Evaluation of photocatalytic degradation of Bisphenol A by reusable Fe3O4/SiO2/TiO2 magnetic nanocomposite: Optimization by response surface methodology

Abstract The removal of bisphenol A (BPA) as an estrogenic endocrine disrupting contaminant has recently been a topic of interest and debate among environmental scientists. In the present work, photodegradation of BPA in an aqueous solution was studied using Fe₃O₄/SiO₂/TiO₂ nanocomposite under ultraviolet A (UVA) and solar light sources. The as-synthesized materials were characterized by UV-Visible diffuse reflectance spectra (DRS), scanning electron microscope (SEM), Fourier transform infrared (FTIR), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM), zeta potential measurement techniques. Based on XRD and VSM, the Fe₃O₄/SiO₂/TiO₂ nanocomposite structure contained an anatase TiO₂ phase and showed a superparamagnetic behavior (12.07 emu/g). Based on the DRS spectra and bandgap computation, the direct bandgap energy of Fe₃O₄/SiO₂/TiO₂ was 3.01 eV. The Photocatalytic degradation of BPA was performed by the response surface methodology to study the influence of operational factors on the degradation process. Maximum removal of 55% BPA was obtained at a pH of 8, a photocatalyst dosage of 1.0 g/l, and a BPA concentration of 100 mg/l after 220 min UVA irradiation time. It is anticipated that the as-synthesized photocatalyst is expected to be used in both ultraviolet and solar light. The findings showed that Fe₃O₄/SiO₂/TiO₂ was recycled five times to attain 50% degradation of BPA and the photocatalytic activity did not decrease noticeably after five photocatalytic cycles. Furthermore, the ability to use solar energy, as well as the ease with which it may be implemented, makes photocatalysis an appealing possibility for the treatment of phenolic wastewater.