磁性载镧鸡蛋壳对水中磷酸盐的吸附性能

Adsorption characteristics of magnetic lanthanum modified eggshell for phosphorus in water

摘要:

将镧离子和铁氧化物负载于鸡蛋壳(Eggshell，ES)上，获得一种易分离的除磷吸附剂：磁性载镧鸡蛋壳(Eggshell@Fe3O4-La，ES@Fe3O4-La)。采用X射线荧光光谱仪(XRF)、X射线衍射仪(XRD)、傅里叶变换红外光谱仪(FT-IR)和粒度分析仪对ES@Fe3O4-La结构进行表征，并研究ES@Fe3O4-La对水中磷的吸附特征。结果表明，与ES相比，ES@Fe3O4-La能够明显提高对磷酸盐的吸附能力，25℃条件下磷酸盐在ES上的最大吸附容量qmax为2.58 mg/g，而相同条件下磷酸盐在ES@Fe3O4-La上的最大吸附容量qmax为18.02mg/g。 ES@Fe3O4-La对磷的吸附是吸热过程，其吸附等温线符合Langmuir方程，吸附动力学过程遵循准二级反应动力学模型。磷溶液的初始pH 值对ES@Fe3O4-La吸附磷的影响较大，当 pH为3~4 时，ES@Fe3O4-La对磷的去除效果最佳。

Abstract:

An easily separated dephosphorization adsorbent, magnetic lanthanum-carrying eggshell (ES@Fe3O4-La) was obtained by loading lanthanum ions and iron oxides on the eggshell (ES). ES@Fe3O4-La was characterized by X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), Fourier transform infrared (FTIR) and laser particle size analyzer. The adsorption characteristics of ES@Fe3O4-La for phosphate in water were studied. The results showed that ES@Fe3O4-La had obviously higher adsorption capacity for phosphate than eggshell. The maximum adsorption capacity (qmax ) of ES@Fe3O4-La for phosphate was 18.02 mg/g at 25℃, while that on eggshell was only 2.58 mg/g. The phosphate adsorption on ES@Fe3O4-La was an endothermic process. The adsorption isotherm and kinetic data were well described by the Langmuir equation and the pseudo-second-order kinetic model. In addition, the initial pH value of phosphate solution had a great influence on the adsorption of phosphate on ES@Fe3O4-La. When pH was 3~4, ES@Fe3O4-La displayed the best removal effect of phosphate.