Insights into the adsorption performance and mechanism of Cr(Ⅵ)onto porous nanocomposite prepared from gossans and modified coal interface:Steric,energetic,and thermodynamic parameters interpretations

Herein,iron oxide/hydroxides deposits(gossans)were utilized,for the first time,in the fabrication of magnetite nanoparticles(MNPs)to load modified coal(MC).The as-synthesized MNPs@MC composite was characterized via different techniques and utilized for the Cr(Ⅵ)remediation.Experimental studies supported by theoretical treatment were applied to offer a new overview of the Cr(Ⅵ)adsorption geometry and mechanism at 25-45℃.Experimental results suggested that the Cr(Ⅵ)uptake was mainly governed by adsorption-reduction coupled mechanism.The Langmuir model fitted well the Cr(Ⅵ)adsorption data with maximum adsorption capacities extended from 115.24 to 129.63 mg·g^(-1).Theoretical calculations indicated that Cr(Ⅵ)ions were adsorbed on the MNPs@MC following the theory of the advanced monolayer statistical model.The number of ions removed per site ranged from 1.88 to1.23 suggesting the involvement of vertical geometry and multi-ionic mechanism at all temperatures.The increment of the active sites density and the adsorption capacity at saturation with improving temperature reflected an endothermic process.Energetically,the Cr(Ⅵ)adsorption was controlled by physical forces as the adsorption energies were less than 40 kJ·mol^(-1).The calculated free enthalpy,entropy.and internal energy explained the spontaneous nature and the viability of Cr(Ⅵ)adsorption on the MNPs@MC adsorbent.These results offer a new approach in utilizing the iron-rich deposits as gossans in the preparation of magnetic and low-cost adsorbents for wastewater remediation.

Guide and control of thermal conduction with isotropic thermodynamic parameters based on a rotary-concentrating device

A rotary-concentrating device for thermal conduction is constructed to control and guide thermal energy transmitting in elastic plates.The designed device has the ability of concentrating for thermal conduction and controlling the processes of thermal diffusion in a plate.The multilayered isotropic material properties of the rotary-concentrating device are derived based on the transformation and rotary medium method and a rotation parameter to control the thermal diffusion process is introduced.The efficiency of the rotary-concentrating device for thermal conduction is verified.Stability of temperature fields in a plate with the rotary-concentrating device is analyzed to study the performance of rotary-concentrating.Numerical examples show that the constructed rotary-concentrating device for thermal conduction can effectively rotate and focus on the thermal energy into the device for a wide range of diffusion temperatures,which can enhance the thermal conduction.Therefore,this study can provide a theoretical support for potential applications in fields of energy harvesting and thermal conduction control.

Effect of thermodynamic parameters on prediction of phase behavior and process design of extractive distillation

Extractive distillation was investigated for separation of the minimum azeotrope of n-propanol/water, via the Aspen Plus simulation platform. Experimental data of n-propanol/water, which could pass the thermodynamic consistency test, were regressed to get suitable binary interaction parameters(BIPs) by the UNIQUAC thermodynamic model. The azeotrope system was heterogeneous in the simulation with built-in BIPs, which was contrary to the experimental data. The study focused on the effect of thermodynamic parameters on the prediction of phase behavior, and process design of extractive distillation. N-methyl-2-pyrrolidone(NMP) and ethylene glycol were used as solvents to implement the separation. Processes with built-in and regressed BIPs were explored,based on the minimum total annual cost(TAC). There were significant differences in the phase behavior simulation using different thermodynamic parameters, which showed the importance of BIPs in the design and optimization of extractive distillation.

Thermodynamic properties and mixing thermodynamic parameters of two-phase metallic melts

Based on the calculating model of metallic melts involving eutectic, the calculating equations of mixing thermodynamic parameters for two phase metallic melts have been formulated in the light of those equations of homogeneous solutions. Irrespective as to whether the activity deviation relative to Raoultian behavior is positive or negative, or the deviation is symmetrical or unsym-metrical, the evaluated results not only agree well with experimental values, but also strictly obey the mass action law. This testifies that these equations can authentically reflect the structural reality and mixing thermodynamic characteristics of two-phase metallic melts. The calculating equations of mixing thermodynamic parameters for the model of two phase metallic melts offer two practical criteria (activity and mixing thermodynamic parameters) and one theoretical criterion (the mass action law).

Calculation of Thermodynamic Parameters for Freundlichand Temkin Isotherm Models

Derivation of the Freundlich and Temkin isotherm models from the kinetic adsorption/desorpt ion equations was carried out to calculate their thermodynamic equilibrium constants. The calculation formulae ofthree thermodynamic parameters, the standard molar Gibbs free energy change, the standard molar enthalpy change and the standard molar entropy change, of isothermal adsorption processes for Freundlich andTemkin isotherm models were deduced according to the relationship between the thermodynamic equilibriumconstats and the temperature.

Calculation of Thermodynamic Parameters of Mg-Al-Y Alloy

By means of Miedema formation enthalpy model with Toop model, the excess free-energy, enthalpies of formation, excess entropies and activity values of all components of Mg-A1-Y ternary alloy were calculated with computer programming. The experimental results show that enthalpies of formation, excess free- energy and excess entropies of the ternary alloy are negative in the whole content range, the minimum values at 1 123 K are all obtained at x_Al=55%, x_y=45%, X_Mg=0%, which are -37.969, -30.961 kJ/mol and -6.24 J/（mol-k） respectively. Activity curves show that the activity values of A1 and Y in Mg-A1-Y ternary alloy rapidly decrease with the decrease of molar fraction, the values of which are very small when the molar fraction decreases to 0.4. It means that there is a strong interaction between A1 and Y and stable compounds can be form in the Mg-A1-Y ternary alloy system.

Kinetics and Thermodynamic Parameters of the CopperExchange on Na-montmorillonite Clay Mineral inSelected Solvents

The kinetics of Cu ion exchange on Na-montmorillonite clay mineral has been investigated at three temperatures, in three solvents: H2O, ethylene glycol and glycerol. Solvent effects on the reaction rate have been discussed. The thermodynamic activation parameters were calculated and discussed in terms of solvation effects. The determined isokinetic temperature indicates that the reaction is enthalpy controlled where the interaction between solvent and clay surface plays an important role. A reaction mechanism which describes the solvent effect on the rate of Cu ion exchange is proposed.

Sol-Gel γ-Al2O3 Nanoparticles Assessment of the Removal of Eosin Yellow Using: Adsorption, Kinetic and Thermodynamic Parameters

The adsorption behavior of eosin yellow (EY) from aqueous solution onto γ-Al2O3 nanoparticles in batch technique was studied. γ-Al2O3 NPs was prepared and characterized by SEM, TEM, XRD and FTIR analysis. The effect of pH, dosage of adsorbent, contact time, temperature, and the initial concentration of dye was investigated. The maximum amount of dye removal found about 99.36% at pH4, the adsorption dose 1g/L, with the initial dye concentration of 100 mg/L, and the temperature of 25°C, with contact time 120 min. The adsorption behavior of the eosin yellow dye is applicable to Langmuir isotherm model, with the maximum sorption capacity of 47.78 mg/g of γ-Al2O3. The kinetic data also described by the pseudo-second-order model with a correlation coefficient (0.9999), and the mechanism of the process showed a multi-linear steps and the intra-particle diffusion was not only rate controlling step. The adsorption process was endothermic with positive enthalpy of 121.8 kJ/mol, and showed spontaneous process with a mean free energy -5.19 kJ/mol, and increase randomness, 369.77 J/mol. k, at the adsorbent solution interface. The adsorption process was chemisorption in nature The activation energy estimated from Arrhenius and modified Arrhenius is 40.9 kJ/mol, 106.37 kJ/mol respectively. The sticking probability of EY onto Al2O3 NPs very high estimated from the value of S* < 1, (4.82E-19).

Thermodynamic properties and mixing thermodynamic parameters of binary homogeneous metallic melts

After the investigation on the thermodynamic properties and mixingthermodynamic parameters of binary homogeneous metallic melts involving compound, peritectic as wellas solid solution, it was found that the equations of mixing free energy DELTA G^m and excess freeenergy DELTA G^(XS) of them can he expressed by the following equations: DELTA G^m = SIGMA x [SIGMAN_i DELTA G_I^(THETA) + RT(SIGMA N_j ln N_j + SIGMA N_i ln N_i )] and DELTA G^(XS) = DELTA G^m -RT(a ln a + b ln b), respectively.

Relationship between Thermodynamic Parameters for Mn-Fe Melt and Temperature

The carbon solubility in Mn-Fe melts were measured at 1350℃,1375℃,1425℃and 1450 ℃,and accordingly the calculated equations were obtained.By thermodynamic derivation and calculation,some relationships between thermodynamic parameters for Mn-Fe melt and temperature were obtained.

THERMODYNAMIC PARAMETERS IN THE NUCLEATION OF LIQUID IRON

By using of electrolytic pure iron, the specimens containing different oxide content were made in a Mo wire furnace. The DTA method was employed to measure the undercooling of liquid iron during solidification. The relations between the cleanness of liquid iron and undercooling, thermodynamic driving force of nucleation, the nucleus forming energy, as well as the critical radius of nucleus have been investigated. The results showed that with the increase of cleanness of liquid iron the undercooling and thermodynamic driving force increased, while the nucleus forming energy and critical radius of nucleus decreased.

Investigation of kinetic and thermodynamic parameters of coal pyrolysis with model-free fitting methods

Kinetic analyses are important means for understanding the complicated coal pyrolysis process.This work conducted non-isothermal pyrolysis of four low-medium rank coals with thermogravimetric analyzer at different heating rates(5,10 and 20 K/min).Four model-free fitting approaches including KAS,OFW,Starink and Friedman methods were used to analyze pyrolysis kinetics of the coals.Thermodynamic parameters including enthalpy(ΔH)Gibbs free energy(ΔG)and entropy(ΔS)were calculated with the activation values(E)obtained with KAS method.For the kinetic analysis,the KAS,OFW and Starink methods give close E values over the whole conversion range,but the Friedman method shows more deviant results.The thermodynamic favorability of coal pyrolysis is discussed,bothΔH andΔG increase with conversion consistently with the variation of E,revealing that pyrolysis is endothermic and thermodynamic favorability is reduced with conversion rises.The minusΔS implies that coal structures evolve from disordered to organized ones as universally accepted.These results are expected to deepen our understanding and to optimize the conditions of coal pyrolysis.

Crystallization thermodynamics of 2,4(5)-dinitroimidazole in binary solvents

2,4(5)-Dinitroimidazole(2,4(5)-DNI)is an important organic intermediate,and itself can also be used for energetic material.In this work,the solubility of 2,4(5)-DNI in(methanol+water,acetonitrile+water,acetone+water)binary solvents were measured by using a dynamic test method from 278.15 K to 323.15 K under 101.1 k Pa.The Jouyban–Acree model,van't Hoff–Jouyban–Acree model,Apelblat–Jouyb an–Acree model,Ma model,and Sun model were used to correlate the experimental data.The values of relative average deviation(RAD)and root-mean-square deviation(RMSD)were very small,indicating that the error between the experimental value and the correlated value was very small.The thermodynamic parameters such as dissolution enthalpy,dissolution entropy and Gibbs energy were calculated based on solubility data.High-purity of 2,4(5)-DNI was efficiently obtained by using cooling and dilution crystallization method.

Thermodynamic parameters of interaction of HC1 with alcohols in water Ⅲ.HCl-ethanol-water system at 278.15-318.15 K

Pt,H2(g,p0)HCl(mE)|AgCl-AgPt, H2(g, p0)|HCl(mE), EtOH(mN)|AgCl-Ag have been measured at 10 degree intervals from 278.15 to 318.15 K, where EtOH refers to ethanol, mE=0.005-0.1 mol.kg-1, mN=0.4-1.0 mol.kg-1. The salting constant kS of EtOH by HCl and the thermodynamic parameters of interaction, fEN(gEN> hEN, sEN] cP,EN)> of EtOH with HCI in water have been evaluated. It has been shown that kS>0, gEN>0,hEN>0, SEN>0 ,and cp,EN<0.The signs of these parameters and the temperature dependence of them have been discussed on the basis of structural interaction and the group additivity models.

Effects of thermodynamics parameters on mass transfer of volatile pollutants at air-water interface

A transient three-dimensional coupling model based on the compressible volume of fluid （VOF） method was developed to simulate the transport of volatile pollutants at the air-water interface. VOF is a numerical technique for locating and tracking the free surface of water flow. The relationships between Henry＇s constant, thermodynamics parameters, and the enlarged topological index were proposed for nonstandard conditions. A series of experiments and numerical simulations were performed to study the transport of benzene and carbinol. The simulation results agreed with the experimental results. Temperature had no effect on mass transfer of pollutants with low transfer free energy and high Henry＇s constant. The temporal and spatial distribution of pollutants with high transfer free energy and low Henry＇s constant was affected by temperature. The total enthalpy and total transfer free energy increased significantly with temperature, with significant fluctuations at low temperatures. The total enthalpy and total transfer free energy increased steadily without fluctuation at high temperatures.

Numerical computation algorithm of explosion equations and thermodynamics parameters of mine explosives

A new numerical algorithm is presented to simulate the explosion reaction process of mine explosives based on the equation of state, the equation of mass conservation and thermodynamics balance equation of explosion products. With the affection of reversible reaction of explosion products to explosion reaction equations and thermodynamics parameters considered, the computer program has been developed. The computation values show that computer simulation results are identical with the testing ones.

Comprehensive insights into recent innovations:Magnesium-inclusive high-entropy alloys

This review focuses on thermodynamic and physical parameters,synthesis methods,and reported phases of Magnesium(Mg)containing high-entropy alloys(HEAs).Statistical data of publications concerning Mg-containing HEAs were collected and analyzed.Data on the chemical elements included in Mg-containing HEAs,their theoretical end experimental densities,thermodynamic parameters,physical parameters,fabricated techniques and reported phases were also collected and discussed.On the basis of this information,a new classification for HEAs was proposed.It is also shown that the existing thermodynamic parameters cannot accurately predict the formation of a single phase solid solution for Mg-containing HEAs.The physical parameters of Mg-containing HEAs are within a wide range,and most of the synthesized Mg-containing HEAs have a complex multiphase structure.

Thermodynamic Properties for Polybrominated Dibenzothiophenes by Density Functional Theory

The thermodynamic properties of 135 polybrominated dibenzothiophenes （PBDTs） in the gaseous state at 298.15 K and 1.013×10^5 Pa, are calculated using the density functional theory （the B3LYP/6-311G^＊＊） with Gaussian 03. Based on these data, the isodesmic reacflons are designed to calculate the standard enthalpy of formation （△fH^θ） and the standard Gibbs energy of formation （△fG^θ） of PBDTs. The relations of these thermodynamic parameters with the number and positionof bromine subsfituents （NPBS） are discussed, and it is found that there exist good correlations between othermody namic parameters （including heat capacity at constant volume, entropy, enthaipy, free energy, △fH^θ, △fG^θ） and NPBS. Thoe relative stability order of PBDT congeners is proposed theoretically based on the relative magnitude of their △fG^θ. In addition, the values of molar heat capacities at constant pressure （Cp,m） for PBDT c ongelaers are calculated.

Effect of different additives on the phase separation behavior and thermodynamics of p-tert-alkylphenoxy poly (oxyethylene) ether in absence and presence of drug

Cloud point （CP） determinations of 4-（1,1,3,3-tetramethylbutyl）phenyl-polyethylene glycol （TX-100 （nonionic surfactant）） was carried out in aqueous as well as in the attendance of drug （ceftriaxone sodium trihydrate （CFT））/（CFT ＋ different inorganic salts） and discussed thoroughly. Nonionic surfactants are employed exten- sively in different formulations. In aqueous solution, the values of CP of TX-100 are obtained to increase by means of enhancing of their concentration in the solution. The CP values of TX-100 solutions were found to de- crease in the presence of drug and their values decrease more with rising concentrations of the drug. The values of CP of CFT and TX-100 mixtures were found to further decrease in the attendance of inorganic salts in compar- ison to their absence. The effect of different sodium salts in decreasing CP values of TX-100 was achieved in the following order： NaCO3 〉 Na2SO4 〉 NaCl. However, in the case of potassium and ammonium salts, the decreasing order obtained is K2SO4 〉 KCO3 〉 KCI and （NH4）2SO4 〉 Na2CO3 〉 NH4Cl respectively. Various thermodynamic pa- rameters for example standard free energy （△G c）, standard enthalpy （△H c） as well as standard entropy （△S c） changes of phase separation were also evaluated and discussed in detail on the basis of their behavior.

Crystallization thermodynamics of 2,4(5)-dinitroimidazole in eleven pure solvents

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%.