含氯化钠电解质水溶液体系热力学性质研究进展

总结了近几十年来含氯化钠电解质水溶液体系热力学性质的研究成果及其在盐湖、地下卤水、油田水和海盐制备等领域的应用,并对含钠水盐体系在不同温度下的热力学性质进行了总结,对于推动含钠水盐体系电解质溶液理论的发展和促进富盐湖卤水、地下卤水及海水的开发利用具有重要的意义。     

盐湖卤水体系势力学和相平衡研究进展

我国青藏高原的盐湖卤水以富含硼、锂而闻名于世。其卤水大多属于Ｌｉ＾＋、Ｎａ＾＋、Ｋ＾＋、Ｍｇ＾＋（Ｃａ＾２＋）／Ｃｌ＾－,ＣＯ３＾２－（ＨＣＯ３＾－）、ＳＯ４＾２－,ｂｏｒａｔｅ－Ｈ２Ｏ体系。它具有某些特殊的性质,被称之为“盐湖卤水体系”。它的研究在理论和实践上都有重要价值。我们对其热力学和相平衡进行了长期研究,积累了大量数据。用Ｐｉｔｚｅｒ电解质溶液模型描述了这一体系的热力学和相平衡及其它物化性     

盐湖卤水体系热力学和相平衡研究进展*

我国青藏高原的盐湖卤水以富含硼、锂而闻名于世。其卤水大多属于Li⁺、Na⁺、K⁺、Mg²⁺(Ca²⁺)/Cl^-,CO^2-₃(HCO^-₃)、SO^2-₄,borate-H₂O体系。它具有某些特殊的性质,被称之为“盐湖卤水体系”。它的研究在理论和实践上都有中药价值。我们对其热力学和相平衡进行了长期研究,积累了大量数据。用Pitzer电解质溶液模型描述了这一体系的热力学和相平衡及其它物化性质。以Li⁺,K⁺,Mg²⁺/Cl^-,SO^2-₄-H₂O,体系25^。C时相平衡的预测为例,证明模型的可信性和用途。     

硝酸盐型卤水体系的综合热力学模型与多温相图预测

硝酸盐型卤水是盐湖卤水、 硝酸盐工业、 废水处理中普遍遇到的电解质溶液体系. 硝酸盐具有极高的溶解度, 实现硝酸盐型复杂电解质体系物性和相平衡的精准热力学表达依然具有挑战性. 以煤化工废水的典型体系Na⁺//NO₃^- , Cl^-, SO₄^{2 -} -H₂O为对象, 以改进的eNRTL模型为基础, 由活度系数模型、 溶液物性模型、 物种热力学模型和固液相平衡模型构成了电解质体系的综合热力学模型. 利用二元体系的冰点、 饱和蒸汽压、 等压摩尔热容、 活度系数和渗透压系数等物性数据和三元体系等温相平衡数据, 采用多目标优化方法, 获得了表达研究体系的多温特性的12组液相特征参数和7个固相物种的热力学参数. 据此完成了3个二元体系、 3个三元体系等温相平衡的准确计算和三元、 四元完整相图的预测, 适用温度达到实验所及的全部温度范围(254.65~543.15 K); 适用浓度达到饱和程度, 其中NaNO₃的浓度高达226.88 mol/kg. 三元、 四元体系的多温相图预测结果与实验数据相吻合, 并给出了9个三元、 5个四元体系零变点的完整信息.     

多元气-液-固复杂体系相平衡

石油流体中含有气相、液相及可能遇到的固相包括水合物、石蜡和沥青质等,涉及多元气-液-固复杂体系的相平衡问题.为防止这些沉积物堵塞造成安全隐患,需要确定水合物、石蜡、沥青质沉积起始条件以及沉积量.本文针对化学热力学理论在含水合物、石蜡和沥青质的多元-多相平衡研究中的应用进行了综述.水合物相平衡模型较为成熟,主要有两类,其一为基于等温吸附理论的van der Waals-Platteeuw型热力学模型;其二为基于双过程水合物生成机理的Chen-Guo水合物热力学模型.石蜡沉积一般采用活度系数法、状态方程法及多固相模型描述.沥青质絮凝、沉积则可采用溶解度参数模型、状态方程法、胶体模型和标度理论模型进行计算.同时对多元气-液-固复杂体系的相平衡研究发展方向进行了展望.     

稀碱金属铷、铯盐-混合溶剂多元体系相平衡研究进展

稀碱金属铷、铯资源的成功开发,需以相应的相平衡与相图研究成果为指导,开展稀碱金属盐-混合溶剂体系相平衡的研究,对这些金属盐的提纯开发利用具有重要的意义.本文主要从不同的铷、铯盐-混合溶剂三元及四元体系两个方面,归纳总结了此类体系的相平衡研究进展,探讨了研究中存在的一些问题,为深入研究稀碱金属-混合溶剂体系的相平衡奠定了基础.     

四元交互体系Li~+,K~+/Cl~-,CO_3~(2-)-H_2O在298K时相平衡及物理化学性质研究

位于我国西藏腹地的扎布耶盐湖 ,是世界上罕见的富含锂、钾等碱金属和富含硼的碳酸盐 硼酸盐的特种盐湖 .该湖卤水主要由Ｌｉ+,Ｎａ+,Ｋ+,Ｃｌ- ,ＣＯ2 -3 ,ＳＯ2 -4 ,Ｂ4Ｏ2 -7,ＨＣＯ-3 等物种构成 .显然 ,开展该湖卤水体系的理论和实验相平衡研究 ,不仅对该种类型盐湖卤水的成因和成矿规律、对于这类复杂水盐体系化学行为的理论和实验描述研究具有重要意义 ,而且对于该盐湖卤水盐类资源综合利用方案的制定具有指导意义 .但是 ,迄今为止 ,除陈郁华[1 ] 报道过关于 2 98Ｋ条件下该湖卤水体系等温蒸发实验研究的结果外 ,尚未见到关于该湖卤…     

Li+,K+/Cl-,CO32--H2O四元交互体系(298K)介稳相平衡的实验研究

我国西藏的扎布耶盐湖卤水以富含硼、锂、钾而闻名于世[1-2]。依据扎布耶盐湖卤水体系的主要成分,该卤水体系可简化Li K Na B4O72- CO32- Cl- SO42- H2O体系。针对西藏盐湖地处干旱、强日照特点,开展对扎布耶盐湖卤水体系的多温稳定及介稳相平衡研究,对于解释盐湖的演化及指     

原子吸收分光光度法测定镁、钙和锶

研究了在空气-乙炔焰中测定镁、钙和锶时的电离干扰和化学干扰。在此基础上,提出两项措施:在干扰效应可忽略的火焰高度处测量吸收值;控制试样中干扰物的浓度。分析卤水这样复杂体系中的镁、钙和锶时,应使喷雾液中含Na~ 40-1000微克/毫升作为电离阻止剂,含La~(3 )3000微克/毫升作为释放剂,以克服电离干扰及化学干扰,所得结果准确,分析步骤亦较简便、快速。     

南翼山油田水中锶的容量分析

在对EDTA络合滴定法测定南翼山油田水中锶的分析条件研究过程中,对指示剂、分析体系环境、沉淀煮沸时间、沉淀冷却时间以及钙对锶的干扰进行了讨论,对行业标准HG/T 2958.1-1988(1997)<天青石矿石中锶和钙含量的测定-EDTA容量法>中锶的分析方法进行了改进,以改进后的方法为依据,建立了高钙体系中锶的容量分析方法,该方法的重现性和准确度较好.本方法不仅适用于油田水体系,而且也适用于盐湖卤水体系.     

Qualities of models for evaluation,representation and prediction of fluid phase equilibrium data

After defining a model for fluid phase equilibria in the framework of classical thermodynamics, the methods of building models and obtaining parameters from experimental data are briefly reviewed. A personal view is given on models and methods useful at various stages of the scientific process of understanding fluid phase equilibria, especially vapour-liquid equilibria i.e. the evaluation of experimental data and the search for physical significance. The needs for research with a view to its application are considered.     

Calculation of phase equilibria in random copolymer systems

Synthesis and application of copolymers are not seldom connected with different phase equilibria. Their precise knowledge is of importance for industrial processing as well as it is a profound basis for a better understanding of the nature and thermodynamics of such systems. As a common situation today, enough experimental information is seldom available in the necessary or desired amount, and a lot of model calculation is, therefore, more or less unavoidable to cover the desired ranges of application. Different equations-of-state as well as lattice models are discussed with respect to their applicability for calculating liquid-liquid and gas-liquid phase equilibria in copolymer solutions and blends. Examples for high-pressure phase equilibria in monomer/copolymer mixtures, liquid-liquid demixing in copolymer blends and for the isotropicnematic phase equilibrium in systems with rigid rod-like copolymers characterized by distributions of rigid and flexible chain parts are given. The effects of copolymer polydispersity are included by means of continuous thermodynamics. Literature references for original sources, earlier reviews and further applications round up this paper.     

Third law of thermodynamics as applied to phase diagrams

Consequences from the third law of thermodynamics are analyzed from the standpoint of low-temperature phase equilibria. The kinetics of attainment of low-temperature equilibria and some ordering and decomposition features of solid solutions are considered.     

Molecular Thermodynamics for Chemical Process Design

Thermodynamic properties are essential for quantitative process design to produce chemical products. Caloric properties are required for heat balances, but these properties are usually available or estimated easily. More important—and often much more difficult to estimate—are the chemical potentials of components in mixtures; it is these potentials which determine phase equilibria, as required for separation operations, and chemical equilibria, as required for chemical reactors and for separation operations based on chemical reactions. Molecular thermodynamics is an engineering-oriented science for calculating the desired chemical potentials from a minimum of experimental data. This applied science, based on classical and statistical thermodynamics, yields chemical potentials through models that are based on molecular physics and physical chemistry. Selected examples are cited to illustrate the applicability of molecular thermodynamics: group-contribution methods for obtaining chemical potentials in highly nonideal mixtures as required for distillation-column and process-safety design; equation of state for precipitation of uniform-sized crystals from supercritical fluids; molecular-orbital calculations to guide process development for alternatives to environmentally dangerous chlorofluorohydrocarbons; molecular-simulation calculations for separation of gas mixtures with porous adsorbents; equilibria in two-phase aqueous systems for separation of protein mixtures; and, finally, extended polymer-solution thermodynamics to guide synthesis of hydrogels suitable for protein recovery from soybeans and for novel drug-delivery devices.     

The Thermodynamics of Insertion Electrochemical Electrodes—A Team Play of Electrons and Ions across Two Separate Interfaces

Insertion electrochemical electrodes exhibit simultaneous electron and ion transfer, with the two transfers proceeding across different interfaces. Herein the thermodynamics of the overall electrochemical electrode reaction is discussed with respect to the thermodynamics of these two charge‐transfer equilibria. This Minireview includes insertion electrochemical systems where the redox centers are in a solid phase and the ions are transferred between that phase and a solution, and also systems where the redox centers are in a liquid phase that is immiscible with another liquid phase and ions are transferred between the two liquid phases. The Minireview is intended to spark similar studies on battery materials to improve their performance.     

Molecular thermodynamics for some applications in biotechnology

As biotechnology sweeps the world, it is appropriate to remember that the great virtue of thermodynamics is its broad range of applicability. As a result, there is a growing literature describing how chemical thermodynamics can be used to inform processes for old and new biochemical products for industry and medicine. A particular application of molecular thermodynamics concerns separation of aqueous proteins by selective precipitation. For this purpose, we need phase diagrams; for constructing such diagrams, we need to understand not only the qualitative nature of phase equilibria of aqueous proteins but also the quantitative intermolecular forces between proteins in solution. Some examples are given to show how aqueous protein–protein forces can be calculated or measured to yield a potential of mean force and how that potential is then used along with a statistical thermodynamic model to establish liquid–liquid and liquid–crystal equilibria. Such equilibria are useful not only for separation processes but also for understanding diseases like Alzheimer’s, cataracts and sickle-cell anemia that appear to be caused by protein agglomeration.

     

Refined Continuous Thermodynamic Treatment for the Liquid-Liquid Equilibrium of Copolymer Solutions

Based on an improved calculation of activity coefficients, continuous thermodynamics using a generalized divariate Stockmayer distribution is applied to the liquid-liquid equilibrium of random copolymer solutions. The effects of the chemical polydispersity on the cloud-point curve, the shadow curve, the spinodal, and the critical point are discussed. The theory can account for the occurrence of three-phase equilibria as well as for the phase separation in pure copolymers.     

Calculation of phase equilibria and construction of phase diagrams by convex hull method

Recent findings for a new method developed to calculate phase equilibria are reviewed and analyzed. This method is based on the construction of the convex hulls for characteristic functions in heterogeneous systems. The theoretical basis of this method, as well as the possibilities and features of its practical application in scientific research and teaching chemical thermodynamics, is considered. Software packages developed at the Department of Chemistry of Moscow State University are briefly described.     

Au–Cu Phase Diagram

Phase equilibria have been extrapolated to low temperatures, and a condensed phase diagram has been plotted for the Au–Cu system to be consistent with the third law of thermodynamics.     

在复杂流体中的相平衡

复杂流体表现出与一般溶液不同的特性,它们常呈现更丰富和多变的性质和相行为.认识和了解复杂流体丰富多彩的相平衡知识,对于解决生产中存在的问题有重要意义.本文以复杂流体中存在的自组装结构、特殊相互作用及其独特的相行为目标,分别介绍脂质体溶液和盐湖卤水溶液中呈现的特殊相互作用、自组装体结构及其相平衡.从化学热力学的角度出发,探索在这些复杂流体中组分可能形成的自组装体,以及这些自组装体对复杂流体相行为的影响.