Adsorption behavior of reactive dye in aqueous solution on chemical cross-linked chitosan beads
Adsorption behavior of reactive dye in aqueous solution on chemical cross-linked chitosan beads
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DOI：
10.1016/s0045-6535(02)00636-7
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发表时间：
2003-03-01
期刊：
影响因子：
8.8
通讯作者：
Li, HY
中科院分区：
文献类型：
--
作者：
Chiou, MS;Li, HY
采用间歇体系研究了交联壳聚糖珠对水溶液中活性染料(活性红189)的吸附。采用离子交联剂三聚磷酸钠制备了较硬的壳聚糖珠。采用化学交联剂环氧氯丙烷(ECH)、戊二醛和乙二醇二缩水甘油醚作为交联剂，在酸性溶液中稳定壳聚糖，发现ECH具有较高的吸附容量。用Langmuir和Freundlich吸附模型描述了不同粒径下的吸附等温线，测定了吸附等温线常数。Langmuir模型与实验数据符合得很好，在pH 3.0，30℃时，其最大单层吸附容量很大，为1802-1840(g/kg)。考察了染料初始浓度、温度、pH、离子强度、湿/干球等因素对吸附动力学的影响。动力学数据用准一级、二级动力学模型和颗粒内扩散模型描述，并求出了反应速率常数。除干珠较好地符合一级动力学模型外，其余动力学数据与二级动力学模型吻合较好。吸附容量随溶液pH值的降低或初始染料浓度的增加而增大。测定了自由能(AG)、热焓(Aho)、熵(ASO)和活化能的变化等热力学参数。吸附机理为染料与壳聚糖珠之间的静电相互作用。解吸数据表明，在pH为10.0、温度为30℃的NaOH溶液中，交联壳聚糖珠对RR189染料的脱附率为63%。解吸后的壳聚糖珠可以重复使用来吸附染料，并达到解吸前的容量。(C)2002爱思唯尔科学有限公司。保留所有权利。
A batch system was applied to study the adsorption of reactive dye (reactive red 189) from aqueous solutions by cross-linked chitosan beads. The ionic cross-linking reagent sodium tripolyphosphate was used to obtain more rigid chitosan beads. To stabilize chitosan in acid solutions, chemical cross-linking reagent epichlorohydrin (ECH), glutaraldehyde and ethylene glycol diglycidyl ether was used and ECH shows a higher adsorption capacity. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms at different particle sizes and isotherm constants were determined. The Langmuir model agrees very well with experimental data and its calculated maximum monolayer adsorption capacity has very large value of 1802-1840 (g/kg) at pH 3.0, 30 degreesC. The kinetics of the adsorption with respect to the initial dye concentration, temperature, pH, ionic strength, and wet/dry beads were investigated. The pseudo-first-order, second-order kinetic models and intraparticle diffusion model were used to describe the kinetic data and the rate constants were evaluated. The dynamical data fit well with the second-order kinetic model, except for the dry beads fitting better with the first-order model. The adsorption capacity increases largely with decreasing solution pH or with increasing initial dye concentration. Thermodynamic parameters such as change in free energy (AG), enthalpy (AHO), entropy (ASO) and activation energy were also determined. The adsorption mechanism is shown to be the electrostatic interactions between the dye and chitosan beads. The desorption data shows that the removal percent of dye RR 189 from the cross-linked chitosan beads is 63% in NaOH solutions at pH 10.0, 30 degreesC. The desorbed chitosan beads can be reused to adsorb the dye and to reach the same capacity as that before desorption. (C) 2002 Elsevier Science Ltd. All rights reserved.