氧化铁／石墨烯原位复合物对铬酸钾吸附性能研究

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

采用共沉淀法制备Fe3O4磁性纳米颗粒以及通过原位生长法制备Fe3O4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pH值对Fe3O4吸附性能的影响。结果表明，椭圆形颗粒的Fe3O4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pH=3．5条件下，以Fe3O4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251mg；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。

Fe3O4 magnetic nanoparticles and iron oxide/graphene oxide（RGO） composite were prepared by copreeipitation 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 charac- terized 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 Fe3OJRGO 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 Fe3 O4/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. Fe3 O4/RGO composite possessed good cycle performance, and its adsorption rate for potassium chromate decreased by 10% after recycle test six times.