PREPARATION OF MAGNETIC/SILICA/QUARTERNARYCHITOSAN BY SOL-GEL METHOD AND ITS STABILITY IN VARIOUS pH MEDIUM

Abstract

This research aimed to study SiO2/quaternary-chitosan-coated magnetic material synthesis using the sol-gel method through two synthetic routes. The step of Route 1 was the methylation of the amine group on chitosan using methyl iodide and sodium hydroxide with dimethylformamide : water (1:1) as a solvent at room temperature for 48 hours to produce trimethyl chitosan. The next step was the sol-gel reaction. The magnetic was coated with silica and then added to the trimethyl chitosan solution that has reacted with (3-glycidyloxypropyl)trimethoxysilane as a crosslinker. Whereas Route 2 was the opposite of route 1, magnetic coating with chitosan silica was carried out first through the sol-gel reaction, followed by the methylation reaction. The synthesis results were characterized by their functional group, structure, crystal size, magnetic properties, and morphology. The Fe3O4/SiO2/quaternary-chitosan material was successfully synthesized, as indicated by the increase in the specific absorption band for C-H methyl and the decrease in the N-H amine absorption. Route 1 produced material with more quaternary ammonium groups and porous surface but inhomogeneous, while Route 2 produced thicker magnetic coatings. Both materials had stability in the range of pH 3-6 so that they could be applied as adsorbents for anionic compounds in this range.