Multifunctional Fe3O4-ZnO nanocomposites for environmental remediation applications

We developed a synthesis route for multifunctional (ZnO-Fe<inf>3</inf>O<inf>4</inf>) nanocomposites. The Fe<inf>3</inf>O<inf>4</inf> nanoparticles were decorated on the surface of ZnO and the formation of ZnO-Fe<inf>3</inf>O<inf>4</inf> (ZF) nanocomposite was confirmed using XRD, FE-SEM and ICP-OES. This work comprises of adsorption, photocatalysis and antibacterial studies. Photocatalytic property of ZF nanocomposite was tested using degradation of methylene blue (MB) dye under UV irradiation. It was observed that 50 ppm of ZF nanocomposite was able to remove 89.2% of the dye after 3 h of treatment. Adsorption efficiency of ZF nanocomposite was studied using adsorption of Pb²⁺ and Cu²⁺ metal ions (at pH 5.5) on the surface of ZF nanocomposite due to its high surface area. Antibacterial activity of ZF nanocomposite against E. coli and S. aureus was also tested and the nanocomposites showed efficient antimicrobial efficacy. The obtained multifunctional ZF nanocomposite demonstrated promising application in simultaneous removal of heavy metal ions, organic dye and bacterial pathogens, which can also be separated by magnet and can be reused multiple times. The results with ZF composites pave way to tailor the composition of the nano ZF composite adsorbent to tackle site-specific contamination.