Green synthesis of iron oxide nanoparticles (Fe2O3-NPs) from Citrus Limetta agrowaste for biological and photocatalytic applications.

Fruit waste is an abundant and eco-friendly green resource for the synthesis of nanoparticles, offering a sustainable alternative to conventional physical and chemical methods. In this study, we prepared green iron oxide nanoparticles (Fe2O3-NPs) with excellent biological and catalytic properties. The materials are synthesized from polyphenol-rich extracts of Citrus limetta (sweet lemon) peels. After extensive characterization via UV, XRD, FTIR, SEM, TEM, EDX, and PL, the materials were tested for their biological properties and catalytic degradation of 2-NP and Methylene Orange (MO). We observed excellent antibacterial properties of Fe2O3-NPs, especially against gram-negative bacteria, with MICs of 0.625 mg/mL against E. coli and 1.125 mg/mL against P. aeruginosa. The eco-friendly materials also resulted in potential antiparasitic potential against L. tropica, the parasite that causes leishmaniasis. Furthermore, the NPs exhibit remarkable antioxidant properties and considerable enzyme inhibition ability against α-amylase, α-glucosidase, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE), indicating their potential usefulness in treating diabetes mellitus and Alzheimer's disease. In addition to their outstanding biological properties, NPs have shown remarkable catalytic properties in the degradation of environmental pollutants such as 2-NP and methyl orange (MO). 98.32% degradation was observed for 2-NP in just 15 min, whereas 97.5% degradation was recorded for MO in 25 min. This excellent catalytic potential shows that the multifunctional materials synthesized from waste biomass can be utilized for important biological and environmental applications.