Evolution of gluconic acid capped paramagnetic iron oxide nanoparticles

Magnetic iron oxide nanomaterials are essential for many industrial, environmental and biomedical applications. While ferromagnetic and superparamagnetic iron oxide materials are known, paramagnetic iron oxide nanoparticles have not been significantly reported. In this study, we report the synthesis and characterization of the gluconic acid capped paramagnetic iron oxide nanoparticles (PIONs) using a simple green co-precipitation approach. The PIONs were characterized using Fourier Transform infrared spectroscopy, Scanning electron microscopy, X-ray diffractiometry, differential scanning calorimetry, thermogravimetry, Brunauer–Emmett–Teller (BET) and vibrating sample magnetometry (VSM). The material exhibited linear relationship between magnetization and the field, thus confirming its paramagnetic nature. Also, the as-synthesized PIONs showed a positive zeta potential (+29.7 mV), H2 type IV mesoporous characteristics (pore size = 3.09 nm) with a higher surface area (261.31 m²/g) than some materials in the literature. The as-synthesized material, exhibited potentials for catalysis, organic synthesis, adsorption, environmental remediation and magnetic resonance T₁ bio-imaging.