活性炭/壳聚糖多孔小球作为去除阳离子染料的高效吸附剂：等温线，动力学和热力学研究

Activated Carbon/Chitosan Porous Beads as a High Efficiency Adsorbent for Cationic Dye Removal: Isotherm, Kinetic, and Thermodynamic Studies

摘要: 本文利用交联、固化和冷冻干燥的方法制备了活性炭/壳聚糖(AC/CHI)多孔小球，并研究了这种多孔小球对亚甲基蓝的吸附性能和吸附机制，采用扫描电子显微镜(SEM)和傅里叶变换红外光谱仪(FTIR)对多孔小球的表面形貌和化学结构性质进行表征分析，探究了溶液pH、接触时间、温度和吸附剂加入量等因素对AC/CHI多孔小球吸附亚甲基蓝的影响。实验结果表明，亚甲基蓝在AC/CHI多孔小球上的吸附平衡数据既符合朗缪尔模型，又符合弗伦德里希模型，通过计算得到的最大吸附量高达1194.33 mg/g。这表明AC/CHI多孔小球在去除污水中的染料方面有着很广阔的应用前景。吸附动力学研究显示准二级动力学模型能更准确的描述AC/CHI多孔小球对亚甲基蓝的吸附数据。热力学参数表明该吸附过程是自发的和吸热的过程。

Abstract: The activated carbon/chitosan (AC/CHI) composite porous beads were prepared by cross-linking, curing and freeze-drying methods and were used as an effective adsorbent for the removal of methylene blue (MB) from aqueous solution. The properties of the synthesized AC/CHI were characterized by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The effect factors including temperature, dosage, contact time, and pH on the adsorption properties of methylene blue onto AC/CHI were studied. The adsorption equilibrium data of methylene blue onto activated carbon were well fitted both to the Langmuir model and Freundlich model, giving a maximum adsorption capacity of 1194.33 mg/g. It indicates that AC/CHI is a promising adsorbent for removing methylene blue from aqueous solution. The kinetic data were well described by the pseudo-second-order model. Thermodynamic parameters indicate that ad-sorption process is spontaneous and endothermic.