Cestari Antonio R, Vieira Eunice F S, Pinto Alane A, Lopes Elaine C N
Laboratory of Materials and Calorimetry, Departamento de Química/CCET, Universidade Federal de Sergipe, 49000-000 São Cristovão, Sergipe, Brazil.
J Colloid Interface Sci. 2005 Dec 15;292(2):363-72. doi: 10.1016/j.jcis.2005.05.096. Epub 2005 Jul 22.
In this work, a hybrid silica/chitosan was synthesized and characterized by nitrogen elemental analysis and thermal analysis (TG, DTG, DTA, and DSC) and BET surface area. The hybrid was used in adsorption studies of two anionic dyes from aqueous solutions. A rise of temperature accelerates mass transfer of dyes into the hybrid. However, the maximum adsorption capacities reach similar values from 25 to 55 degrees C. The kinetic data were first evaluated in relation to the decrease of the time-related residual concentration of the dyes in solution, where the second-order model has presented the best fitting. The solid-phase interaction of dye data presents a rough fitting to the traditional first-order Lagergren kinetic model. However, a modified Avrami kinetic equation was successfully fitted to the kinetic quantities, where from five to seven kinetic regions were found. A pore-diffusion model has also demonstrated that the diffusion is the rate-controlling interaction mechanism. However, the experimental-calculated comparative values are the best way to evaluate a specific aqueous- or solid-phase kinetic model.
在本研究中，合成了一种二氧化硅/壳聚糖杂化材料，并通过氮元素分析、热分析（TG、DTG、DTA和DSC）以及BET比表面积对其进行了表征。该杂化材料用于从水溶液中吸附两种阴离子染料的研究。温度升高会加速染料向杂化材料中的传质。然而，在25至55摄氏度范围内，最大吸附容量达到相似的值。首先根据溶液中与时间相关的染料残留浓度的降低来评估动力学数据，其中二阶模型拟合效果最佳。染料数据的固相互作用与传统的一级Lagergren动力学模型大致拟合。然而，修正的Avrami动力学方程成功地拟合了动力学量，在此发现了五到七个动力学区域。孔扩散模型也表明扩散是速率控制的相互作用机制。然而，实验计算的比较值是评估特定水相或固相动力学模型的最佳方法。
