Photocatalysis of Ag Nanoparticles in Wastewater Teatment

Nanomaterials are a remarkable innovation in the 21^st century for humanity. Environmental pollution is a great challenge for human civilization. Water pollution is the main threat to surviving. Much wastage is drained off to the water bodies, causing detrimental effects on aquatic life. The development of an innovative and novel technique to remediate water pollutants and make water safe for drinking is very necessary. Traditional methods have disadvantages of high pressure, temperature, cost, longer time, larger area, production of byproducts, etc. Photocatalysis in the presence of nanoparticles is the most remarkable method in wastewater treatment due to its cost-effective, simple, and eco-friendly nature. Nanoparticles possess large surface-to-volume ratio and extra-small-size NPs, and these properties make them applicable in scavenging organic pollutants within a short period to a larger extent. Ag nanoparticles (NPs) were synthesized using the plant extracts of Phragmites australis as reducing and capping agents. Ag NPs possessed superior photocatalytic properties in the scavenging of organic pollutants. To confirm the shape, size, optical properties, stability, and involvement of phytochemicals in the synthesis and stabilization of NPs, Transmission Electron Microscope (TEM), Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD), UV-Visible, Dynamic Light Scattering (DLS), Zeta potential and Fourier Transform Infrared (FTIR) analysis were performed, respectively. Photo-degradation of harmful dyes was carried out in presence of Ag NPs under sunlight. Ag NPs degraded Phenol Red (PR) and Brilliant Blue (BB) dyes up to 80%. Ag NPs efficiently inhibited the growth of human pathogens like Staphylococcus aureus and Escherichia coli. ZnO NPs also showed potential antioxidant activity in the DPPH assay. Hence, Phragmites australis fabricated Ag NPs (PA@ZnO NPs) will be novel innovative multifunctional materials for the treatment of wastewater for safe drinking water and prevention of transmission of severe contagious diseases like COVID-19.