Fabrication of Fe3O4@poly(methyl methacrylate-co-glycidyl methacrylate) microspheres via miniemulsion polymerization using porous microspheres as templates for removal of cationic dyes

Abstract

Magnetic polymer microspheres have been widely used in nucleic acid extraction, immunoassays, drug screening, compound identification, wastewater treatment and catalysis. However, the particle size and magnetic material content of magnetic polymer microspheres prepared by miniemulsion polymerization cannot be effectively controlled. In this work, the porous polymer microspheres prepared by the two-step seed swelling polymerization method were used as templates. Based on it, the miniemulsion polymerization of magnetic fluid was performed to obtain magnetic Fe₃O₄@poly(methyl methacrylate-co-glycidyl methacrylate) (Fe₃O₄@P(MMA-co-GMA)) microspheres. TEM images showed that the magnetic Fe₃O₄@P(MMA-co-GMA) microspheres had diffuse structures. The magnetic material was scattered throughout the inside of the porous template polymer microspheres, and at the same time, polymer encapsulation of the magnetic material and functional modification of the surfaces for magnetic polymer microspheres were realized. Compared with the traditional template method, the method simplified the synthesis process, turning multiple steps into one step. Magnetic polymer microspheres with narrow particle size distribution, high magnetic material content, and different functionalized surfaces were prepared by this method. The magnetic Fe₃O₄@P(MMA-co-GMA) microspheres could be used to adsorb cationic dyes quickly and effectively. The results demonstrated that the maximum adsorption capacity for Nile blue was ∼109.4 mg g⁻¹, and the maximum dye removal efficiency could reach 99.9%. In addition, Fe₃O₄@P(MMA-co-GMA) microspheres exhibited good stability and recyclability for Nile blue removal over seven cycles. Therefore, this work proposed a novel and facile strategy to prepare magnetic polymer microspheres, which exhibited a significant potential application value in many fields.