草鱼鱼鳞对金属离子的吸附性能及其机理

摘要

以草鱼鱼鳞为原料制备吸附剂,比较草鱼鱼鳞吸附剂对几种金属离子的吸附效果及其对Cu2＋的最佳吸附条件和相关影响因素,并通过Cu2＋吸附动力学和吸附热力学以及吸附前后的红外光谱分析,探讨鱼鳞吸附剂对Cu2＋的吸附机理。结果表明：草鱼鱼鳞对不同金属离子均具有良好的吸附能力,吸附效果依次为：Cu2＋〉Zn2＋〉Co2＋〉Mn2＋〉Cr2＋;在室温条件下,草鱼鱼鳞吸附Cu2＋的最佳吸附条件为：吸附剂用量1.25g/L、体系pH4、Cu2＋初始质量浓度为200μg/mL;吸附热力学和动力学分析表明,鱼鳞吸附剂对Cu2＋的吸附是一种包含化学吸附和物理吸附在内的多层吸附过程,升高温度有助于提高鱼鳞的吸附效果,准二级动力学模型可以较好地描述这种动态吸附行为。红外光谱分析表明,鱼鳞吸附剂中参与吸附Cu2＋的功能性官能团主要包括氨基、羧基、磷酸根和碳酸根等,其分别归属于鱼鳞中的蛋白质和羟基磷灰石类成分。%In this study,fish scale adsorbent was prepared from grass carp scales and comparatively investigated for its effectiveness in adsorbing several metal ions.The optimal conditions for Cu2+ adsorption by the adsorbent were studied and the mechanism of adsorption was explored by kinetic and thermodynamic analysis and infrared(IR) spectroscopy.The adsorbent had good adsorption capacity for different metal ions and its adsorption capacity followed the decreasing order: Cu2+ Zn2+ Co2+ Mn2+ Cr2+.The best adsorption results were obtained by using an adsorbent dose of 1.25 g/L to adsorb Cu2+ at an initial concentration of 200 μg/mL and pH 4 under room temperature conditions.Kinetic and thermodynamic analysis indicated that the adsorption of Cu2+ by the adsorbent was a multilayer process consisting of physical and chemical reactions and could be enhanced at higher temperatures,and the dynamic adsorption behavior could be well described by quasi-second-order kinetic model.IR spectroscopic analysis showed that the main functional groups in the fish scale adsorbent involved in adsorbing Cu2+ were amino,carboxyl,phosphate and carbonate groups,which were from rotein and hydroxyapatite,respectively.