Photocatalytic degradation of rhodamine B dye pollutants by Fe3O4/SiO2 core-shell magnetic nanocomposite functionalized with TiO2.

ABSTRACT

Significant efforts have been dedicated to creating recyclable and efficient methods for treating waste dyes, including rhodamine B (RhB). Nevertheless, challenges such as complex operational techniques, high costs, energy consumption, and inefficacy in dye removal persist. Here, the synthesis and application of TiO2/Fe3O4/SiO2 for photocatalytic degradation of RhB dye pollutants have been explored. This research was initiated with magnetite (Fe3O4) synthesis using the coprecipitation method, followed by silica (SiO2) extraction from rice husk waste using the sol-gel process, and a hydrothermal method for synthesizing titanium dioxide (TiO2) and TiO2/Fe3O4/SiO2 nanocomposite. The crystalline structure of TiO2/Fe3O4/SiO2 was obtained with Fe3O4 as the core, while TiO2 and SiO2 as the shell. The particle size analysis showed the nanosize of TiO2/Fe3O4/SiO2 (1.04 ± 0.46 nm). TiO2/Fe3O4/SiO2 nanocomposite boasts a high surface area of 48.025 m2/g, 2.2 times higher than unmodified TiO2. This nanocomposite also displayed paramagnetic properties with a saturation magnetization of 9.117 emu/g, facilitating easy separation in photocatalytic applications. The photocatalytic activity of TiO2/Fe3O4/SiO2 exhibited effectively degraded RhB, achieving a degradation rate of 53.58% and an excellent rate constant of 0.7303 min-1. The RhB photodegradation in this study requires a moderate irradiation time (60 min), uses only a tiny amount of photocatalyst (100 mg), and does not need additional chemicals. Moreover, this study has another advantage of utilizing rice husk as a silica source, offering an eco-friendly and sustainable approach.