铁酸盐-还原石墨烯复合材料的制备及其对亚甲基蓝的吸附

以氯化铁(FeCl3·6H2O)、氯化锰(MnCl2·4H2O)、氯化锌(ZnCl2)、氯化钴(CoCl2·6H2O)、氯化镍(NiCl2·6H2O)和氧化石墨烯(GO)为原料,制备了4种铁酸盐与还原氧化石墨烯(RGO)的复合材料(RGO-MFe2O4,M=Mn,Zn,Co或Ni),通过扫描电子显微镜、X-射线衍射仪、拉曼光谱仪进行了表征,系统研究了4种材料对亚甲基蓝的吸附。结果发现,RGO-NiFe2O4对亚甲基蓝的吸附能力最好,而对吸附起主要作用的是RGO。随着温度升高、染料初始浓度的增加和吸附时间的延长,RGO-NiFe2O4吸附量逐渐增大。RGO-NiFe2O4对亚甲基蓝的吸附动力学拟合符合伪二级动力学模型。吸附等温线模型拟合结果表明,Langmuir方程可以很好地描述其对亚甲基蓝的吸附。热力学参数ΔG0在不同温度下均为负值,ΔH0为正值,ΔS0为正值说明吸附过程是自发的吸热反应。

Preparation of magnetic reduced graphene oxide-ferrite hybrids and its adsorption of methylene blue

Magnetic reduced graphene oxide-ferrite hybrids(RGO-MFe2O4,where M=Mn,Zn,Co,or Ni) were prepared from FeCl3·6H2O,MnCl2·4H2O,ZnCl2,CoCl2·6H2O,NiCl2·6H2O,and graphene oxide(GO).The hybrids were characterized using scanning electron microscopy(SEM),X-ray diffraction(XRD),and Raman spectroscopy,and their methylene blue adsorption was systematically studied.RGO played a major role in the adsorption of methylene blue,and results indicated that RGO-NiFe2O4 had the highest adsorption capacity.A greater degree of adsorption was observed with increasing temperature as the initial concentration of methylene blue rose over time.The adsorption kinetics followed a pseudo-second-order kinetic equation,and a methylene blue adsorption isotherm was fitted using a Langmuir model.The adsorption process was determined to be spontaneous and exothermic,owing to thermodynamic parameters of negative ΔG0 and positive ΔH0 and ΔS0.