Characterization of Silica-coated Fe₃O₄ Prepared Using Electrooxidation Method under Various Silica Source Concentration and Its Application for Thermoresponsive Polymer Immobilization

Abstract

The objectives of this study are 1) to investigate the effect of silica source concentration on the properties of the silica-coated magnetite nanoparticle (MNP) prepared using the electrooxidation method, and (2) to apply the resulting silica-coated MNP for the immobilization of thermoresponsive copolymer, (poly(NIPAM-co-AA)), which we developed for heavy metal ion recovery. The results of laser diffraction analysis show that the particle size distributions of the silica-coated MNP are smaller than that of the uncoated MNP, which indicates that the aggregation of MNP is suppressed by silica coating. Thermogravimetric analysis (TGA) results show that the immobilized copolymer amount on the silica-coated MNP is approximately 5 times larger than that on the uncoated MNP. These results indicate that the successful suppression of MNP aggregation through silica coating using the electrooxidation method contributes to the increase of the available surface area for the copolymer immobilization.