Effect of Functionalized Magnetite Nanoparticles on the Structure and Thermal Stability of Magnetic Nanocomposites

Using magnetic and biodegradable polymers for removal of soluble pesticides can reduce environmental and human health damage caused by their presence in rivers, streams, and lakes. In this study, we develop and characterize the crystallinity and thermal properties of novel magnetic hydrogels based on polysaccharides, zeolites, and magnetite (Fe3O4) nanoparticles (NPs), and magnetic NPs (MNs) functionalized with 3-aminopropyltriethoxysilane (Fe3O4@NH2); these hydrogels are supported in reticulated networks of poly(methacrylic acid)-co-polyacrylamide. The potential of the hydrogel for herbicide removal, specifically removal of paraquat, is also investigated. The Fourier-transform infrared spectroscopy, X-ray diffraction analysis, thermogravimetric, kinetic, and swelling degree analysis results demonstrate that MNs do not affect these properties. However, minor changes, such as the peak at 2θ = 35.57º representing the (311) plane of Fe3O4, visible in the nanocomposite pattern with Fe3O4, confirm the incorporation of MNs into the polymer matrix. The adsorption results of paraquat through ultraviolet–visible spectroscopy measurements show a small difference in adsorptive capacity (qeq) between pure hydrogel (12.95 mg.g−1) and hydrogel with 2.0% functionalized Fe3O4 NPs (12.99 mg.g−1). Overall, incorporating Fe3O4 NPs in the hydrogel matrix yields materials with promising characteristics and while offering easier, safer removal from the environment.