采用半经验水化模型计算NaH2PO4-K2HPO4混合电解质溶液冰点

Calculating freezing point of NaH2PO4-K2HPO4 mixed electrolyte solution with semi-empirical hydration model

测定冰点的常用方法如步冷曲线冰点测定法及空气湿度冰点测定法的结果通常会受仪器、环境和操作者等多种因素的影响,且费时费力。本文应用了一种电解质溶液体系半经验水化模型(semi-empirical hydration model,SEHM),以NaH2PO4和K2HPO4组成的混合电解质溶液为例,由溶液中各溶质的质量摩尔浓度计算溶剂水的活度,进而计算出溶液的冰点,并将计算结果与步冷曲线冰点测定法和空气湿度冰点测定法得到的冰点值进行比较。结果表明,采用SEHM计算得到的冰点值与步冷曲线法和空气湿度法得到的冰点值基本一致。此法无需实验,通过计算得到冰点值,提高工作效率,节约成本。

The methods for determination of freezing point include cooling curve cryoscopy and air humidity cryoscopy.These methods are usually influenced by many factors,such as instrumentation,environment and operators.Despite the numerous experimental methods,precise freezing point values are challenging to obtain due to time-consuming procedures,limited sample size and extensive manual work.In this study,a semi-empirical hydration model(SEHM)was developed to calculate freezing point of NaH2 PO4-K2 HPO4 mixed electrolyte solution.According to SEHM,the water activity of mixed electrolyte solution was calculated by molality of solutes.Then the freezing point of solution was calculated.The calculated results were compared with those obtained by cooling curve cryoscopy and air humidity cryoscopy.The results indicate that the SEHM calculations are comparable to the measurements of cooling curve cryoscopy and air humidity cryoscopy.