25℃时K_2B_4O_7-H_2O体系的离子相互作用模型研究

The Pitzer Ion-interaction Model for the K_2B_4O_7-H_2O System at 298.15 K

根据硼酸盐水溶液中硼浓度不同时硼物种之间形成多种聚合与解聚的平衡反应理论和光谱学研究结果,利用已有的该体系25℃等压实验数据,拟合获得了该体系的两个化学计量平衡常数、各种硼氧配阴离子单一的以及二离子和三离子之间的相互作用Pitzer参数,确定了该体系在不同总硼浓度范围内各种硼氧配阴离子的存在形式与定量分布,将所获得的离子相互作用模型计算出的渗透系数与实验值进行了比较,获得了令人满意的结果。

The Pitzer ion-interaction model has been used for describing isopiestic osmotic coefficients of the K_2B_4O_7-H_2O system at 298.15K by mean of the of Platford's experimental data. The optimum values of the single-salt, binary and ternary parameters of ionic interaction for the above system have been calculated by considering the structure studies results that several polyborate species may be present in the same solution containing boron. The stoichiometric equilibrium constants and the distributions of concentrations among various polyborate species are evaluated in different range of total-boron concentrations.Good agreement between experimentally determined and calculated osmotic coefficients using Pitzer parameters obtained in this study has been found with standard deviations of 0.004561 for K_2B_40_7 aqueous solution.