Photocatalytic and Catalytic Methods for Organic Azo Dyes and Paranitrophenol Pollutants Removal Using Green Synthesised Flacourtia indica Silver Nanoparticles

The advancement of photocatalytic nanomaterials has become central to addressing the growing challenge of removing organic pollutants from water systems through sustainable and efficient degradation pathways. In this study, silver nanoparticles were synthesized via a green approach using aqueous extracts derived from five parts of Flacourtia indica, including bark, flower, fruit, seed, and leaves, at 90°C for 45 minutes. UV–VIS spectroscopy (460 nm) confirmed nanoparticle formation, while scanning electron microscope analysis revealed predominantly spherical AgNP with diameters of 50 nm - 70 nm and semiconductor-like band-gap energy. This eco-friendly, non-toxic, and cost-effective synthesis avoided the use of harmful reducing agents. The synthesized silver nanoparticles were evaluated for their photocatalytic performance against organic dyes, catalytic reduction of p-nitrophenol, and cytotoxicity. The photocatalytic efficiency was tested against two organic pollutant dyes, Methylene Blue and Congo Red, under sunlight irradiation and in the presence of sodium borohydride. The 266.67 ppm silver nanoparticles achieved faster degradation of Methylene Blue under sunlight alone, whereas both 4000 ppm and 266.67 ppm silver nanoparticles showed enhanced Congo Red degradation under combined sunlight and sodium borohydride conditions. Degradation of para-nitrophenol was investigated in the presence of 266.7 ppm silver nanoparticles, with the Bark_AgNP exhibiting immediate degradation upon sodium borohydride addition. Cytotoxicity evaluation using Artemia salina revealed 100% viability at both 800 ppm and 200 ppm AgNP concentrations, indicating their biosafety and potential environmental compatibility. Overall, these results demonstrate that green-synthesized F. indica-based silver nanoparticles possess efficient photocatalytic and non-toxic characteristics, making them promising candidates for sustainable environmental remediation applications.