption, and the acid–base constants of the silica particles.

To gain better insight into the influence of the anion size and symmetry on the transport properties and thermal stability of an electrolyte based on lithium (fluorosulfonyl)(trifluoromethanesulfonyl)-imide (FTFSI) salt, we performed the physical and electrochemical characterization of an electrolyte based on FTFSI incorporated in standard binary (3EC/7EMC) and ternary (EC/PC/3DMC) alkylcarbonate mixtures. By applying the Jones-Dole-Kaminsky (JDK), Eyring and Arrhenius empirical models to the electrolyte viscosity we show that the activation enthalpy and entropy energy barriers ( Δ H ≠ , Δ S ≠ ) for viscous flow are between 12 and 15 kJ·mol−1. They are strongly dependent on the solvent nature and are significantly lower than their symmetric anions LiFSI and LiTFSI (19–20 kJ·mol−1) in the binary mixture. Furthermore, the hydrodynamic radius, rs, calculated by JDK, and the ionicity behavior illustrated by the Walden role, showed that the FTFSI anion is outside the solvation sphere (rs > 0.6 nm) which is smaller in the case of an EC/EMC solvent base. In the 3EC/7EMC solvent mixture, LiFTFSI is less conductive than in the ternary mixture i.e., σmax = 8.9 mS cm−1 at Cmax = 1.1 mol L−1 for 3EC/7EMC and, σmax = 10.5 mS cm−1 at max = 0.7 mol L−1 for EC/PC/3DMC, due to a strong solvation and a greater association of FTFSI ions in the binary solvent mixture. The thermal stability of FTFSI based electrolytes was determined by the shift of the evaporation temperature of the volatile solvents (DMC, EMC) in the presence of salt, towards the higher temperatures. This feature is visible on the thermograms obtained by DSC both with the liquid electrolyte and with charged LMO cathodes in presence of electrolytes. The consequences of these properties on the electrochemical behavior of a graphite (Gr) half-cell, a lithium metal (Li) anode and a manganese lithium oxide (LMO) cathode demonstrated on the one hand the formation of a thick solid electrolyte interphase (SEI) on graphite that consumed a significant amount of lithium i.e., 18% of total capacity of the first charge. Furthermore, LiFTFSI delivered 95% of the initial capacity C = 360 mAh g−1 at C/10 with EC/PC/3DMC versus 91% when it was combined with 3EC/7EMC C = 348 mAh g−1, while the capacities obtained for LiTFSI in EC/PC/3DMC were the lowest (C = 275 mAh g−1) compared to those of the other salts. After 10 cycles, the capacity loss at C/20 is

In this work, the effect of Inca peanut seed albumin fraction (IPA) on the rheological, thermal and microstructural properties of native corn starch (NCS) was firstly studied. Compared to the NCS, IPA addition could obviously decrease the transparency of NCS, and the transparency of NCS and NCS-IPA suspensions decreased during the storage time. The textural paraments of NCS pastes with or without IPA reached to the maximum at a concentration of 5%. Steady shear rheological tests showed that all systems were non-Newtonian fluid, and the consistency coefficient (K) values reached to the maximum at 5% IPA concentration. The storage and loss modulus values of NCS-IPA pastes were higher than those of NCS pastes, and curves of loss angle (tan δ) indicated that all pastes were typical weak gel. With the increasing addition of IPA, DSC analysis showed that the thermal properties (To, Tp and Tc) of NCS were significantly changed, whereas, there was no distinct difference in the enthalpy. Microscopy illustrated that there were some wrinkle shrinkage and severe folds on the NCS-IPA granules. Fourier-transform infrared (FT-IR) spectroscopy showed that the hydrogen bonding was primarily interaction forces between IPA and NCS molecules.

Ruscogenin, a kind of steroid saponin, has been shown to have significant anti-oxidant, anti-inflammatory, and anti-thrombotic characteristics. Furthermore, it has the potential to be employed as a medicinal medication to treat a variety of acute and chronic disorders. The interaction of a drug molecule with cell membranes can help to elucidate its system-wide protective and therapeutic effects, and it's also important for its pharmacological activity. The molecular mechanism by which ruscogenin affects membrane architecture is still a mystery. Ruscogenin's interaction with zwitterionic dipalmitoyl phosphatidylcholine (DPPC) and anionic dipalmitoyl phosphatidylglycerol (DPPG) multilamellar vesicles (MLVs) was studied utilizing two non-invasive approaches, including: Fourier Transform Infrared (FTIR) spectroscopy and Differential Scanning Calorimetry. Ruscogenin caused considerable alterations in the phase transition profile, order, dynamics and hydration state of head groups and glycerol backbone of DPPC and DPPG MLVs at all concentrations. The DSC results indicated that the presence of ruscogenin decreased the main phase transition temperature (Tm) and enthalpy (?H) values of both membranes and increased half height width of the main transition (?T1/2). The FTIR results demonstrated that all concentrations (1, 3, 6, 9, 15, 24 and 30 mol percent) of ruscogenin disordered the DPPC MLVs both in the gel and liquid crystalline phases while it increased the order of DPPG MLVs in the liquid crystalline phase. Moreover, ruscogenin caused an increase in the dynamics of DPPC and DPPG MLVs in both phases. Additionally, it enhanced the hydration of the head groups of lipids and the surrounding water molecules implying ruscogenin to interact strongly with both zwitterionic and charged model membranes. © 2022 Elsevier Inc., Ege Üniversitesi: FGA-2021-22592, This work was supported by Ege University Scientific Research Projects Coordination. (Project number is FGA-2021-22592)., This work was supported by Ege University Scientific Research Projects Coordination . (Project number is FGA-2021-22592 ).

Studying complexation between a wide variety of drugs and clay is of high importance in expanding the knowledge about controlled drug delivery and its exploitation. This study reports the use of isothermal calorimetry (ITC) in understanding the complexation process occurring between magnesium aluminium silicate (MAS) and metformin hydrochloride (MET), as a potentially controlled release drug delivery system.To fully characterise and understand the complexes formed between MAS and MET and how that might impact on controlled release systems.MAS and MET complex dispersions and particles were formulated and analysed using ITC, DSC, XRPD, ATR-FTIR, SEM/EDX, digital microscopy and 2D-SAXS.The calorimetric results confirmed the binding between MET and MAS at various pHs (5, 7 and 9) and temperatures (25 ºC and 37 ºC). The overall change in enthalpy was found to be exothermic with a comparatively small entropic contribution to the total change in Gibbs free energy, implying that the binding was an enthalpically driven process. These findings suggest that the binding process was dominated by hydrogen bonding and electrostatic interactions. pH and temperature variation did not have a great impact on the binding, as observed from the similarity in enthalpy (ΔH), entropy (ΔS) or Gibbs free energy (ΔG), with the reaction being only slightly more exothermic at pH 5 and at 37 ºC. 2D-SAXS was able to differentiate between MAS particulates and MAS-MET complexes when analysed in their liquid form suggesting the importance of appropriate methodology and instrumentation used in characterisation.ITC was successfully used in understanding the complexation process occurring between MAS and MET. Care and consideration however should thus be taken in the accurate determination and characterisation techniques for the formation of complexes for controlled release using MAS.

Enantioseparation of three β-blockers, i.e., atenolol, metoprolol and propranolol, was studied on amylose tris(3-chloro-5-methylphenylcarbamate) immobilized chiral stationary phase using supercritical fluid chromatography (SFC). The effect of organic modifiers (methanol, isopropanol and their mixture), column temperature and back pressure on chiral separation of β-blockers was evaluated. Optimum chromatographic separation with respect to resolution, retention, and analysis time was achieved using a mixture of CO2 and 0.1% isopropyl amine in isopropanol: methanol (50:50, V/V), in 75:25 (V/V) ratio. Under the optimized conditions, the resolution factors (Rs) and separation factors (α) were greater than 3.0 and 1.5, respectively. Further, with increase in temperature (25–45 °C) and pressure (100–150 bars) there was corresponding decrease in retention factors (k), α and Rs. However, a reverse trend (α and Rs) was observed for atenolol with increase in temperature. The thermodynamic data from van't Hoff plots revealed that the enantioseparation was enthalpy driven for metoprolol and propranolol while entropy driven for atenolol. To understand the mechanism of chiral recognition and the elution behavior of the enantiomers, molecular docking studies were performed. The binding energies obtained from simulation studies were in good agreement with the elution order found experimentally and also with the free energy values. The method was validated in the concentration range of 0.5–10 μg/mL for all the enantiomers. The limit of detection and limit of quantitation ranged from 0.126 to 0.137 μg/mL and 0.376–0.414 μg/mL, respectively. The method was used successfully to analyze these drugs in pharmaceutical preparations., Graphical abstract Image 1, Highlights • Simultaneous enantioseparation of three β-blockers in a single analysis using chiral SFC • Separation efficiency was mainly dependent on the nature and composition of mobile phase • van't Hoff plots revealed enthalpy driven process for metoprolol and propranolol and entropy driven for atenolol • Binding energies from molecular docking study were in good agreement with the elution order • The results suggested hydrogen bonding and hydrophobic interactions, as the dominant interaction modes.

A hydrogen liquefaction concept with an innovative configuration and a capacity of 4 kg·s−1 (345.6 Ton per day) is developed. The concept involves an ammonia absorption refrigeration system for the pre-cooling of hydrogen and MR streams from 25 °C to −30 °C. The ammonia absorption refrigeration system is fed by exhaust gases of the Parand gas power plant that are normally dissipated to the environment with a temperature of 546 °C. The simulation is performed by Aspen HYSYS V9.0, using two separate equations of state for simulating hydrogen and MR streams to gain more accurate results especially for ortho-para conversion. Results show that conversion enthalpy estimated by Aspen HYSYS, fits very well to the experimental data. Determining the important independent variables and composition of MRs are done using trial and error procedure, a functional and straightforward method for complicated systems. The minimum temperature limit in the cooling section is lowered, and an ortho-para converter is implemented in this section. The proposed concept performs well from energy aspects and leads to COP and SEC equal to 0.271 and 4.54 kW·h·kg-1, respectively. The main advantage of this study is in the low SEC, eliminating the losses of the distribution network, and improving the ability of the hydrogen liquefaction for energy storage in off-peak times.

Molecular dynamics simulations are used to compare the forces and Gibbs free energies associated with bringing small hydrophobic and hydrophilic solutes together in an aqueous solution at different temperatures between 280 and 360 °K. For the hydrophilic solutes, different relative orientations are used to distinguish between direct, intersolute hydrogen bonds (Hbond) and solutes simultaneously hydrogen bonding to a solvent water bridge. Interestingly, the temperature dependence of the hydrophobic and directly hydrogen bonding solutes turns out to be opposite to that of the bridged hydrophilic solutes, with the [Formula: see text] becoming more negative for the former and less negative for the latter with increasing temperature. Dissection of the free energy curves into enthalpy and entropy contributions, and further separation of the enthalpy term into solute-solute, solute-solvent, and solvent-solvent components provides insight into the physical molecular causes for the distinctive thermodynamic results. Finally, it is reasoned how the opposite temperature dependencies of the two types of hydrophilic interactions provide a rationale for the cold denaturation of proteins.

The influence of inulin (IN) on pasting, thermal, rheological properties, and in vitro digestibility of pea starch gel was investigated. Results showed that as the concentration of IN in PS increased, the pasting temperature of PS gradually increased, while the value of peak viscosity, breakdown, and setback decreased. Rheological test suggested that all PS-IN gels were typical non-Newtonian fluids and exhibited a solid-like behavior. With the increased concentration of IN, hardness, chewiness, and gumminess of PS-IN gels significantly declined, in which the minimum value was at addition level of 20%. The presence of IN increased the gelatinization temperatures of PS-IN gels, while decreased the gelatinization enthalpy. Fourier-transform infrared spectroscopy (FT-IR) results indicated that no covalent bonding but intermolecular hydrogen bonding occurred between PS and IN. No influence of IN on the diffraction peak of PS after pasting was confirmed by X-ray diffraction analysis. In addition, IN decreased the content of rapidly and slowly digestible starch of PS, while increasing the content of resistant starch. These results will expand the application range of PS, and also provide a theoretical basis for the development of inulin-starch based products.

We report the isolation of vanadium(II) in a metal-organic framework (MOF) by the reaction of the chloride-capped secondary building unit in the all-vanadium(III) V-MIL-101 (1) with 1,4-bis(trimethylsilyl)-2,3,5,6-tetramethyl-1,4-dihydropyrazine. The reduced material, 2, has a secondary building unit with the formal composition [VIIV2III], with each metal ion presenting one open coordination site. Subsequent reaction with O2 yields a side-on η2 vanadium-superoxo species, 3. The MOF featuring V(III)-superoxo moieties exhibits a mild enhancement in the isosteric enthalpy of adsorption for methane compared to the parent V-MIL-101. We present this synthetic methodology as a potentially broad way to access low-valent open metal sites within MOFs without causing a loss of crystallinity or porosity. The low-valent sites can serve as isolable intermediates to access species otherwise inaccessible by direct synthesis.

In this work, a comprehensive and systematic study on synergistic effect and kinetics of three coal ranks (anthracite coal, bituminous coal, and waste coal), and three biomass materials (wheat straw, sawdust, groundnut) were performed under different blending ratios. The kinetic parameters of coal and biomass devolatilization were estimated by means of thermogravimetric analysis (TGA) at 10, 20, 30 and 40 Kmin−1. These kinetic parameters were subsequently validated using Artificial Neural Network (ANN) Model. Further, for fitting the experimental data, a numerical approach to distributed activation energy model (DAEM) has been evaluated and the experimental findings were compared with simulated data. Subsequently, the kinetic and thermodynamic parameters were estimated and compared with three model-free methods viz., KAS, OFW, and Friedman. The results from TG study indicate that the interactions between the waste coal with higher rank coal and biomass samples present an inhibitive effect during the devolatilization process. Furthermore, the values of activation energy were found in the range of 270, 250, 149 kJmol−1 by using OFW, KAS and Friedman model, respectively. Additionally, the thermodynamic parameters viz., enthalpy (ΔH), Gibbs free energy (ΔG) and entropy (ΔS) were estimated as 275.2 kJ mol−1, 184.5 kJmol−1, and 59.7 Jmol−1, respectively.

The present study was conducted to assess the effects of different fluences of Nd:YAG pulsed laser irradiation on the kernel thermodynamic attributes and biophoton emission in relation with the changes in kernel metabolites during kernel germination. Significant changes in kernel internal energy, enthalpy change, entropy generation, entropy generation ratio, entropy flux, entropy flux ratio, and biophoton emission were observed. Lower laser fluences (200, 400 and 600 J/cm2) positively influenced these attributes in association with a rapid increase in kernel chlorophyll (Chl.), carotenoids (Car.), total soluble sugar (TSS), total reducing sugar (TRS), total free amino acids (TFAA) and free fatty acids (FFA) contents as compared to non-treated ones but the opposite was true at higher fluences (800 J/cm2 and above). Correlations and PCA analysis were performed for the studied attributes that showed strong negative correlations of kernel Chl., Car., TSS, TRS, TFAA and FFA with kernel TSP and oil contents that confer the breakdown of kernel reserves and this conversion was faster at low laser fluences. In conclusion, 200 and 400 J/cm2 fluences have been found the most beneficial ones as kernel treatment in maize for better metabolic activities to improve the germination.

Amaranth dye (AD) is trisodium (4E)-3-oxo-4-[(4-sulfonato-1- naphthyl) hydrazono] naphthalene-2, 7-disulfonate and anionic in nature. In the present investigation, waste biomasses such as Terminalia chebula shell (TCS), Peltophorum pterocarpum leaf (PPL) and Psidium guajava bark (PGB) are explored as biosorbents for the first time toward the removal of AD from aqueous solution in a batch method. Influence of biosorption parameters such as pH, initial concentration of AD, biosorbents (TCS, PPL, PGB) dosage, temperature and contact time was studied. Biosorption equilibrium data was analyzed using two parameter isotherms. The kinetics of the biosorption process was analyzed using different models to understand the rate-determining step. The results of the biosorption experiment and modeling investigation illustrated that the pseudo-second-order rate equation fits the experimental data and further the experimental results showed Langmuir isotherm fitted well the biosorption equilibrium data. TCS showed more efficiency toward the removal of AD than PPL and PGB. The value of enthalpy for TCS is 1.527 kJ/mol suggests that the AD removal process is endothermic. The positive value of entropy is 6.429 J/mol K indicates that the particle is randomly disordered and negative values of standard Gibbs free energy (ΔG°) suggested that the biosorption process is spontaneous.Novelty statementBiomasses of Terminalia chebula shell (TCS), Peltophorum pterocarpum leaf (PPL) and Psidium guajava bark (PGB) reported as first time explored biosorbent for amaranth dye (AD) removal from aqueous solution.Optimal biosorption parameter for AD removal determined.Experimental data examined using isotherm, kinetic and thermodynamic analysis.

Extensive all-atom molecular dynamics studies of polyethylene glycol (PEG2000) when solvated and in the polymer bulk condensed phases were performed across a wide temperature range. We proposed two modified all-atom force field and observed the fate of the PEG2000 macromolecule when solvated in water, water with 4% ethanol, and ethyl acetate. In aqueous solutions, the macromolecule collapsed into a prolate spheroidal ball-like structure while adopting a rather elongated coiled structure in ethyl acetate. Inspection of the polymer-condensed phases across the 150-340 K temperature range enabled the atomistic view of the solid glass below the glass transition temperature of 230 K < Tg < 250 K and the rubber behavior above Tg. Predicted properties include the enthalpy, density, and cohesive energy temperature behavior, the specific heat, thermal expansivity, thermal compressibility, bulk modulus, and Hildebrand solubility parameter both below and above Tg. Within the polymer matrix, the PEG2000 macromolecules were entangled displaying a wide distribution of sizes that persisted when transitioning from the glass to the rubbery phases. Calculated properties agree very well with experiments when available or stand as crucial predictions while awaiting experimental measurement. Understanding the thermodynamics and structure of this useful polymer enables the efficient prediction of its behavior when building novel composite materials for nanomedicine and nanotherapeutics.

Intermolecular interactions of the new drug candidate sila-ibuprofen are investigated in the crystal and in the enzyme cyclooxygenase-II., Sila-ibuprofen is a new potential nonsteroidal anti-inflammatory drug which deviates from its parent ibuprofen in terms of the electrostatic potential around the carbon/silicon-switched C/Si—H group. Therefore, sila-ibuprofen is more water soluble and has a lower melting enthalpy. However, its binding and inhibition properties of cyclooxygenases appear to be very similar to regular ibuprofen. Therefore, in this study, intermolecular interactions and interaction densities of both ibuprofen and sila-ibuprofen in their biologically active forms, i.e. deprotonated and as the pure S-enantiomers are investigated. Quantum-crystallographically refined salts with argininium and 1-phenyl­ethan-1-amoninium (PEA) counter-cations as crystalline models of the interactions with the guanidine functional group of arginine inside cyclooxygenases are presented. The similarities and differences between the polarization of ibuprofen and sila-ibuprofen in the crystal, enzyme, solvent and isolated environments are discussed based on quantum-chemical calculations. For the explicit crystal and enzyme environments, specifically, molecular dynamics simulations starting from the crystal models were combined with QM/MM calculations.

The diffusion behavior of Mg2+ in electrolytes is not as readily accessible as that from Li+ or Na+ utilizing PFG NMR, due to the low sensitivity, poor resolution, and rapid relaxation encountered when attempting 25Mg NMR. In MgTFSI2/DME solutions, "bound" DME (coordinating to Mg2+) and "free" DME (bulk) are distinguishable from 1H NMR. With the exchange rates between them obtained from 2D 1H EXSY NMR, we can extract the self-diffusivities of free DME and bound DME (which are equal to that of Mg2+) before the exchange occurs using PFG diffusion NMR measurements coupled with analytical formulas describing diffusion under two-site exchange. The high activation enthalpy for exhange (65-70 kJ/mol) can be explained by the structural change of bound DME as evidenced by its reduced C-H bond length. Comparison of the diffusion behaviors of Mg2+, TFSI-, DME, and Li+ reveals a relative restriction to Mg2+ diffusion that is caused by the long-range interaction between Mg2+ and solvent molecules, especially those with suppressed motions at high concentrations and low temperatures.

In this investigation, mechanical grinding was applied to fabricating the Mg-based alloys La7Sm3Mg80Ni10 + 5 wt.% M (M = None, TiO2, La2O3) (named La7Sm3Mg80Ni10–5 M (M = None, TiO2, La2O3)). The result reveals that the structures of as-milled alloys consist of amorphous and nanocrystalline. The particle sizes of the added M (M = TiO2, La2O3) alloys obviously diminish in comparison with the M = None specimen, suggesting that the catalysts TiO2 and La2O3 can enhance the grinding efficiency. What's more, the additives TiO2 and La2O3 observably improve the activation performance and reaction kinetics of the composite. The time required by releasing 3 wt.% hydrogen at 553, 573 and 593 K is 988, 553 and 419 s for the M= None sample, and 578, 352 and 286 s for the M = TiO2 composite, and 594, 366, 301 s for the La2O3 containing alloy, respectively. The absolute value of hydrogenation enthalpy change |ΔH| of the M (M = None, TiO2, La2O3) alloys is 77.13, 74.28 and 75.28 kJ/mol. Furthermore, the addition of catalysts reduces the hydrogen desorption activation energy ( E a de ).

Mg-based materials are one of the most promising hydrogen storage candidates due to their high hydrogen storage capacity, environmental benignity, and high Clarke number characteristics. However, the limited thermodynamics and kinetic properties pose major challenges for their engineering applications. Herein, we review the recent progress in improving their thermodynamics and kinetics, with an emphasis on the models and the influence of various parameters in the calculated models. Subsequently, the impact of alloying, composite, and nano-crystallization on both thermodynamics and dynamics are discussed in detail. In particular, the correlation between various modification strategies and the hydrogen capacity, dehydrogenation enthalpy and temperature, hydriding/dehydriding rates are summarized. In addition, the mechanism of hydrogen storage processes of Mg-based materials is discussed from the aspect of classical kinetic theories and microscope hydrogen transferring behavior. This review concludes with an outlook on the remaining challenge issues and prospects.

Very Low-Pressure Plasma Spraying (VLPPS) is an emerging process allowing the manufacturing of metallic or ceramic coatings under reduced pressure conditions (i.e., in the 150 Pa range). It aims at vaporizing primary feedstock precursors in the warm core of the plasma flow and at carrying them, through the expanded plasma column, towards the surface to be coated, where they condense to form a deposit. This process also can be operated in a reactive mode. In such a case, a secondary reactive gaseous precursor is injected in the plasma flow where it can react with the primary vaporized precursors. In this work, nitrogen is considered as the secondary gaseous precursor. Thereby, nitriding reactions occur between this secondary precursor and the primary one, titanium in the considered case. Optical emission spectroscopy is implemented to identify the reactive nitrogen species in an Ar-H2-N2 plasma gas ternary mixture together with the reaction mechanisms giving rise to the nitriding processes. Two mechanisms have been identified. At first, a gas-gas reactions occur between titanium vapors and N2, N2+ and N species leading to the formation of TiN nitrides; At second, a solid-gas reactions occur between flattened titanium lamellae and N2 species, leading to the formation of Ti2N nitrides, which as evidenced by XRD analyses. Nevertheless, the number of nitrides is rather low, very likely due to the limited fraction of titanium vapors in the system: this is a consequence of a rather limited plasma energy (i.e., net power of about 26 kW, corresponding to an average plasma mass enthalpy of 15.21 kJ kg−1).

In this study, we investigate the reaction mechanisms of precursor adsorption during the atomic layer deposition (ALD) using density functional theory (DFT) calculations and ideal-gas methods; herein, we considered adsorption of tris(dimethylamino)silane (TDMAS) on a hydroxylated SiO2 surface to be the example for our investigation. When the reaction free energy is calculated, the DFT results obtained at 0 K suggest that the dissociation of a hydrogen atom from TDMAS is favorable upon TDMAS adsorption, which is inconsistent with the experimental results where one dimethylamino group is released. The experimental results can be accurately predicted when enthalpy and entropy changes are considered at elevated temperatures, thereby indicating the significance of finite-temperature effects in free-energy changes for solid-gas reactions. We analyze the changes in enthalpy and entropy and find that dimethylamine is a more favorable gaseous product than H2 owing to its larger translational and rotational entropy.

The addition of ferric ferrocyanide (Prussian blue; PB) to adsorbents could enhance the adsorption performance of 133Cs. Toward this goal, we present a heterogeneously integrated carbonaceous material platform consisting of PB in direct contact with CO2-activated carbon filters (PB-CACF). The resulted sample retains 24.39% more PB than vice versa probed by the ultraviolet–visible spectrometer. We leverage this effect to capture 133Cs in the aqueous environment via the increase in ionic strength and micropores. We note that the amount of PB was likely to be the key factor for 133Cs adsorption compared with specific surface characteristics. The revealed adsorption capacity of PB-CACF was 21.69% higher than the bare support. The adsorption characteristics were feasible and spontaneous. Positive values of ΔHo and ΔSo show the endothermic nature and increased randomness. Based on the concept of capturing hazardous materials via hazardous materials, our work will be of interest within the relevant academia for collecting radionuclides in a sufficient manner.

Heavy metal ion is one of the major environmental pollutants. In this study, a Cu(II) ions imprinted magnetic chitosan beads are prepared to use chitosan as functional monomer, Cu(II) ions as template, Fe3O4 as magnetic core and epichlorohydrin and glutaraldehyde as crosslinker, which can be used for removal Cu(II) ions from wastewater. The kinetic study shows that the adsorption process follows the pseudo-second-order kinetic equations. The adsorption isotherm study shows that the Langmuir isotherm equation best fits for the monolayer adsorption processes. The selective adsorption properties are performed in Cu(II)/Zn(II), Cu(II)/Ni(II), and Cu(II)/Co(II) binary systems. The results shows that the IIMCD has a high selectivity for Cu(II) ions in binary systems. The mechanism of IIMCD recognition Cu(II) ions is also discussed. The results show that the IIMCD adsorption Cu(II) ions is an enthalpy controlled process. The absolute value of ΔH (Cu(II)) and ΔS(Cu(II)) is greater than ΔH (Zn(II), Ni(II), Co(II)) and ΔS (Zn(II), Ni(II), Co(II)), respectively, this indicates that the Cu(II) ions have a good spatial matching with imprinted holes on IIMCD. The FTIR and XPS also demonstrates the strongly combination of function groups on imprinted holes in the suitable space position. Finally, the IIMCD can be regenerated and reused for 10 times without a significantly decreasing in adsorption capacity. This information can be used for further application in the selective removal of Cu(II) ions from industrial wastewater.