Preparation of PEI Modified Magnetic Chitosan Microspheres and Their Adsorption Property for Ibuprofen

Magnetic Fe₃O₄ nano-particles were prepared by chemical coprecipitation method, and magnetic chitosan microspheres (Fe₃O₄@CS) and polyethyleneimine (PEI) modified magnetic chitosan microspheres (Fe₃O₄@CS/PEI) with different proportions were thereby prepared by Schiff base reaction in the emulsion system using glutaraldehyde as the crosslinking agent. The structure, particle size and magnetism of microspheres were characterized by infrared spectroscopy (FT-IR), X-ray powder diffraction(XRD), scanning electron microscope (SEM), dynamic laser scatter (DLS) and hysteresis loop. The adsorption amount of ibuprofen on microspheres and reuse rate were studied by ultraviolet spectrophotometer. The characterization results showed that the microspheres were successfully prepared by Schiff base reaction, which had no effect on the crystal phase of Fe₃O₄. The microspheres presented regular circle with narrow size distribution and they were magnetic. The thermodynamics adsorption model of ibuprofen on microspheres was Langmuir adsorption isotherm, and the kinetic adsorption model was second order dynamics model. With the increase of PEI mass fraction, the adsorption amount of ibuprofen on microspheres were increased. When m(PEI)∶m(CS)=1∶1, the maximum adsorption amount of ibuprofen on CP-3(Fe₃O₄@CS/PEI) was determined to be 138.63 mg/g by the Langmuir adsorption equation fitting, which was twice higher than that on CP-0(Fe₃O₄@CS). After repeating adsorption experiments for 5 times, the microspheres still showed good adsorption performance for ibuprofen.