聚合多巴胺包覆的磁性微球吸附Cr(Ⅵ)

POLYDOPAMINE COATED MAGNETIC MICROSPHERES FOR Cr(Ⅵ) REMOVAL THROUGH ADSORPTION

用聚合多巴胺(PDA)包覆溶剂热法制备Fe_3O_4磁性微球,得到Fe_3O_4@PDA复合材料,并采用红外光谱、扫描电镜、透射电镜对复合材料进行表征。同时,对Fe_3O_4@PDA吸附溶液中六价铬(Cr(Ⅵ))的性能进行研究,考察了溶液pH对其吸附性能的影响。结果表明:Fe_3O_4@PDA在溶液pH为3.0时对Cr(Ⅵ)有较好的吸附性能,其吸附动力学数据符合伪二级动力学方程,等温吸附符合Langmuir吸附模型,最大吸附容量达到108.8 mg/g,热力学实验计算出的吉布斯自由能为负值,表明Cr(Ⅵ)在Fe_3O_4@PDA的吸附为自发过程。

The magnetic microspheres Fe_3O_4 was prepared by using solvothermal method. Polydopamine was covered on Fe_3O_4through self-polymerization of dopamine to form Fe_3O_4 @ PDA composite. The structure of Fe_3O_4 @ PDA composite was characterized by FTIR, SEM, TEM. The adsorption properties of Fe_3O_4 @ PDA on Cr（VI） were evaluated. Experiments were carried out to investigate the effects of solution pH on adsorption. Results showed that the Fe_3O_4@ PDA adsorption of Cr （VI） had better adsorption performance in solution pH value of 3.0, and the pseudo-second order kinetic model was adopt to describe the kinetic data. The isotherm adsorption data fit the Langmuir model well, and the calculated maximum adsorption capacity was 108.8 mg/g. Gibbs free energy calculated from thermodynamics data was negative, which demonstrated that the adsorption of Cr（VI） on magneticFe_3O_4@ PDA was spontaneous process.