磁性镁铝类水滑石的制备及其对甲基橙的吸附研究

摘要

采用液相非稳态共沉淀法制备了磁性镁铝类水滑石(Fe3O4@HTlc),通过透射电子显微镜、粉末X射线衍射仪、傅里叶变换红外光谱仪、振动样品磁强计、比表面分析仪、微电泳仪等对样品的形貌和结构进行了表征,并比较了Fe3O4@HTlc和HTlc对甲基橙的吸附性能.结果表明,Fe3O4@HTlc为顺磁性的具有核-壳结构和较大比表面积并带有正电荷的近球状颗粒.甲基橙在Fe3O4@HTlc和HTlc上的吸附动力学曲线均符合准一级动力学方程,吸附等温线均符合Langmuir吸附等温式;298K时Fe3O4@HTlc和HTlc对甲基橙的饱和吸附量分别为138.89和147.O6mg/g,且Fe3O4@HTlc对甲基橙有较强吸附推动力和较短的吸附平衡时间.二者对甲基橙的吸附量均随温度的升高和pH (5～11)的增加而降低.%Mg-A1 hydrotalcite-like compound (HTlc) and Fe3O4@HTlc were prepared by coprecipitation method.The phase identification and morphology of the HTlc and Fe3O4@HTlc were characterized by TEM,XRD,FTIR,VSM,N2 adsorption-desorption,and microiontophoresis apparatus.The adsorption performance of Fe3O4@HTlc and HTlc toward methyl orange(MO) was compared.The results showed that Fe3O4@HTlc particles were near spherical particles with paramagnetism,core-shell structures,larger specific surface areas and positive charges.The adsorption kinetics and adsorption isotherms of Fe3O4@HTlc and HTlc can be well described by the pseudo-first order kinetic and Langmuir isotherm.The saturated adsorption quantity of Fe3O4@HTlc and HTlc toward MO were 138.89mg/g and 147.06 mg/g,respectively,and Fe3O4@HTlc had a strong driving force toward MO and a shorter adsorption equilibrium time.The adsorption amounts of MO on both Fe3 O4@HTlc and HTlc decreased gradually with increasing temperature and increasing initial pH in the range of 5 ～ 11.