Biosynthesis and characterization of zinc oxide nanoparticles using bioflocculant produced by a consortium of two marine bacteria

Abstract

Zinc oxide (ZnO) nanoparticles have acquired ubiquitous attentiveness owing to their distinctive features, making them appropriate for a diversity of applications in many fields of life science. Green synthesis approach for nanoparticles has garnered substantial interest due to their immanent characteristics which include swiftness, costeffectiveness and eco-friendliness as an alternative to the existing techniques. In this study, a bioflocculant, produced by the consortium of two bacteria namely Bacillus safensis and Bacillus sp. was utilized as a reducing and stabilizing agent in the green synthesis of zinc oxide nanoparticles. The synthesized zinc oxide nanoparticles were characterized using Scanning electron microscope (SEM), UV-Visible spectroscopy (UV-Vis), Thermogravimetric analysis (TGA), Transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). UV-Vis spectroscopy revealed the absorption peaks to be around 300 - 330 nm which confirms the synthesis of zinc oxide nanoparticles. Elements such as Al, C, P, O and Zn were found in the as-synthesized nanomaterials with 30.01% wt of oxygen and 39.15% wt of zinc as revealed by the SEMEDX technique. TEM and SEM images of the product give information on the morphology which is spherical and agglomerated. XRD pattern of the synthesized nanoparticles shows that the substances belong to ZnO as no other diffraction peaks were observed matching that of JCPDS card for ZnO. The average crystallite size of the particles was estimated to be 24.66 nm from XRD pattern. FT-IR spectrum of the biosynthesized nanomaterials shows Zn-O functional group at low wavenumber (473 cm-1). Therefore, the bioflocculantmediated synthesis of nanoparticles can be considered as environmental benign greener approach.