Determination of Equilibrium Distribution Coefficients of Impurities in Phosphorus by Vertical Zone-melting Technique

The equilibrium distribution coefficients of 12 impurities （As,Fe,Ca,Co,Al,Cr,Cu,Mg,Mn,Ni,Pb,Zn） in phosphorus were obtained by measuring their effective distribution coefficients at zone travel rate of 3,5,10,15,and 20 mm·h-1 in the purification process with vertical zone-melting technique.The results indicate that the method is reliable.The equilibrium distribution coefficients are below 0.3 except arsenic.

Critical anomaly and finite size scaling of the self-diffusion coefficient for Lennard Jones fluids by non-equilibrium molecular dynamic simulation

We use non-equilibrium molecular dynamics simulations to calculate the self-diffusion coefficient, D, of a Lennard Jones fluid over a wide density and temperature range. The change in self-diffusion coefficient with temperature decreases by increasing density. For density ρ＊ = ρσ3 = 0.84 we observe a peak at the value of the self-diffusion coefficient and the critical temperature T＊ = kT/ε = 1.25. The value of the self-diffusion coefficient strongly depends on system size. The data of the self-diffusion coefficient are fitted to a simple analytic relation based on hydrodynamic arguments. This correction scales as N-α, where α is an adjustable parameter and N is the number of particles. It is observed that the values of a 〈 1 provide quite a good correction to the simulation data. The system size dependence is very strong for lower densities, but it is not as strong for higher densities. The self-diffusion coefficient calculated with non-equilibrium molecular dynamic simulations at different temperatures and densities is in good agreement with other calculations fronl the literature.

Activity Coefficient Models to Describe Vapor-Liquid Equilibrium in Ternary Hydro-Alcoholic Solutions

In this study,three semipredictive activity coefficient models:Wilson,non-random-two liquid model(NRTL),and universal quasi-chemical model(UNIQUAC),have been used for modeling vapor-liquid equilibrium properties of ternary mixtures that include substances found in alcoholic distillation processes of wine and musts.In particular,vapor-liquid equilibrium in ternary mixtures containing water + ethanol + congener has been modeled using parameters obtained from binary and ternary mixture data.The congeners are substances that although present in very low concentrations,of the order of part per million,are important enological parameters.The results given by these different models have been compared with literature data and conclusions about the accuracy of the models studied are drawn,recommending the best models for correlating and predicting phase equilibrium properties of this type of mixtures.

The Equilibrium Coefficient Kp and Petroleum Exploration:Design of the New Generation of Petroleum Exploration Instrument

The main reason why the application of nuclear technology in petroleum exploration has not yet been accepted by most exploration workers is that they are not clear about the homologous distribution features of oil and gas fields and radioactive radiation. The authors hold that the disequilibrium of uranium, radium and radon as a natural radioactive series is the basic feature in the use of this technology in petroleum exploration. The invention Gamma-ray Spectral Measurement of the Equilibium Coefficient Kp and Its Embodiment of the senior author now can readily solve that problem and replace the impedient measure of normalization of uranium and potassium to thorium that had to be proposed before. Application of this impedient measure has some limitations. In areas where the surface is covered by beach or river sands, thorium minerals such as monazite may be concentrated by placering. This could result in local thorium highs that would yield local uranium and potassium lows after normalization to thorium, and these would constitute false anomalies.

SELF-INTERACTION COEFFICIENTS OF Ca AND Mg IN DILUTE Sn-BASED SOLUTION

The interaction coefficients of Ca.Ti and Mg in the dilute Sn-based solution have been de- termined at 1500℃.Experimental measurements were taken by equilibrating the slag-alloy systems with metallic Sn as flux and graphite as reducing agent under Ar atmosphere mixed with different portion of CO.It was found that a considerable error may produce if the coefficients of ε_(Ca)^(Ca),ε_(Mg)^(Mg)and ε_(Ti)^(Ti)in the molten Sn were neglected when the activities of the components CaO,MgO and TiO_2 in the slags were estimated by this method.

Activity coefficient of NiO in SiO_(2)-saturated MnO–SiO_(2)slag and Al_(2)O_(3)-saturated MnO–SiO_(2)–Al_(2)O_(3)slag at 1623 K

As a part of the fundamental study related to the reduction smelting of spent lithium-ion batteries and ocean polymetallic nodules based on MnO–SiO_(2)slags,this work investigated the activity coefficient of NiO in SiO_(2)-saturated Mn O–Si O_(2)slag and Al_(2)O_(3)-saturated Mn O–SiO_(2)–Al_(2)O_(3)slag at 1623 K with controlled oxygen partial pressure levels of 10^(-7),10^(-6),and 10^(-5)Pa.Results showed that the solubility of nickel oxide in the slags increased with increasing oxygen partial pressure.The nickel in the Mn O–Si O_(2)slag and Mn O–Si O_(2)–Al_(2)O_(3)slag existed as Ni O under experimental conditions.The addition of Al_(2)O_(3)in the Mn O–Si O_(2)slag decreased the dissolution of nickel in the slag and increased the activity coefficient of Ni O.Furthermore,the activity coefficient of Ni O(γN_(i O)),which is solid Ni O,in the Si O_(2)saturated Mn O–Si O_(2)slag and Al_(2)O_(3)saturated Mn O–Si O_(2)–Al_(2)O_(3)slag at 1623 K can be respectively calculated asγN_(i O)=8.58w(Ni O)+3.18 andγN_(i O)=11.06w(Ni O)+4.07,respectively,where w(Ni O)is the Ni O mass fraction in the slag.

Vapor-Liquid Equilibrium Data of Carbon Dioxide＋Methyl Propionate and Carbon Dioxide＋Propyl Propionate Systems

High-pressure vapor-liquid equilibrium data for the binary systems of methyl propionate＋carbon dioxide and propyl propionate＋carbon dioxide were measured at pressure from 1.00 MPa to 12.00 MPa and temperature in the range from 313 K to 373 K. Experimental results were correlated with the Peng-Robinson equation of state with the two-parameter van der Waals mixing rule. At the same time, the Henry＇s coefficient, partial molar enthalpy change and partial molar entropy change of CO2 during dissolution at different temperature were also calculated.

Vapor-Liquid Equilibrium Measurements and Modeling for Ternary System Water ＋ Ethanol ＋ 1-Butyl-3-methylimidazolium Acetate

Vapor-liquid equilibrium(VLE) data were measured for ternary system water + ethanol + 1-butyl-3methylimidazolium acetate([bmim][OAc]),in a relatively wide range of ionic liquid(IL) mass fractions up to 0.8.Six sets of complete T-x-y data were obtained,in which the mole fraction of ethanol on IL-free basis was fixed separately at 0.1,0.2,0.4,0.6,0.8,and approximate 0.98.The non-random-two-liquid(NRTL) and electrolyte non-random-two-liquid(eNRTL) equations were used for correlation,showing similar deviations.The ternary VLE was also modeled with the correlation from two data sets,with the mole fractions of ethanol on IL-free basis being 0.1 and approximate 0.98.The VLE data were also reproduced satisfactorily.With the eNRTL model,the root-mean-square deviation for temperature is 0.79 K and that for vapor-phase mole fraction is 0.0094.The calculations are in good agreement with experimental data.The effect of the IL on the VLE behavior of the volatile components is also illustrated.

Partition Equilibrium on the Interface Between a Charged Membrane and a Mixed Electrolyte Aqueous Solution

Ionic partition equilibrium on a charged membrane immersed in a mixed electrolyte solution was systematically investigated and several models were established for the determination of partition coefficients. On the basis of theoretical models, the effects of the concentration ratio λ of the fixed group(charged density) to reference electrolyte, the concentration ratio η between the two electrolytes existing in the solution and the valence of the electrolyte ions on the partition equilibrium in a positively charged membrane were analyzed and simulated within the chosen parameters in detail. The obtainable results can also be applicable to a sytem of mixed electrolytes contacting with a negatively charged membrane. The theoretical calculations were confirmed with the experimental data of model mixed electrolytes, NaCl+HCl and CaCl 2+NaCl partitioned in the system of self made negatively charged membrane sulphonated poly(phenylene oxide)(SPPO) with different charge densities.

Prediction of Vapor-Liquid Equilibrium Data from C—H Band Shift of IR Spectra in Some Binary Systems

Prediction of vapor-liquid equilibrium （VLE） is extremely necessary to separate liquid mixture in chemical production, especially when the required experimental data are difficult to measure, or the measurement is not economical. The infinite dilution activities can be used to predict VLE. However, it needs both the ends of the activities that are difficult to obtain for many systems. In the present study, a new model is proposed for correlating the frequency shift of C-H stretching band of IR spectra over the whole concentration. Investigated mixtures in- clude water/2-propanol, water/N, N-dimethylformamide （DMF）, water/methanol, water/ethanol, water/1, 4-dioxane, and water/dimethylsulfoxide （DMSO） systems. Simultaneous correlations of C--H frequency shift and VLE data are made. Furthermore, the VLE data were predicted with satisfactory results by the parameters obtained from IR spectra coupled with one ot the intinite chlution activity coefficients.

Partition Equilibrium Between Charged Membrane and Single Electrolyte Aqueous Solution

Ionic partition equilibrium in charged membrane immersed in solution of single electrolyte with monovalence or multi-valence is systematically investigated and several expressions are established for determination of partition coefficients. On this basis, the effects of the ratio of membrane charge density to bulk electrolyte solution concentration, the charge sign and valence of electrolyte ions and the type of membrane on the partition equilibrium were analyzed and simulated within chosen parameters. It is revealed that ion partition is not related solely with the respective concentrations but also definitely with the concentration ratio of fixed group to bulk solution in addition to the charge sign and the valence. For a counterion, the partition coefficient increases with this ratio and the valence; while for a coion, the partition coefficient decreases with this ratio and the valence. The theoretical calculations were compared with the experimental data and a good agreement was observed.

Salt Effect on the Liquid-Liquid Equilibrium of （Water ＋ Propionic Acid ＋ Cyclohexanol） System at T=（298.2,303.2,and 308.2） K

Effects of salt and temperature on the liquid phase equilibrium of the(water + propionic acid + cyclohexanol) system were investigated.The liquid-liquid equilibrium data in the presence of KCl for various salt ionic strength of 0.5,1.0,1.5,2.0,and 2.5 mol·dm3 and in absence of the salt at T=(298.2,303.2,and 308.2)K were determined.The experimental results were correlated based on the Othmer-Tobias equation and Pitzer ion-interaction model.Thermodynamic properties such as distribution coefficients and activity coefficients of propionic acid in water + cyclohexanol were determined.In addition,the separation factor,S,of the chosen solvent was obtained for the investigated system.

Isobaric Vapor-Liquid Equilibrium for Toluene, 3-Methylthiophene and N-formylmorpholine at 101.33 kPa

Isobaric vapor-liquid equilibrium (VLE) data were measured for binary mixtures of toluene+N- formylmorpholine, toluene+3-methylthiophene and 3-methylthiophene+N-formylmorpholine at 101.33 kPa. The VLE data of the binary systems were found to be thermodynamically consistent. The saturated vapor pressure calculated by CSGC-PR equation of the pure component had higher accuracy than that calculated by Antoine equation. The liquid- phase activity coefficients of the binary systems were calculated by the Wilson, NRTL and UNIFAC models, and the binary interaction parameters of the three models were determined by the VLE data. The Wilson model was selected as the most suitable model to predict the VLE data of the ternary system of toluene+3-methylthiophene+N- formylmorpholine. The relative volatility between toluene and 3-methylthiophene was also calculated. Moreover, the effect of N-formylmorpholine as solvent was studied. When the molar ratio of solvent to feed (S/F) was 7, the relative volatility reached 1.904, which is almost twice the relative volatility without solvent. Therefore, N-formylmorpholine can be considered as an effective extracting agent for the separation of the close-boiling mixture of toluene+3- methylthiophene by extractive distillation.

Modified DIX model for ion-exchange equilibrium of L-phenylalanine on a strong cation-exchange resin

L-phenylalanine, one of the nine essential amino acids for the human body, is extensively used as an ingredient in food, pharmaceutical and nutrition industries. A suitable equilibrium model is required for purification of L-phenylalanine based on ion-exchange chromatography. In this work, the equilibrium uptake of L-phenylalanine on a strong acid-cation exchanger SH11 was investigated experimentally and theoretically. A modified Donnan ion-exchange （DIX） model, which takes the activiW into account, was established to predict the uptake of L-phenylalanine at various solution pH values. The model parameters including selectivity and mean activity coefficient in the resin phase are presented. The modified DIX model is in good agreement with the experimental data. The optimum operating pH value of 2.0, with the highest t-phenylalanine uptake on the resin, is predicted by the model. This basic information combined with the general mass transfer model will lay the foundation for the prediction of dynamic behavior of fixed bed separation process.

EQUILIBRIUM OF Mg-S IN Ni MELTS

The equilibrium of Mg-S in Ni melt was studied by the method of vapour equilibrium in a sealed chamber.At 1530℃ the equilibrium constant of the reaction MgS_(s)=Mg_(Ni)+S_(Ni)and the activity interaction coefficient were determined as K_(MgS)=6.76×10^(-5)and e_S^(Mg)=-9.1.

Measurement and Modeling of Vapor-Liquid Equilibrium for Ternary System Water+2-Propanol+1-Butyl-3-methylimidazolium Chloride

Vapor-liquid equilibrium(VLE)data for water+2-propanol+1-butyl-3-methylimidazolium chloride([bmim]Cl)were measured.Six sets of complete T,x,y data are reported,in which the 2-propanol mole fraction on IL-free basis is fixed separately at 0.1,0.2,0.4,0.6,0.8,and approximate 0.98,while the IL mass fraction is varied from 0.1 to 0.8,in an interval of 0.1.The non-random-two-liquid(NRTL)and electrolyte non-random-two-liquid(eNRTL)equations are used to correlate the experimental data with satisfactory results.The ternary VLE behavior is also modeled with the parameters obtained by correlating two data sets,in which the mole fraction of 2-propanol on IL-free basis is approximately 0.1 and 0.98.In this way,the six sets of data are reproduced satisfactorily.With the eNRTL model,the root-mean-square deviation for temperature is 0.82 K and that for vapor-phase mole fraction is 0.0078.The influences of IL on activity coefficients and relative volatility of the volatile components are also graphically illustrated.

Henry’s Equilibrium Partitioning between Ground Water and Soil Air: Predictions versus Observations

Humans spend 64% - 94% of their time indoors;therefore, indoor air quality is very important for potential exposure to volatile organic compounds (VOC). The source of VOC in the subsurface may come from accidental or intentional releases, leaking landfills or leaking underground and above-ground storage tanks. Once these contaminants are present near or beneath buildings, they may move as a vapour through soil gas and enter the building. A large number of vapour intrusion (VI) algorithms have been published in peer-reviewed publications that link indoor VOC concentrations to the contamination of soils. These models typically include phase partitioning calculations of VOC based on Henry’s law to estimate the concentration of a particular contaminant in soil gas. This paper presents the results from a series of laboratory experiments concerning the use of the Henry’s Law constant for the calculation of toluene concentrations in equilibrium between ground water and soil air. A series of column experiments were conducted with various toluene concentrations in artificial (ground) water to contrast the predicted and observed (soil) air concentrations. The experiments which exclude soil material show a toluene fugacity behaviour roughly in line with Henry’s law whereas the experiments which include soil material result in equilibrium soil concentrations which were around one order-of-magnitude lower than was expected from a Henry Law-based estimation. It is concluded that for toluene inclusion of Henry’s Law in VI algorithms does not provide an adequate description of volatilisation in soils and may lead to an overestimation of health risk. Instead, a model based on a simple description of the relevant intermolecular interactions could be explored.

Vapor-liquid equilibrium modeling for binary system of R152a/R1234ze(E)

At present,the environment impact of refrigerants has been given attention.The binary mixture R152a/R1234ze(E)is an environmentally friendly refrigerant,which solves problems of poor cooling performance of the R1234ze(E)cycle and flammability of R152a.In order to obtain its basic thermal and physical parameters,it is necessary to carry out vapor-liquid equilibrium(VLE)research,and the cubic equation of states(EOS)is often used in the calculation of the thermodynamic properties of mixtures.In this paper,the VLE predicted models for R152a/R1234ze(E)in the temperature range of 298.15-328.15 K were constructed using Soave-Redlich-Kwong(SRK),Peng-Robinson(PR)equations of state(EOS)combined with van der Waals(vd W),Huron-Vidal(HV)mixing rules,respectively.The equilibrium pressures and vapor-phase mole fractions of the models were obtained by calculation,and all four models presented an extreme correlation with the experimental data.And it can be concluded that the calculated results of the PR+HV model are closer to the experimental data than those of the other three models,with the average absolute deviation of 0.0027 for vapor-phase mole fraction(AAD(ycal))and the average absolute relative deviation of 0.243%for equilibrium pressure(AARD(pcal)),which provides a basis for accurately calculating the thermophysical properties of the mixture R152a/R1234ze(E).

黄河流域河南段水资源空间均衡研究

基于水资源负载指数、水土资源匹配系数和用水效益系数等测算模型,研究了黄河流域河南段2011—2020年水资源空间均衡性.结果表明,黄河流域河南段8市水资源负载指数大致呈波动增长趋势且远大于10,水资源利用程度很高,基尼系数为0.31;水土资源匹配系数大致呈波动下降趋势且平均值为0.33,水土匹配程度较低,基尼系数为0.28;用水效益系数呈稳步上升趋势,单方水GDP产值为208元,用水效益与经济发展水平相对合理,基尼系数为0.32;水资源空间均衡系数平均值为0.55,空间均衡等级为Ⅲ级,属于一般失衡.基于此,合理配置水资源、提高用水效率、提前规划引水调水等有利于促进黄河流域河南段社会经济和水资源利用空间均衡发展.

基于双折减系数法与极限平衡法的顺层滑坡稳定性分析

以四川省布拖县龙潭乡冯家坪滑坡为例,利用FLAC3D软件设计了基于双折减系数法的滑坡稳定性分析程序,应用“GIS-Rhino-FLAC3D”耦合技术建立三维地质体模型。考虑黏聚力和内摩擦角在滑坡失稳过程中衰减速度和弱化程度的不同,以及非饱和土中基质吸力对土体抗剪强度的影响,提出一种以黏聚力和摩擦力的衰减权重定义综合安全系数的双折减系数法,并采用极限平衡法作对比计算,研究分析了顺层滑坡的稳定性。结果表明:设计的抗剪强度参数双折减程序可以得出安全系数云图,直观地反映滑坡安全系数的空间分布特征;与传统强度折减法相比,所提出的双折减系数法计算的滑动面分布范围和综合安全系数更精确,较极限平衡法误差更小,可以准确地反映滑坡的稳定状态。研究结果可为双折减系数法应用于滑坡灾害的防治提供参考。