基于微扰理论和平均球近似的强电解质水溶液分子热力学模型

用平均球近似处理离子-离子间的静电相互作用,用微扰理论处理电解质溶液中各种粒子间的其他相互作用,建立了一个强电解质水溶液的分子热力学模型。该模型将阳离子直径作为唯一的可调参数,对52种1-1、1-2、2-1、2-2型强电解质水溶液离子的平均活度系数进行了关联,与现有模型比较,该模型形式相对简单,具有很好的适用性和满意的计算精度。     

基于冶金热力学的钢液定氧探头氧浓度单位确定

对比分析了以上海贺利氏电测骑士有限公司生产的Celox钢液定氧探头测量的氧活度和文献中报道的氧活度、LF精炼过程中基于[Al]-[O]平衡计算的铝镇定钢液的氧活度及顶底复吹转炉冶炼终点基于[C]-[O]平衡计算的氧活度. 结果表明,该探头测量的氧活度是以1%溶液为标准态,百万分之一氧([10-6 O])为浓度单位,而不是冶金热力学中以氧的质量百分含量([%O])为浓度单位定义的氧活度. 因此,选用氧的质量百分含量[%O]时,Celox钢液定氧探头测量的氧活度量纲应为10-4,而不是其探头仪表显示的10-6.     

CaO-SiO_2-MgO-Al_2O_3渣系与碳饱和铁液间硫分配比的热力学模型

CaO-SiO2-MgO-Al2O3渣系中结构单元或离子对的质量作用浓度能够像传统意义上的活度一样表征其反应能力.基于离子与分子共存理论,通过计算高炉炉渣中结构单元或离子对的质量作用浓度,建立了计算CaO-SiO2-MgO-Al2O3高炉渣系与碳饱和铁液间硫分配比的通用热力学模型.计算出的总的硫分配比与脱硫实验实测的硫分配比结果相吻合.此外,通用热力学模型能够定量地计算出渣中自由CaO和自由MgO各自对炉渣脱硫的贡献.1773K时,自由CaO对炉渣脱硫有97%的贡献,而自由MgO的贡献只有3%.     

NH_3-H_3PO_4-H_2O体系汽液平衡的测定与热力学平衡计算

采用静态法测定了NH_3-H_3PO_4-H_2O体系在NH_3/H_3PO_4分子比为1.0-1.4,相应温度范围为75-175℃时的汽液平衡数据,并把实验数据关联成数学式.根据热力学理论,对NH_3-H_3PO_4-H_2O体系的热力学平衡计算的模型作了初步探讨.液相活度及活度系数采用扩充Pitzer方程,汽相逸度系数采用根据极性修改的RK方程.根据Edwards提出的弱电解质溶液的分子热力学,基于质量平衡、化学平衡、电荷平衡及汽液平衡理论,提出了NH_3-H_3PO_4-H_2O体系汽液平衡计算的热力学模型.计算结果表明:摩尔浓度低于25mol/kg H_2O时,模型计算结果与实验数据吻合得较好.     

强电解质混合物水溶液粘度的计算

本文介绍一种用离子贡献法计算强电解质水溶液粘度的通用模型。此模型不仅可以计算单一强电解质水溶液在各种温度和浓度下的粘度、而且还可以计算多种强电解质混合物在各种温度和浓度下的粘度。经过实践证明、精确度能满足工程设计的要求。     

利用变阱宽方阱链流体状态方程计算1：1电解质溶液热力学性质

将变阱宽方阱链流体状态方程拓展到1：1强电解质水溶液热力学性质的计算中,通过关联溶液的平均离子活度系数和溶剂的渗透系数得到了22种离子的链节直径和方阱能量参数,40余种电解质溶液的平均离子活度系数和溶剂渗透系数的总平均相对偏差分别为6.03%和5.83%。计算结果表明,建立的电解质型状态方程可以满意预测电解质溶液的密度和宽广温度下溶液的蒸气压,总体平均相对偏差分别为0.22%和4.69%。进一步说明模型参数的可靠性。     

高压下NH_3-H_2O-CO_2-N_2-H_2五元系汽液平衡测定和计算

本文从实用目的出发,提供一个高压下NH_3-H_2O-CO_2-N_2-H_2五元体系汽液平衡计算模型.本模型结构为:(1)以NH_3-H-2O-CO_2三元系为基础,液相内的平衡运用分子热力学原理——离解平衡、电荷平衡、质量平衡三原则;并以Prausnitz提供的NH_3-H_2O二元系双曲正切函数活度系数模型为骨架,建立了宽广的氨水浓度范围内[NH_310一90%(mass)]的NH_3-H_2O-CO_2三元系的汽液平衡计算方法.(2)对于高压下NH_3-H_2O-CO_2-N_2-H_2五元系,汽相非理想性,本文用PHS状态方程计算汽相逸度系数.本模型的适用性已被实验测定值及文献数据所证实,实验值与计算值一致.     

强电解质标准生成热的计算

本文介绍用离子贡献法计算水溶液中强电解质标准生成热和固体电解质的标准生成热,以及水溶液中离子标准生成热的计算。为了读者使用本法计算强电解质标准生成热的方便,文中还列出了部分离子的标准生成热和部分电解质的溶解热,供读者参考。     

硫酸体系中N235萃取铼的热力学研究

以萃取剂N235,稀释剂正庚烷,研究萃取铼的热力学。在N235+(NH4)ReO4+n-C7H16+H2SO4+H2O体系中,温度278.15—298.15 K和离子强度0.1—2.0 mol/kg范围内,以(NH4)2SO4为支持电解质,在H2SO4体系中测定了萃取平衡水相中ReO4-质量摩尔浓度和pH值。计算了萃取反应的标准平衡常数K,并得到经验公式,同时计算了萃取反应的其他热力学量,指出熵和焓都是该萃取过程的推动力。     

挥发性弱电解质水溶液三元系的汽液平衡——NH_3-CO_2-H_2O,NH_3-H_2S-H_2O,NH_3-SO_2-H_2O体系

在Edwards通用性分子热力学模型中增加了三元相互作用项,应用优化若干可调参数的方法研究了弱电解质水溶液三元系的汽液平衡.编制了通用性FORTRAN计算程序PARA_9,在TQ-16机上实施.该程序具有弹性功能:可以直接计算,亦可优化参数.对NH_3-CO_2-H_2O、NH_3-H_2S-H_2O、NH_3-SO_2-H_2O三个体系进行处理获得满意结果,平均相对误差5—10%.同时给出了几组可调参数数值,并得到了溶液中离子和分子的活度系数,平衡浓度等有价值的信息.     

A method to apply Zavitsas' aqueous electrolyte model to multicomponent solutions and its equivalence to Zdanovskii's rule

Zavitsas developed an aqueous electrolyte thermodynamic model and applied it to single electrolyte solutions previously. Here, a method to apply the model to multicomponent solutions is derived by setting the water activity to the mole fraction of free water in the mixture. The method is shown to work effectively for the CsBr-KNO₃-H₂O and CsCl-KNO₃-H₂O systems at 100.3°C even at concentrations greater than 6 molal. The largest error in the prediction of water activities was just −0.00365 for the CsBr-KNO₃-H₂O system and −0.00631 for the CsCl-KNO₃-H₂O system. Zavitsas' model naturally obeys Zdanovskii's rule because when two electrolyte solutions with the same fraction of free water are mixed together, water is obviously going to have that same fraction in the mixture. This means that Zavitsas' model will likely work well for the many electrolytes that obey Zdanovskii's rule.     

含盐溶液汽液平衡预测(Ⅰ)——Pitzer模型的扩展及其在多元体系中的应用

本文提出一种新的预测含盐溶液汽液平衡的方法.对Pitzer(1980)模型进行扩展后,将其简化成单参数形式,推广至多元电解质溶液;经过适当假定,得到计算含盐挥发性强电解质和水体系及含盐水醇体系的活度系数公式,这些公式仅含二元相互作用参数;由二元溶液的活度关联出该参数后,可用于含盐体系各种温度下汽液平衡的预测.关联了40个二元电解质水溶液及7个电解质甲醇溶液298.15K时的简化Pitzer方程的单参数;用以推算6个水盐体系和2个甲醇盐体系在320-403K的蒸汽压,得到满意的结果,182个数据点的平均偏差小于0.65kPa;用以预测5个不同类型的含盐三元体系的等温、等压汽液平衡,所得的平均偏差对于汽相组成、沸点、压力分别为0.015、1K和1.92kPa.     

含盐溶液汽液平衡预测

本文提出一种新的预测含盐溶液汽液平衡的方法。对Pitzer(1980年)模型进行扩展后,将其简化成单参数形式,推广至多元电解质溶液;经过适当假定,得到计算含盐挥发性强电解质和水体系及含盐水醇体系的活度系数公式,这些公式仅含有二元相互作用参数;由二元溶液的活度关联出参数后,可用于含盐体系各温度下汽液平衡的预测。关联了四十个二元电解质水溶液及七个电解质甲醇溶液298.15K时的简化Pitzer方程的单参数;用以推算六个水盐体系和二个甲醇盐体系在320-403K的蒸汽压,得到满意的结果,182个数据点的平均偏差小于0.65kPa;用以预测五个不同类型的含盐三元体系的等温、等压汽液平衡,所得的平均偏差对于汽相组成、沸点、压力分别为0.015、1K、1.92kPa。     

N-异丙基丙烯酰胺凝胶在NaCl水溶液中溶胀行为的预测研究

In this paper,a model is presented to correlate and predict the swelling behavior of hydrogels in aqueous solutions of electrolytes.The model is a combination of VERS-model,"phantom network" theory and "free-volume"contribution.The VERS-model is used to calculate Gibbs excess energy; "phantom network" theory to describe the elastic properties of polymer network,and "free-volume" contribution to account for additional difference in the size of the species.To test the model,a series of N-isopropylacrylamide based hydrogels are synthesized by free radical polymerization in oxygen-free,deionized water at 25°C under nitrogen atmosphere.Then,the degree of swelling of all investigated gels as well as the partition of the solute between the gel phase and the surrounding coexisting liquid phase are measured in aqueous solution of sodium chloride.The model test demonstrates that the swelling behavior correlated and predicted by the model agrees with the experimental data within the experimental uncertainty.The phase transition appeared in the experiment,and the influences of the total mass fraction of polymerizable materials ξgel as well as the mole fraction of the crosslinking agent yCR on the swelling behavior of IPAAm-gels can also be predicted correctly.All these show the potential of such model for correlation and prediction of the swelling behavior of hydrogels in aqueous solutions of electrolytes.     

改进的UNIQUAC模型在非离子表面活性剂溶液中的应用

将非离子表面活性剂划分为链节,建立了一个计算混合Gibbs自由能的分子热力学模型,对不同温度下的5个非离子表面活性剂-水体系的临界胶束浓度进行了关联,并利用得到的参数预测了不同温度下其他14个表面活性剂体系的临界胶束浓度,关联与预测结果均令人满意。与Chen-NRTL模型相比,本模型计算精度较好,具有预测功能。     

Cation Exchange and Sorption Properties of Aluminum Phosphate

ABSTRACT

The ion-exchange properties of amorphous aluminum phosphate have been studied in aqueous electrolyte solutions of KCl over a temperature range of 300–320 K. The data were explained by the law of mass action. Sorption of Cu²⁺, Ni²⁺, and Co²⁺ on AIPO₄ was also studied as a function of temperature and concentration, and the data were fitted to Langmuir adsorption equations. In all cases the adsorption was found to increase with increases in temperature and concentration in the selectivity order Cu²⁺ > Co²⁺ > Ni²⁺. Further, the values of Langmuir constants were used to calculate the thermodynamic parameters δS°, δH°, and δG°.     

二水硫酸钙在铵盐溶液中溶解度测定及热力学计算

利用溶解法测定了二水硫酸钙(CaSO4×2H2O)在NH4Cl-H2O体系和NH4Cl-(NH4)2SO4-H2O体系中298.15~343.15 K温度范围内的溶解度. 结果表明,CaSO4×2H2O在2个体系中的溶解度均随NH4Cl浓度增加而增大;温度对CaSO4×2H2O的溶解度影响不明显. 利用混合电解质NRTL模型对实验数据进行模拟计算,得到了新的能量相互作用参数,建立了CaSO4×2H2O(s)-NH4Cl-(NH4)2SO4-H2O体系的混合电解质模型,计算值与实验值相对偏差为2.36%.     

Predicting the thermodynamic properties and dielectric behavior of electrolyte solutions using the SAFT‐VR+DE equation of state

We extend the SAFT‐VR+DE equation of state to describe 19 aqueous electrolyte solutions with both a fully dissociated and a partially dissociated model. The approach is found to predict thermodynamic properties such as the osmotic coefficient, water activity coefficient, and solution density, across different salt concentrations at room temperature and pressure in good agreement with experiment using only one or two fitted parameters. At higher temperatures and pressures, without any additional fitting, the theory is found to be in qualitative agreement with experimental mean ionic activities and osmotic coefficients. The behavior of the dielectric constant as a function of salt concentration is also reported for the first time using a statistical associating fluid theory (SAFT)‐based equation of state. At high salt concentrations, the stronger electrostatic interactions between the ionic species due to the dielectric decrement, is captured through the inclusion of ion association. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3053–3072, 2015     

Binary ion exchange equilibrium for Ca2+, Mg2+, K+, Na+ and H+ ions on amberlite IR-120

Experimental data are reported for ion exchange equilibria of binary systems on Amberlite IR-120 resin, at different temperatures and total ionic concentrations in aqueous solutions. These systems exhibit non-ideal behaviour in both phases, and the equilibrium characterization has been based on the law of mass action, using Wilson and Meisssner, and Kusik equations to correlate the activity coefficients in the resin and aqueous solutions, respectively. Equilibrium constants, standard thermodynamic properties (Gibbs free enthalpy changes, enthalpy and entropy) and Wilson binary parameters were obtained as functions of temperature.