磁性镍基氮掺杂多壁碳纳米管对双酚A的吸附性能及机理研究

Adsorption Performance and Mechanism of Ni-based Nitrogen-doped Magnetic Multi-wall Carbon Nanotubes for Bisphenol A

通过简单的高温煅烧法制备了具有较大比表面积的磁性镍基氮掺杂多壁碳纳米管材料(Ni-NMCNTs),将该材料用于双酚A(BPA)的吸附研究,对材料吸附前后的形貌和结构变化进行表征,探究其吸附机理。结果表明:具有中空管状结构的磁性Ni-NMCNTs对BPA具有良好的吸附能力和重复利用性,材料中吡啶氮的存在提供了吸附缺陷位且增强了π-π共轭作用,为提高吸附性能奠定了基础。实验发现酸性条件下更有利于Ni-NMCNTs对BPA的吸附,在室温25℃,投加量20 mg,pH 6.0条件下,最大吸附容量可达83.64 mg/g,15 min内BPA的吸附率可达86.8%。吸附过程符合准二级动力学方程和Freundlich吸附等温线模型,热力学参数表明整个过程自发进行。

A kind of magnetic Ni-based N-doped multi-walled carbon nanotubes(Ni-NMCNTs),with large specific surface area,were prepared by high temperature calcination.The morphology and structural changes of the material before and after adsorption were characterized,and its adsorption mechanism was further explored.Results showed that this magnetic Ni-NMCNTs with hollow tubular structure exhibited good adsorption capacity and reusability for BPA,and the presence of pyridine nitrogen in the material provided adsorption defect sites and enhancedπ-πconjugation,which layed the foundation for improving adsorption performance.Experiments showed that acidic conditions are more conducive to the adsorption of BPA by Ni-NMCNTs.At ambient 25℃conditions,the maximum adsorption capacity could reach 83.64 mg/g and the adsorption percentage of BPA could reach up to 86.8%in 15 min when the dosage was 20 mg and pH value was 6.0.The adsorption process was in general agreement with the pseudo-second order kinetic equation and Freundlich adsorption isotherm model.The thermodynamic parameters demonstrated that the whole adsorption process was spontaneous.