Synergistic effect of novel biosynthesis SnO2@Fe3O4 nanocomposite: A comprehensive study of its photocatalytic of Dyes & antibiotics, antibacterial, and antimutagenic activities

Herein, we report that the biogenic Cassiterite SnO2@Fe3O4 nanocomposite (NC) was successfully synthesized using aqueous leaf extract of Laurus nobilis L. The indigenous population of Algeria frequently used this aromatic plant for both medicinal applications and as a spice source. The biosynthesis of SnO2@Fe3O4 NC was confirmed by the shift color from black to light peanut color and further confirmed by the UV–Visible spectrophotometry (UV–Vis). Scanning Electron Microscopy (SEM) confirmed the nanoscale of the NC 25–35 nm. X-Ray Diffraction (XRD) determined a tetragonal nature for SnO2 and orthorhombic for Fe3O4. The successful synthesis of green SnO2@Fe3O4 NC was verified through Fourier transformed infrared (FT-IR) spectroscopy, which detected the functional groups present in the composite.Interestingly, the SnO2@Fe3O4 NC showed excellent degradation of Rose Bengal/RB (96.7%), Methylene Blue/MB (88.3%), and Toluidine Blue/TB (96.5%) within a reaction period of 120 min at 10 ppm. The reaction kinetics followed the pseudo-first order and indicated rate constant (k) values 0.0244 min−1, 0.0263 min−1, and 0.0164 min−1 for RB, MB, and TB, respectively. The high dyes degradation rate assigned to the low band gap of NC that found to be 4.6 eV for indirect bandgap and direct bandgap 1.5 eV. Furthermore, SnO2@Fe3O4 NC exhibits an excellent degradation rate for Cephalexin /CEX (95%) and Amoxicillin /AMOX (88%) with rate constant 0.134 min−1 and 0.124 min−1 respectively. Also, the NC exerted a strong antibacterial activity at (1, 3, and 5 mM), particularly the 1 mM of NC showed the most effect against Escherichia coli (16 ± 1 mm), and in a lesser extent against Staphylococcus aureus (14 ± 0.5 mm) and Pseudomonas aeruginosa(13 ± 0.8 mm). Antimutagenic activity of the SnO2@Fe3O4 NC aqueous solution at (0–250 μg/tube) was assessed by the Salmonella micro-suspension experiment (YG1024 strain) and 1-nitropyrene (1-NP) (100 ng/tube) as the mutagen. The NC exhibit strong anti-mutagenicity against S. typhimurium TA98 and the percent inhibition was 78% at 250 µg/tube of SnO2@Fe3O4 NC.