Covalently Bonded Poly(Acrylic Acid)-Fe₃O₄ Nanocomposite Prepared in Supercritical CO₂ and Its Adsorption Capacity for Methylene Blue

Abstract

The surface of pristine Fe₃O₄ nanoparticles is first modified with a silane coupling agent methacryloxypropyltrimethoxysilane (MPTMS), which provides a reactive C = C bond to copolymerize with acrylic acid (AA) by in situ polymerization in scCO₂, resulting in the formation of covalently bonded PAA–Fe₃O₄ nanocomposite. The as-synthesized products were characterized using FT-IR, TGA, XRD, SEM, TEM, and XPS. The results indicated that the obtained nanocomposite had a core-shell structure, in which the Fe₃O₄ nanoparticle cores were coated completely with PAA shells. The adsorption of methylene blue onto the obtained nanocomposite increased with increasing solution pH.

Keywords:

• dye adsorption
• magnetite nanoparticles
• poly(acrylic acid)
• supercritical carbon dioxide

Acknowledgments

This research was supported by grant number RT104-01-04 from the Regional Technology Innovation Program of the Ministry of Knowledge and Economy (MOKE).