Desorption of zinc by the kaolin from Suzhou, China

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• 作者：Shengli Wang ; Zhongren Nan ; Jingjing Zeng ; Tingting Hu
• 关键词：Desorption ; Zinc ; Kaolin ; Percent desorption ; Thermodynamic parameters
• 刊名：Applied Clay Science
• 出版年：2007
• 期刊代码：5_01691317
• 类别：ms
• 出版时间：September 2007
• 卷：37
• 期：3-4
• 页码：221-225
• 文件大小：227 K

摘要

This paper studied the influence of copper concentration, pH, temperature, and the ratio of solid to solution on desorption of Zn in the kaolin from Suzhou, China in a background solution of 0.01 M CaCl₂ by batch extraction experiments. At 0, 5, 50, 100 mg/l Cu concentration, for each 0.5 increase in pH between about 1.80 and 3.04%desorption decreases 3.80, 13.87, 9.97, and 7.65%, respectively. The pH₅₀ (pH at 50%Zn desorption) is found to follow the sequence: Cu (5 mg/l, pH₅₀ = 2.60) < Cu (50 mg/l, pH₅₀ = 2.70) < Cu (100 mg/l, pH₅₀ = 2.95) < Cu (0 mg/l, pH₅₀ = 10.65). The free energy change (ΔG) values, the values of enthalpy change (ΔH), and entropy change (ΔS) have been calculated. There were no large differences in the desorption of Zn from 25 to 50 °C. The concentration of Zn in solution after desorption equilibrium increases and percent desorption decreases when the solid to liquid ratio increases from 0.025 to 0.2. The kaolin possibly cannot be used for the landfill clay liner.