Core-shell Fe3O4/SiO2/TiO2 Magnetic Modified Ag for the Photocatalytic Degradation of Congo Red Dye and Antibacterial Activity

Abstract

Disposal of dye wastewater can induce detrimental consequences for human health and the environment. The study aims to synthesize composites consisting of core-shell Fe₃O₄/SiO₂/TiO₂ modified with Ag. The composites comprise a Fe₃O₄ core, a SiO₂ interlayer, and a TiO₂ shell, with Ag being mobilized on the surface of the core and shell structures. Fe₃O₄/SiO₂/TiO₂@Ag composite was employed in the photocatalytic degradation of Congo red dye and antibacterial activity test. The degradation was facilitated by visible light irradiation while considering different factors such as pH solution, the photocatalyst dosage, and the dye's initial concentration. The composite was characterized using X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy-Electron Dispersive X-ray Spectroscopy (SEM-EDS), Vibrating Sample Magnetometer (VSM), and UV-Vis Diffuse Reflectance Spectroscopy (UV-Vis DRS). The findings indicated that the composite exhibited strong magnetic, measuring 49.4 emu/g, with a band gap of 2.92 eV. The composite showed commendable catalytic properties, with degradation efficiency of 96.52% for Congo red dye under conditions: a pH solution of 4, a dosage of 0.5 g/L, and a dye concentration of 10 mg/L at 100 min of irradiation. The photocatalytic degradation kinetic is align with pseudo-first-order reactions. The composite also exhibits remarkable stability and efficiency with 4.83% decline in degradation efficiency after five cycles. Fe₃O₄/SiO₂/TiO₂@Ag composite exhibited antibacterial activity against Escherichia coli and Staphylococcus aureus with a Minimum Inhibitory Concentration (MIC) value of 250 mg/L.