Eco- Friendly Synthesized Ni (NO₃)₂ Nanoparticles Using <em>Tridax Procumbens</em> L. As Potent Antimicrobial And Photo Catalytic Degradation of AZO Dye

Green synthesis of metal-based nanomaterials has emerged as an eco-friendly alternative to conventional chemical routes due to its sustainability, cost-effectiveness, and reduced environmental impact. In the present study, nickel nitrate nanoparticles (Ni(NO₃)₂ NPs) were biosynthesized using Tridax procumbens leaf extract as a reducing and stabilizing agent. The formation of Ni(NO₃)₂ nanoparticles was confirmed through UV–Visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray analysis (EDAX). XRD analysis revealed the crystalline nature of the synthesized nanoparticles with a face-centered cubic structure, while SEM images showed agglomerated, quasi-spherical particles with rough and porous surfaces. FTIR analysis confirmed the involvement of plant-derived phytochemicals in nanoparticle stabilization. The biosynthesized Ni(NO₃)₂ nanoparticles exhibited significant antimicrobial activity against selected bacterial and fungal strains in a concentration-dependent manner. Furthermore, the photocatalytic performance of the nanoparticles was evaluated for the degradation of Yellow RGB Red Azo dye under visible light irradiation. The degradation efficiency was strongly influenced by pH and catalyst dosage, with maximum degradation (~98%) achieved at alkaline pH (10) and higher catalyst loading. Kinetic studies demonstrated that the dye degradation followed pseudo-first-order kinetics. Scavenger experiments revealed that hydroxyl and superoxide radicals played a dominant role in the photocatalytic degradation mechanism. The results highlight the potential of Tridax procumbens-mediated Ni(NO₃)₂ nanoparticles as efficient, sustainable materials for antimicrobial applications and wastewater treatment.