Catalytic degradation of methyl orange using biogenic nanosilver and its phytotoxicity evaluation

Abstract

The cell free extract of Staphylococcus aureus has been used to reduce the 1mM silver nitrate into silver nanoparticles (AgNPs) in biological manner. The colour change from yellowish to brown colour is primary confirmation of AgNPs synthesis. Further, the synthesized AgNPs have been characterized by UV-vis for confirmation of reduction process. The morphology of AgNPs is visualized using transmission electron microscope (TEM), selected area electron diffraction (SAED), scanning electron microscope (SEM) is used to determine the size and zeta potential of AgNPs. The X-ray powder diffraction (XRD) is confirmed the presence of silver and its structure and the Fourier transform infrared spectroscopy (FT-IR) is used to determine the functional group that actively involved in methyl orange (MO) degradation. For application of AgNPs, different concentration (10-200 µg/mL) of AgNPs has been used to degrade the different concentration (100-2000 µg/mL) of MO. Roughly, 62% of MO (2000 µg/mL) has been degraded after treated with 200µg/mL of AgNPs. Further, the degradation is confirmed using FT-IR analysis that show the AgNPs break down the N=N bond of MO and dispersed it. The treated dye further evaluated its phyototoxicity against Oryza sativa and the results indicate that the treated dye has less toxicity than untreated.