磁性Fe3O4纳米复合材料的制备及其对Pb(II)的吸附

为解决磁性纳米Fe₃O₄易被腐蚀、团聚等问题，可对其进行功能化修饰。在超声波辐照下首先制备磁性纳米Fe₃O₄颗粒，然后选用2,5-二氨基苯磺酸(SP)和间苯二胺(mPD)单体为引入剂进行功能化修饰，制备得到富含氨基、磺酸基和亚氨基活性官能团的金属基复合材料Fe3O4-mPD/SP(95∶5)，并采用FTIR、TEM、XRD等手段对其进行表征，证实了超声波辐照法制得的磁性纳米复合材料具有稳定性好、反应活性高、粒径小和比表面积更大等特点。同时考察其对Pb(II)的吸附性能，结果表明：mPD和SP摩尔比、溶液pH值、竞争性阳离子种类和反应温度等因素均会影响吸附效果；等温吸附过程符合Freundlich模型，吉布斯自由能?G0<0，吸附是一个自发过程；Pb(II)的吸附行为符合准二级动力学，速率常数k₂=3.61×10^-3 g·mg^-1·min^-1，平衡吸附量q_e=63.297 mg·g

Preparation of magnetic Fe3O4 nanocomposites and their adsorption to Pb(II)

In order to solve the problem that Fe₃O₄ nanoparticles were easy to be corroded and agglomerated, it was decided to functionalize it. Magnetic nano-Fe₃O₄ particles were prepared under ultrasonic irradiation, then 2-diaminobenzenesulfonic acid (SP) and m-phenylenediamine (mPD) monomers were selected as introduction agents to prepare metal matrix composites Fe₃O₄-mPD/SP(95∶5), which were rich in amino, sulfonic acid and imine active functional groups, and nanocomposites were characterized by FTIR, TEM, XRD and other methods. The characterized results show that the magnetic nanocomposites prepared by ultrasonic strengthening method have the characteristics of good stability, high reaction activity, small particle size and larger specific surface area. The adsorption properties of Pb(II) by Fe₃O₄-mPD/SP were investigated which showed that the molar percentage of SP and mPD, reaction temperature, sorts of competitive cations and the pH value of solution all had effect on the adsorption of Pb(II). The adsorption isotherm conforms to the Freundlich model, and the adsorption of Pb(II) is a spontaneous process, Gibbs free energy ?G0<0. It is found that the adsorption behavior of Pb(II) on nanocomposites can be well described by quasi secondary dynamics equation, kinetic constant k₂=3.61×10?3 g·mg?1·min?1, equilibrium adsorption capacity q_e=63.297 mg·g?1. It is speculated that the adsorption mechanism of this adsorbent includes ion exchange, complex adsorption and electrostatic adsorption.