(中南大學(xué) 化學(xué)化工學(xué)院 有色金屬資源化學(xué)教育部重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083)
摘 要: 采用最大氣泡壓力法測(cè)定298.15 K，常壓及不同離子強(qiáng)度(0.57~12.81 mol/kg)條件下氯化鈷水溶液體系的表面張力，建立表面張力與濃度關(guān)系的經(jīng)驗(yàn)公式。應(yīng)用Gibbs吸附等溫式推導(dǎo)出表面張力與活度的關(guān)系式，提出一種計(jì)算溶液活度因子的新模型，并利用實(shí)驗(yàn)數(shù)據(jù)回歸得出了新模型參數(shù)。與文獻(xiàn)中的數(shù)據(jù)相比，新模型計(jì)算數(shù)據(jù)的標(biāo)準(zhǔn)偏差為0.0632，與Kim歸納出的Pitzer模型參數(shù)計(jì)算數(shù)據(jù)的標(biāo)準(zhǔn)偏差相近。結(jié)果表明：采用電解質(zhì)溶液活度測(cè)定新方法和計(jì)算模型可得到的氯化鈷水溶液活度因子的精度較高，這使得通過(guò)測(cè)定電解質(zhì)溶液表面張力計(jì)算其活度因子(或活度)成為可能。
關(guān)鍵字: 電解質(zhì)溶液；活度因子；表面張力；最大氣泡壓力法；氯化鈷；吉布斯吸附等溫式
（Key Laboratory of Resource Chemistry of Nonferrous Metals, Ministry of Education,
School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China）
Abstract:The surface tension of cobalt chloride aqueous solution was determined using the maximum bubble pressure method at 298.15 K and constant pressure with ionic strength ranging from 0.57 to 12.81 mol/kg, and the empirical formula of surface tension as a function of concentration was constructed. The relationship between surface tension and activity was derived by applying Gibbs adsorption isotherm, and a new model to calculate activity coefficient was proposed and regressed based on experimental values. Compared with literature values, the standard deviation of results calculated from the new model is 0.0632, which is close to that of Pitzer equation parameters generalized by Kim. Thus, it can be concluded that the new model provides a new approach to calculate activity coefficients (or activity) of electrolyte solutions with a relatively high precision by measuring the surface tension.
Key words: electrolyte solutions; activity coefficient; surface tension; maximum bubble pressure method; cobalt chloride; Gibbs adsorption isotherm
