Utilizing the iron tolerance potential of Bacillus species for biogenic synthesis of magnetite with visible light...

Recently, nanomaterial mediated degradation of water polluting industrial pollutant and dyes has become a topic of great interest. This study demonstrates enrichment, isolation, screening and molecular identification of iron tolerant Bacillus species for biosynthesis of iron oxide magnetic nanoparticles (IOMNPs). Synthesis parameters such as 5 mM FeCl_3, 7 days of static incubation at 37 °C and slightly alkaline pH range of 7-7.5 were the most optimum conditions. The spectroscopic and imaging studies demonstrated inverse spinel face-centered cubic structure of magnetite with average size of 81.3 nm, polydispersity of 0.343 and zeta potential of -42.49 mV. The specific saturation magnetization value and coercivity Hc of hysteresis loop of 28.1 emu/g and 5.8 Oe respectively confirmed the super-paramagnetic nature of IOMNPs. The comparison of phtotocatalytic activities under UV and visible light irradiation for degrdation of methyl violet, methylene blue, and rhodamine-B indicated that IOMNPs were visible light active photocatalysts. The study of effects of various reaction parameters indicated that catalyst loadings of 500-600 μg/mL, pH 7 and 20 μg/mL initial dye concetration were optimum conditions and reactions at these parameters were also observed to follow pseudo first order kinetics. This study successfully demonstrated the use of iron tolerant bacterium for visible light active, photocatalyst synthesis.