Green Synthesis of Iron Oxide Nanoparticles (α-Fe2O3 NPs): Investigating the Efficiency of Photocatalytic Degradation and Antimicrobial Activity

Abstract

The present study reports the green synthesis of iron oxide nanoparticles (α-Fe2O3 NPs) using Azadirachta indica leaf extract as a sustainable stabilizing agent and evaluates their antimicrobial and photocatalytic potential. The synthesized nanoparticles were characterized by UV–Visible, FT-IR, XRD, FESEM-EDS and TEM techniques. UV–Visible analysis confirmed nanoparticle formation, while XRD revealed the rhombohedral crystalline phase of α-Fe2O3 with high crystallinity. FT-IR analysis indicated the involvement of phytochemicals from A. indica in nanoparticle synthesis and stabilization. FESEM and TEM images showed predominantly irregular agglomerated rod-shaped nanoparticles. EDS analysis confirmed the elemental composition of iron and oxygen. Photocatalytic performance was evaluated through the degradation of Rhodamine B dye under xenon arc lamp irradiation simulating sunlight. The synthesized α-Fe2O3 NPs achieved a maximum degradation efficiency of 95.38% at 180 min and followed pseudo-first-order kinetics. The effects of pH, catalyst reusability, and stability confirmed the excellent photocatalytic performance and durability of the nanoparticles. The antimicrobial activity of α-Fe2O3 NPs was assessed against selected bacterial pathogens (E. coli, P. aeruginosa, B. subtilis, and S. aureus) and fungal strains (C. albicans, A. flavus, and A. niger) using the disk diffusion method. The nanoparticles exhibited broad-spectrum antimicrobial activity, with the highest inhibition observed against E. coli. These findings demonstrate that A. indica-mediated α-Fe2O3 NPs are effective multifunctional nanomaterials with significant potential for wastewater treatment, environmental remediation, and antimicrobial applications.