Enhanced Degradation of Safranin Dye Using Silver/Zinc Oxide Bimetallic Nanoparticles and Dye-Resistant Bacterial Strains from Contaminated Sites: A Comparative Study

Abstract

Chemically stable organic dyes like Safranin are less likely to be biodegradable and hardly get removed from wastewater through conventional treatment methods. The photocatalytic degradation and bacterial degradation of safranin dye were thoroughly investigated in this study. Four various bacteria isolated from dye-contaminated soil were used for decolourization. Those isolates were characterized and subjected to degraded Safranin at optimized conditions. This study aims to prepare unique, cheap, eco-friendly and bi-metallic Ag/ZnO NPs for the degradation of safranin dye, an important component in textile wastewater. In pursuit of this objective, bi-metallic Ag/ZnO nanoparticles were fabricated for the first time using Plectranthus amboinicus leaf extracts. The FT-IR spectra showed the role of the functional groups in P.amboinicus for the formation of Ag/ZnO NPs such as routine compounds. The synthesized PA-Ag/ZnO nanoparticles exhibited a zeta potential of − 16.4 mV, indicating high stability. The UV-visible spectrum showed absorption peaks at 204.81 and 216.73 nm wavelengths. The obtained PA-Ag/ZnO NPs were investigated as a nanocatalyst for safranin degradation. Its phytochemicals influenced the shape, size, stability, surface area, surface energy and photocatalytic activity. To confirm the formation of Ag/ZnO NPs, FT-IR, XRD, UV-Vis spectroscopy, zeta potential, SEM and TEM were performed. The photocatalytic degradation of Safranin by PA-Ag/ZnO nanoparticles was carried out at optimized conditions, and the degradation rate of 94% at 10mg concentration was observed. After optimizing degradation conditions, comparative degradation studies between the PA-Ag/ZnO nanoparticles and bacteria were performed using GC-MS analysis. These findings represent that synthesized Ag/ZnO nanoparticles using P. amboinicus will be used in wastewater treatment.

Graphical Abstract