在四氧化三铁表面采用原位化学氧化合成了磁性聚吡咯(Ppy/Fe3O4)吸附剂,并用FTIR、XRD、TGA、XPS以及VSM等对材料进行表征.结果表明,聚吡咯成功包覆到Fe3O4表面,且具有超顺磁性.吸附实验结果表明,Ppy/Fe3O4对水中硝酸盐(NO3-)具有较好的吸附性能,在NO3-初始浓度为50 mg·L-1条件下,当pH值为4.2时,温度为25℃下吸附剂对NO3-的吸附效果最佳,最佳吸附量为37.57 mg·g-1,阴离子的存在对NO3-吸附具有抑制作用.Ppy/Fe3O4对NO3-的吸附可以通过Langmuir模型很好地描述,吸附过程服从拟二级动力学,并且吸附速率随着NO3-初始浓度的增加而增加.磁性聚吡咯通过表面质子化氮与NO3-之间的静电作用而达到去除的目的.吸附饱和的吸附剂可以很好地进行磁性分离,并可以在0.01 mol·L-1的NaCl溶液中进行脱附再生.
A magnetic polypyrrole(Ppy/Fe3O4) adsorbent was prepared by in situ chemical oxidative polymerization of pyrrole on the surface of Fe3O4,and characterized by FTIR,X-ray powder diffraction,thermal gravimetric analysis,X-ray photoelectron spectrometry and vibrating sample magnetometer. The results show that Ppy was successfully coated on the surface of Fe3O4,and Ppy/Fe3O4 is superparamagnetic. Adsorption tests of NO3-on Ppy/Fe3O4 showed that the optimum adsorption capacity of NO3-on the adsorbent was 37.57 mg·g-1at pH 4.2 and initial NO3-concentration of 50 mg·L-1,and the presence of anions decreased NO3-adsorption. NO3-adsorption on Ppy/Fe3O4 could be well described by the Langmuir model. The adsorption process obeyed pseudo-second-order kinetics, and the adsorption rate increased with increasing initial NO3-concentration. Adsorption of NO3-on Ppy/Fe3O4 was attributed to electrostatic interaction between NO3-and protonated nitrogen on the surface of Ppy. NO3-loaded adsorbent could be readily separated magnetically,and regenerated in 0.01 mol·L-1 NaCl solution.