氧化铁/石墨烯原位复合物对铬酸钾吸附性能研究

采用共沉淀法制备Fe_3O_4磁性纳米颗粒以及通过原位生长法制备Fe_3O_4与氧化石墨烯的复合物,并加入十六烷基三甲基溴化铵形成共价键交联反应化合物。采用X射线衍射仪和透射电子显微镜表征样品的形貌与尺寸,并以铬酸钾为吸附对象,研究吸附温度、吸附时间和溶液p H值对Fe_3O_4吸附性能的影响。结果表明,椭圆形颗粒的Fe_3O_4尺寸约(10~15)nm,与氧化石墨烯复合后,分散性明显提高;在室温和p H=3.5条件下,以Fe_3O_4与氧化石墨烯的质量比2∶1复合物作为吸附剂对铬酸钾的吸附效果达到最佳,每克的吸附容量可达251 mg;复合物经过磁分离、反复吸附循环实验6次后,对铬酸钾的吸附率仅下降10个百分点。

Research on adsorption properties for iron oxide/graphene composite for potassium chromate

Fe₃O₄ magnetic nanoparticles and iron oxide/graphene oxide(RGO) composite were prepared by coprecipitation method and in-situ growth method,respectively.The as-prepared Fe3O4 nanoparticles and Fe₃O₄/RGO composite were modified by CTAB.The as-prepared Fe₃O₄/RGO composite was characterized by X-ray diffraction and transmission electron microscopy.The influence of reaction temperatures,reaction time,pH value of the solution,etc on adsorption properties of Fe₃O₄ and Fe₃O₄/RGO composite for potassium chromate was investigated.The results showed that adsorption reaction was exothermic,and the lower the temperature,the better the adsorption.The size of oval shaped particles Fe₃O₄ was about (10-15) nm and the dispersion of Fe₃O₄/RGO composite was obviously enhanced.Under the condition of pH value 3.5,room temperature and the mass ratio of Fe₃O₄/RGO 2∶1, the optimum adsorption capacity of Fe₃O₄/RGO composite reached 251 mg·g^-1.Fe3O4/RGO composite possessed good cycle performance,and its adsorption rate for potassium chromate decreased by 10% after recycle test six times.