改性鸡蛋壳对水中Pb^(2+)的吸附机理研究

Study on the adsorption mechanism of modified eggshell for Pb^(2+) removel in water

制备了一种新型吸附剂——硫酸铁改性鸡蛋壳表面结构,利用扫描电镜、X荧光光谱、X射线衍射分析及X射线光电子能谱等手段对该吸附剂表面结构进行表征。结果表明,在鸡蛋壳的表面存在水合氧化铁,从而增加了吸附位点,增加了其对于Pb^(2+)的吸附效果。改性鸡蛋壳对Pb^(2+)的吸附机理通过模拟吸附一阶动力学模型和吸附等温线发现,其更加符合Langmuir单分子层吸附机制。改性鸡蛋壳对Pb^(2+)的吸附量可以翻倍,高达90.919mg/g,说明这种新型吸附剂的吸附效果较好。溶液pH值和添加吸附剂的含量对这种吸附剂吸附Pb^(2+)过程也有很大的影响,但是离子强度对其影响较小。因此,改性鸡蛋壳是一种有潜在应用价值的二次利用吸附材料。

In this study,Fe2（SO4）3 modified eggshell（F/ES）was prepared for Pb（2＋） removal.The results of scanning electron microscopy（SEM）,X-ray fluorescence spectroscopy（EDS）,X-ray diffraction（XRD）and X-ray photoelectron spectroscopy（XPS）demonstrated that iron oxides hydrate was loaded onto the surfaces of eggshell,so that the adsorption sites and adsorption capacity both increased.The nonlinear fitting results of adsorption kinetics and isotherms demonstrated that the adsorption process was better fitted by first-order model than second-order model,and the adsorption mechanism was controlled by monolayer adsorption mechanism.The maximum Pb（2＋） adsorption capacity by F/ES was 90.919mg/g,which proved that the adsorption efficiency was enhanced by Fe2（SO4）3 modification.Solution pH and dosage influenced the adsorption process on Pb（2＋） removal by F/ES,while ionic strength slightly affected the adsorption process.Therefore,modified eggshell is a secondary adsorption material with potential applications.