電荷可調節性粒子的電泳:溫度、pH及離子濃度之影響

Abstract

本論文以分散於一相對稀薄的NaCl水溶液(濃度為CNaCl)之球型SiO2粒子為例，研究溫度對電荷可調節粒子電泳行為的影響。由於SiO2粒子同時具酸性與鹼性特質，其表面帶電情況需以電荷可調節模式描述。另外，因為溶液的pH為透過NaOH和HCl之添加來調節，需要考慮多種離子的存在。這些變因使得傳統電泳模型無法描述所考慮的問題，必須作適當的延伸。吾人針對pH介於3至9.5，CNaCl介於10−4到10−2 M，以及溫度介於293和308 K之間的範圍建立完整的電泳遷移率-pH-溫度，與電泳遷移率-CNaCl-溫度的圖形，並提供經驗迴歸式。整體而言，粒子電泳遷移率的絕對值會隨溫度增加而增加，且當pH改變時會出現局部極值。由於焦耳熱效應的關係，電泳過程中溫度的變化一般無法避免；即使在一溫控良好的系統中，吾人亦可藉由溫度的調整達到控制電泳速度的目的。因此，本文所獲結果提供了闡述實驗數據及設計電泳儀器必要的資訊。

The influence of temperature on the electrophoretic behavior of a charge-regulated particle is investigated by considering a spherical SiO2 particle in a relatively dilute aqueous NaCl solution of concentration CNaCl with its pH adjusted by NaOH and HCl as an example. A complete mobility-pH-temperature plot and a mobility-CNaCl-temperature plot are prepared for pH, CNaCl, and temperature ranging from 3 to 9.5, 10−4 to 10−2 M, and 293 to 308 K, respectively, for the first time, and empirical correlation relationships are developed. These provide necessary information for both interpreting experimental data and designing electrophoresis devices, where the variation in the temperature can be a factor. In general, the absolute value of the particle mobility increases with T, and that value has a local maximum as pH varies.