用于高效去除水中孔雀石绿的三层结构磁性复合材料Fe3O4@聚丙烯酸@ZiF-8的制备

设计并合成了一种以磁性纳米粒子为核，聚合物为中间层，金属有机骨架材料为外层的三层结构磁性复合材料(Fe₃O₄@PAA@ZIF 8)。首先利用溶剂热法制备Fe₃O₄纳米粒子，然后通过蒸馏沉淀聚合法在Fe₃O₄纳米粒子表面包覆聚丙烯酸(PAA)层，最后通过原位沉积法在PAA外部包覆ZIF 8。在对Fe₃O₄@PAA@ZIF 8的组成和结构进行表征的基础上，深入研究其对孔雀石绿(MG)的吸附性能。透射电子显微镜(TEM)显示 Fe₃O₄@PAA@ZIF 8 具有明显的三层结构，Fe₃O₄的平均粒径为 117nm，PAA 层厚度约为 17 nm，ZIF 8层的厚度约为 14 nm。Fe₃O₄@PAA@ZIF 8对 MG 的吸附量随着 pH 的升高而增大，吸附过程符合准二阶动力学模型和 Langmuir等温吸附模型。此外，Fe₃O₄@PAA@ZIF 8还表现出良好的重复利用性能，8次循环利用后对MG(500 mg·L^-1)的最大吸附量仍可达982 mg·g^-1。

Preparation of three-layer magnetic composite Fe3O4@polyacrylic acid@ZiF-8 for efficient removal of malachite green in water

A magnetic composite material (Fe₃O₄@PAA@ZIF-8) was designed and synthesized with magnetic nanoparticles as the nucleus, polymer as the intermediate layer, and zeolitic imidazolate framework-8 (ZIF-8) as the outer layer. First, Fe₃O₄ nanoparticles were prepared by solvothermal method, and then polyacrylic acid (PAA) layer was coated on the surface of Fe₃O₄ nanoparticles by distillation precipitation polymerization, and finally ZIF-8 was coated on the surface of the Fe₃O₄@PAA by in-situ deposition method (composite method). Based on the characterization of the composition, structure and morphology of Fe₃O₄@PAA@ZIF-8, the adsorption properties of malachite green (MG) were studied in depth. Transmission electron microscope (TEM) showed that Fe₃O₄@PAA@ZIF-8 had a distinct three-layer structure, with an average particle size of 117 nm for Fe₃O₄, a thickness of about 17 nm for the PAA layer, and a thickness of about 14 nm for the ZIF-8 layer. The adsorption capacity of Fe₃O₄@PAA@ZIF-8 for MG increased with the increase of pH, and the adsorption process conformed to the quasi-second-order kinetic model and the Langmuir isothermal model, and the maximum adsorption capacity could reach 9 759 mg·g^-1. In addition, Fe₃O₄@PAA@ZIF-8 had good reusability, and the maximum adsorption capacity of MG (500 mg·L^-1) could still reach 982 mg·g^-1 after 8 cycles.