Effect of synthetic conditions on the crystallinity, porosity and magnetic properties of gluconic acid capped iron oxide nanoparticles

Magnetic iron oxide nanoparticles are essential materials for the molecular separation process, catalysis, drug-delivery and water remediation. In this paper, the effect of synthesis conditions on the characteristic crystallinity, porosity and magnetic properties of gluconic acid capped iron oxide nanoparticles were evaluated. The iron oxide nanomaterials were synthesized using the coprecipitation method and characterized using Fourier Transform Infrared spectroscopy (FTIR), scanning electron microscopy (SEM), x-ray diffraction (XRD), superconducting quantum interference device (SQUID) and Brunauer–Emmett–Teller (BET) techniques. The SQUID results showed that the as-synthesized nanomaterials possessed both paramagnetic and superparamagnetic properties with saturation magnetization (Ms) values ranging between 1.49 and 2.69 emu/g. Textural analysis revealed that the nanomaterials were mesoporous in nature with Type II isotherm and H3 hysteresis loop and Type IV isotherm with H2 hysteresis loop respectively. XRD analyses showed the nanomaterials to be maghemites and haematite with average crystallite sizes ranging from 10.85 to 16.27 nm. Also, the nanomaterials exhibited high surface areas ranging from 158.54 to 353.80 m²/g and pore size ranged between 3.33 and 5.54 nm. This information suggests that iron oxide nanomaterials with different porosity, crystallinity, and magnetic properties may be obtained by varying the synthesis conditions.