Bley Michael, Duvail Magali, Guilbaud Philippe, Dufrêche Jean-François
ICSM, CEA, CNRS, ENSCM, Univ Montpellier , BP 17171, F-30207 Bagnols-sur-Cèze , France.
Nuclear Energy Division, Research Department on Mining and Fuel Recycling Processes (SPDS/LILA) , CEA , BP 17171, F-30207 Bagnols sur Cèze , France.
J Phys Chem B. 2018 Aug 9;122(31):7726-7736. doi: 10.1021/acs.jpcb.8b04950. Epub 2018 Jul 26.
Osmotic and activity coefficients of three aqueous electrolyte solutions with cations of similar ionic radius, but different charges, are described by molecular dynamics with the help of the osmotic equilibrium method using polarizable force fields up to high concentration. Simulations of vapor-liquid interfaces of aqueous solutions of NaNO, Ca(NO), and Eu(NO) at different concentrations and at 298.15 K provide time-averaged number density profiles and consequently the quantity of solvent molecules in the vapor phase. These three cations of similar ionic radii exhibit an increasing amount of water in their first coordination sphere due to their increasing charge. The solvent activity is directly determined by the vapor phase density at different salt concentrations with respect to the vapor phase density of the pure solvent. The obtained densities of the liquid bulk and the osmotic and activity coefficients for the three different nitrate salts are in good agreement with the experimental results. Time-averaged concentration profiles and the interpretation of radial distribution functions are used to explain the role of coordination on the thermodynamic properties of aqueous electrolyte solutions.
利用极化力场，借助渗透平衡法，通过分子动力学描述了三种阳离子具有相似离子半径但电荷不同的电解质水溶液的渗透系数和活度系数，模拟范围直至高浓度。在298.15 K下，对不同浓度的硝酸钠、硝酸钙和硝酸铕水溶液的气液界面进行模拟，得到了时间平均数密度分布，从而得出了气相中溶剂分子的数量。这三种具有相似离子半径的阳离子由于电荷增加，其第一配位层中的水量也在增加。溶剂活度由不同盐浓度下的气相密度相对于纯溶剂的气相密度直接确定。所得到的三种不同硝酸盐的液体本体密度、渗透系数和活度系数与实验结果吻合良好。利用时间平均浓度分布和径向分布函数的解释来阐述配位作用对电解质水溶液热力学性质的影响。
