流动电位法对甘氨酸水溶液结晶过程的表征

以流动电位法研究甘氨酸饱和水溶液降温结晶过程。考察了溶液酸度和起始温度对结晶过程中流动电位υ-结晶器温度t曲线的影响。结果表明,甘氨酸饱和溶液在较高起始温度30和35℃下成核能力较差,在较低起始温度20和25℃下成核能力较强。随着甘氨酸饱和溶液酸度的变化,相同起始温度的υ-t曲线表明成核能力有较大差异。溶液酸度为pH=7.0、pH=5.0、pH=4.0的条件下成核作用明显,但低温下成核具有较大的偶然性。等电点附近(pH=6.0)成核能力较差,容易析出不定型固体。运用生长基元理论进行了分析。

Crystallization of Glycine Characterized with Streaming Potential Measurement

The streaming potential of supersaturated solution of glycine was determined to characterize crystallization in cooling process.The influence of solution acidity and the initial temperature to the υ-t curve were investigated.The results showed that the glycine solution had more competitive nucleating ability in higher initial temperature as 30 and 35℃,and less competitive nucleating ability in lower initial temperature as 20 and 25℃.The υ-t curve of the same initial temperature for nucleating ability was very different with the acidity change of the glycine saturated solution.The solution of pH=7.0,pH=5.0 and pH=4.0 had more evidently competitive nucleating ability.However the nucleation at low temperature had higher contingency.The solution had less competitive nucleating ability at isoelectric point and formed indefinite solid and easily deposited.Growth units mode was utilized to explain the above phenomena.