Valorization of Vigna Unguiculata (Cowpea) Husk for Green Synthesis of Silver Nanoparticles and Evaluation of Its Free Radical Scavenging Potentials Towards Indoor Enironmental Application

The escalating challenge representing free radicals like Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS) necessitates innovative solutions within the confines of green nanotechnology. This research focuses on the free radical scavenging activities and the green synthesis of silver nanoparticles (AgNPs) from Vigna unguiculata (cowpea) husk aqueous extract for valuable possible indoor environmental uses. For the green synthesis of the silver nanoparticles, photo-activation was used, as Vigna unguiculata husk extract was employed as both a reducing and capping agent along with silver nitrate as the precursor. AgNPs synthesis, and subsequent characterizations were carried out utilizing UV-Vis spectra, Fourier Transform Infrared (FTIR) spectra, Energy Dispersive X-Ray (EDX) and Transmission Electronics Microscopy (TEM). The UV-Vis spectra exhibited a maximum absorbance of 448.0 nm, demonstrating the presence of the silver nanoparticles, and the surface plasmon resonance both FTIR and EDX demonstrated the presence of Ag. FTIR shows the functional groups at 3430.171017.61 cm⁻¹, and silver at nm, which was attributed to the silver nanoparticles surface with the reducing and capping agents being phenolic compounds and proteins. TEM demonstrated silver spherical nanoparticles and EDX demonstrated the silver. 3 nm. The synthesized AgNPs scavenged free radicals quite efficiently, with activity percentages of 56.49 ± 0.2, 52.55 ± 0.2, and 48.09 ± 0.3 at 50, 100, and 150 µg/ml respectively. The assessed total phenolic content for these volumes were 59.46 ± 0.2, 50.15 ± 0.2, and 43.18 ± 0.3 µg/ml respectively for 50, 100, and 150 µg/ml. The biocompatible properties of the plant waste-mediated nanoparticles, combined with their free radical scavenging activities, present a promising green approach for mitigating oxidative stress in indoor environments. These research findings suggest potential applications in building materials, air filtration systems, and surface coatings to create oxidant-free indoor spaces while supporting sustainable development goals. This research contributes to the growing field of green nanotechnology through the biosynthesis of plant waste-mediated silver nanoparticles for free radical scavenging applications.