Controlling the Microstructural Properties of Magnetic Iron Oxide Synthesized using Brown Seaweed (Sargassum crassifolium) Extract

Magnetic nano- and microstructures are considered as significant materials for the development of advanced devices for various applications. In this paper, we present the synthesis of magnetic iron oxide microstructures via green-mediated chemical reduction technique and the effect of brown seaweed (Sargassum. crassifolium) extract on their microstructural properties. Ultraviolet-visible spectroscopy results confirmed the successful formation of magnetic iron oxide, while Fourier transform-infrared spectroscopy revealed the incorporation of the functional groups from the brown seaweed extract. X-ray diffraction has further shown that the samples were crystalline, and scanning electron microscopy showed the formation of irregular clusters with sizes ranging from 65 $\mu$ m to 390 $\mu$ m. Interestingly, the sizes of the microstructures were significantly reduced as the volume of the brown seaweed extract was increased, and a significant increase in the size distribution was observed. Finally, further inspection at a higher magnification revealed that the samples were composed of irregular nanostructures, and were confirmed by atomic force microscopy. This work provides new insights on controlling the properties of magnetic iron oxide using “green” and facile strategies.