铁矿渣磁性纳米颗粒的制备及其对Pb(Ⅱ)和Cd(Ⅱ)的吸附潜力

Preparation and Pb(Ⅱ)and Cd(Ⅱ)adsorption potential of magnetic nanoparticles from iron slag

【目的】制备铁矿渣磁性纳米颗粒,研究其对Pb(Ⅱ)和Cd(Ⅱ)的吸附性能,促进富含铁的工业固体废弃物的资源化利用。【方法】以铁矿尾矿渣为原料,通过化学方法制备改性磁铁纳米颗粒3NH_2-SiO_2@Fe_3O_4,对其进行表征,以批处理法探讨了不同pH、Cd(Ⅱ)和Pb(Ⅱ)平衡质量浓度和吸附时间下3NH_2-SiO_2@Fe_3O_4对水体中Cd(Ⅱ)和Pb(Ⅱ)的吸附潜力,并用X射线光电子能谱分析技术对吸附Pb(Ⅱ)和Cd(Ⅱ)前后3NH_2-SiO_2@Fe_3O_4的结构进行分析。【结果】成功制备出了化学稳定性良好、粒径为73~160nm的磁性颗粒3NH_2-SiO_2@Fe_3O_4,磁化强度23.1emu/g,颗粒表面富含-NH_2官能团。随体系pH以及Pb(Ⅱ)和Cd(Ⅱ)平衡质量浓度的升高,3NH_2-SiO_2@Fe_3O_4对Pb(Ⅱ)和Cd(Ⅱ)的吸附量总体呈先迅速增加之后趋于平衡。在0~60min时,随着吸附时间的延长,3NH_2-SiO_2@Fe_3O_4对Pb(Ⅱ)和Cd(Ⅱ)吸附量迅速增加,120min后达到吸附平衡,准二级动力学模型能较好地拟合这一过程。Langmuir吸附等温模型能较好地拟合3NH_2-SiO_2@Fe_3O_4对Pb(Ⅱ)和Cd(Ⅱ)的吸附过程,3NH_2-SiO_2@Fe_3O_4对Pb(Ⅱ)和Cd(Ⅱ)的最大吸附量分别为158.86和88.93 mg/g。3NH_2-SiO_2@Fe_3O_4对Pb(Ⅱ)和Cd(Ⅱ)的吸附机制为不饱和配合吸附。【结论】以铁矿渣等含铁的工业固体废弃物为原料,成功制备出了对Pb(Ⅱ)和Cd(Ⅱ)具有较好吸附能力的磁性纳米颗粒3NH_2-SiO_2@Fe_3O_4。

【Objective】The Pb（Ⅱ）and Cd（Ⅱ）adsorption potentials of magnetic nanoparticles prepared from iron slag were investigated to improve the utilization of iron-rich industrial solid waste.【Method】Core-shell structured magnetic 3NH_2-SiO_2@Fe_3O_4particles were prepared using iron slag by chemical method.The effects of parameters including pH,Pb（Ⅱ）and Cd（Ⅱ）equilibrium mass concentrations,and contact time on adsorption performance were tested by batch experiments.The 3NH_2-SiO_2@Fe_3O_4particles before and after Pb（Ⅱ）and Cd（Ⅱ）adsorption were also analyzed by using X-ray photoelectron spectroscopy.【Result】Highly core-shell structured magnetic 3NH_2-SiO_2 @Fe_3O_4 particles with diameter of73-160 nm and magnetic power of around 23.1emu/g were obtained.The surface was grafted by plenty of amino-groups.With the increase of solution pH,Pb（Ⅱ）and Cd（Ⅱ）equilibrium mass concentrations,Pb（Ⅱ）and Cd（Ⅱ）adsorption amounts gradually increased and reached balance.The Pb（Ⅱ）and Cd（Ⅱ）adsorption amounts increased quickly within 60 min,and gradually kept unchanged after 120 min.The pseudo-second-order equation well fitted Pb（Ⅱ）and Cd（Ⅱ）adsorption kinetics process.Langmuir model could be used to describe the Pb（Ⅱ）and Cd（Ⅱ）adsorption onto 3NH_2-SiO_2 @Fe_3O_4 particle with the maximum adsorption capacities of 158.86mg/g for Pb（Ⅱ）and 88.93mg/g for Cd（Ⅱ）,respectively.The X-ray photoelectron spectroscopy analysis showed that Pb（Ⅱ）and Cd（Ⅱ）were adsorbed onto 3NH_2-SiO_2@Fe_3O_4surface through unsaturated complex reaction process.【Conclusion】Iron-rich industrial solid waste such as iron slag could be used for preparation of magnetic 3NH_2-SiO_2@Fe_3O_4particles with acceptable Pb（Ⅱ）and Cd（Ⅱ）adsorption ability.