Li Ke-Bin, Zhang Tao, Wei Hong, Chen Jing-Tao, Liu Fei
Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry & Materials Science, Northwest University, Xi' an 710069, China.
Huan Jing Ke Xue. 2009 Sep 15;30(9):2586-91.
Chitosan was used for the removal of Acid Red 3R from aqueous solutions. Batch adsorption studies were carried out to investigate adsorption kinetics and thermodynamics and the effect of coexisting pH, NaCl, and Cu2+ on adsorption. Experimental data were exploited for kinetic and thermodynamic evaluations related to the adsorption processes. The kinetic data correlated well with the pseudo-second-order kinetic model, indicating the chemical sorption via complex formation/ion exchange. The equilibrium data were well fitted by three isotherm models, namely, Langmuir, Freundlich and Dubinin-Radushkevich (D-R) equations. Moreover, adsorption of Acid Red 3R onto the chitosan was found to be strongly depending on solution temperature and pH. However, the addition of sodium chloride was found to have little effect on the adsorption process. Thermodynamic studies revealed the adsorption process was exothermic in natural. The adsorption free energies derived from D-R equation were in range of 9.5-10.7 kJ x mol(-1), implying that the sorption process is a chemical ion-exchange mechanism. In addition, adsorption capacity of chitosan to Acid Red 3R was found to be greatly enhanced in the presence of Cu2+. A model correlating the concentration of Cu2+ with the enhanced amount of dye adsorbed was established.
壳聚糖用于从水溶液中去除酸性红3R。进行了批量吸附研究，以考察吸附动力学、热力学以及共存的pH值、氯化钠和铜离子对吸附的影响。利用实验数据对吸附过程进行动力学和热力学评估。动力学数据与伪二级动力学模型拟合良好，表明通过络合物形成/离子交换进行化学吸附。平衡数据能很好地拟合三种等温线模型，即朗缪尔、弗伦德里希和杜宾宁-拉杜什凯维奇（D-R）方程。此外，发现酸性红3R在壳聚糖上的吸附强烈依赖于溶液温度和pH值。然而，发现添加氯化钠对吸附过程影响很小。热力学研究表明吸附过程本质上是放热的。由D-R方程得出的吸附自由能在9.5-10.7 kJ·mol⁻¹范围内，这意味着吸附过程是一种化学离子交换机制。此外，发现在铜离子存在下壳聚糖对酸性红3R的吸附容量大大提高。建立了一个将铜离子浓度与增强的染料吸附量相关联的模型。
