Biosynthesis of silver nanoparticles as a reliable alternative for the catalytic degradation of organic dyes and antibacterial applications

Abstract

Water bodies are being threatened continuously by various anthropogenic pollutants such as organic dyes and bacteria which led to scarcity of fresh water suitable for drinking and irrigation. Therefore, different water treatment methods have been implemented before the discharge of contaminated wastewater into water bodies. In this report, green-synthesized silver nanoparticles (AgNPs) were evaluated in the degradation of organic dyes and bacterial decontamination. The S. costus root aqueous extract was used as an environmentally benign reducing agent in the biosynthesis of AgNPs. The synthetic procedure was optimized in terms of different parameters, and several analytical techniques were used to thoroughly characterize the prepared nanocomposites including TEM, SEM, EDX, DLS, XRD, FTIR, UV/Vis, photoluminescence, and TGA. The nanoparticles were spherical, monodisperse, colloidally and thermally stable, and crystalline in nature. The efficiency of the biogenic AgNPs as catalysts for the degradation of organic dyes was evaluated against six structurally diverse dyes. These included methylene blue, phenol red, methyl orange, Congo red, orange G and safranin O. Moreover, the applicability of AgNPs as antibacterial agents was tested against K. pneumoniae, S. aureus, S. haemolyticus and E. faecalis where the zones of growth inhibition, MIC and MBC values were determined for each bacterium. Overall, the biosynthesized nanoparticles were remarkable catalysts in the discoloration of hazardous dyes and displayed notable antibacterial potency against Gram-positive and Gram-negative bacteria.