论文部分内容阅读
采用静电自组装法制备了磁性纤维素纳米晶(MCNCs),使用Zeta电位测定仪、X射线衍射、综合物性测量系统等测试对MCNCs的形成机制、表面形貌、结构和磁性能进行表征,进一步研究了MCNCs对Pb~(2+)的吸附,探讨了溶液pH和Pb~(2+)初始浓度对其吸附性能的影响。结果表明,纤维素纳米晶(CNCs)与聚乙烯亚胺(PEI)修饰后带正电的Fe_3O_4纳米粒子(PEI-Fe_3O_4)之间的静电吸附是MCNCs形成的主要作用力,10~20nm的PEI-Fe_3O_4分散在CNCs表面,晶型结构没有改变,但两者的相互作用显著提高了MCNCs的热稳定性。MCNCs的饱和磁化强度达到30.9emu/g,可有效实现磁性分离。在pH=5.9,Pb~(2+)初始浓度大于600mg/L的条件下,对Pb~(2+)的最大吸附量可达103.7mg/g,吸附平衡时间为90min,拟一、二级动力学模型均能较好的拟合Pb~(2+)的吸附动力学数据,吸附由表面反应过程和非吸附质扩散过程控制,表面反应过程起主导作用。
Magnetic microcrystalline nanocrystals (MCNCs) were prepared by electrostatic self-assembly method. The formation mechanism, surface morphology, structure and magnetic properties of MCNCs were characterized by Zeta potential meter, X-ray diffraction and comprehensive physical property measurement system. The adsorption of Pb 2+ by MCNCs was studied. The effects of solution pH and the initial concentration of Pb 2+ on the adsorption of Pb 2+ were investigated. The results showed that the electrostatic interaction between CNCs and polyethyleneimine (PEI) modified Fe 3 O 4 nanoparticles (PEI-Fe 3 O 4) was the main force for the formation of MCNCs. PEI 10 ~ 20nm -Fe_3O_4 dispersed on the surface of CNCs, the crystal structure did not change, but the interaction between the two significantly increased the thermal stability of MCNCs. The saturation magnetization of MCNCs reaches 30.9 emu / g, which can effectively achieve magnetic separation. Under the conditions of pH = 5.9 and initial concentration of Pb2 +> 600mg / L, the maximum adsorption capacity of Pb2 + was 103.7mg / g and the adsorption equilibrium time was 90min. The kinetic model can well fit the Pb 2+ adsorption kinetics data. The adsorption is controlled by the surface reaction process and the non-adsorbate diffusion process, and the surface reaction process plays a leading role.