Cestari Antonio R, Vieira Eunice F S, Lopes Elaine C N, da Silva Roberto G
Laboratory of Materials and Calorimetry, Departamento de Química/CCET, Universidade Federal de Sergipe, 49000-000 São Cristovão, Sergipe, Brazil.
J Colloid Interface Sci. 2004 Apr 15;272(2):271-6. doi: 10.1016/j.jcis.2003.09.019.
Sílica-dithizone (Sil-dtz) was synthesized and used to adsorb Hg(II) in solution at pH 6.0. Increasing the temperature accelerates the mass transfer of Hg(II) to the silica surface. The kinetic data were evaluated using the traditional pseudo-first-order Lagergren equation and an alternative Avrami kinetic equation. From the latter equation, two regions presenting distinct kinetic parameters were found, at 25 and 35 degrees C, and the use of the parameter n was also related to the determination of distinct kinetic orders. Variations of the adsorption kinetic rate in relation to the time and the temperature were also calculated and are discussed. The adsorption isotherms data were well fitted to the Freundlich model. Interestingly, good adsorption data correlation of the Langmuir model and experimental values was observed only at 45 and 50 degrees C, suggesting, for this temperature range, the formation of complexes with the proportion Hg:dithizone 1:1 on the silica surface.
合成了硅胶-双硫腙（Sil-dtz）并用于在pH 6.0的溶液中吸附Hg(II)。升高温度会加速Hg(II)向硅胶表面的传质。使用传统的伪一级Lagergren方程和另一种Avrami动力学方程对动力学数据进行了评估。从后一个方程中发现，在25和35摄氏度时存在两个呈现不同动力学参数的区域，并且参数n的使用也与不同动力学级数的确定有关。还计算并讨论了吸附动力学速率相对于时间和温度的变化。吸附等温线数据与Freundlich模型拟合良好。有趣的是，仅在45和50摄氏度时观察到Langmuir模型与实验值之间具有良好的吸附数据相关性，这表明在该温度范围内，硅胶表面形成了Hg:双硫腙比例为1:1的配合物。
