聚多巴胺包覆的磁性碳纳米管对水中Ni^2+的吸附作用

Adsorption of Ni^2+from water by polydopamine-modified magnetic carbon nanotubes

以碳纳米管(MWNTs)、多巴胺、硫酸亚铁铵、硫酸铁铵为主要原材料,采用化学共沉淀法制备磁性碳纳米管(mMWNTs),通过多巴胺原位氧化聚合到磁性碳纳米管表面上,生成改性材料聚多巴胺(PDA)包覆的磁性碳纳米管(mMWNTs@PDA)。并采用红外光谱(FTIR)、扫描电镜(SEM)对其进行表征。考察了改性后材料在pH、反应时间、温度、初始浓度因素下对水中Ni^2+的吸附,同时对吸附数据进行吸附动力学和吸附等温线分析。结果表明,改性材料对水溶液中Ni^2+的吸附过程更符合准二级动力学模型(R^2=0.9989)和Freundlich等温吸附模型(R^2=0.9961)。最后考察改性材料的重复利用性能,实验结果证明经循环再生5次后仍然具有较好的吸附性能。

Carbon nanotubes(MWNTs),dopamine,ammonium ferrous sulfate and ammonium ferric sulfate are the main raw materials.Magnetic carbon nanotubes(mMWNTs)were prepared by chemical co-precipitation method,and dopamine-coated magnetic carbon nanotubes(mMWNTs@PDA)were obtained with in situ oxidative polymerization of dopamine onto the surface of magnetic carbon nanotubes.It was characterized by Fourier transform infrared spectroscopy and Scanning electron microscope.The adsorption performance of Ni^2+in water were investigated by modified materials under the conditions of pH,reaction time,temperature and initial concentration.At the same time,adsorption kinetics and adsorption isotherm were analyzed based on the adsorption data.The results showed that the adsorption process of Ni^2+in aqueous solution by modified materials was more in line with the pseudo-second-order kinetic model(R^2=0.9989)and Freundlich isotherm adsorption model(R^2=0.9961).Finally,the reusability of the modified material was investigated,and the experimental results showed that the modified material still had good adsorption property after recycling for 5 times.