Abstract

This article attempts to synthesize iron oxide nanoparticles (IONPs) using an eco-friendly method involving an aqueous extract of Ziziphus lotus leaf as a reducing, nucleating, and capping agent. This green synthesis presents a healthier alternative to conventional physicochemical approaches. The effects of precursor and leaf extract concentration, reaction time, and temperature on IONPs yield were analyzed using hybrid approach optimization based on Box-Behnken Design (BBD) and Genetic Algorithm-Artificial Neural Network (GA-ANN). The results indicated that reaction time and extract concentration significantly influence the dry weight of IONPs. Optimal conditions for biosynthesis, determined by GA-ANN, were found to be 1 h, 62 °C, 0.099 M precursor concentration, and 100 g/L extract concentration. Morphological, optical, structural, and catalytic properties of the IONPs were investigated using X-ray diffraction (XRD), UV–visible spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM-EDX). The biosynthesized IONPs, comprising a mix of magnetite (Fe3O4) and ?-hematite (Fe2O3) were spherical with particle sizes ranging from 34 to 54 nm. These IONPs exhibited antimicrobial activity against gram-negative bacteria (P. aeruginosa and E. coli) and fungi (C. albicans and F. oxysporum), The biosynthesized IONPs demonstrated significant catalytic activity in degrading methylene blue, especially when combined with hydroxylamine (HA), enhancing degradation efficiency from 20.38 % to 91.79 % with H2O2 and from 98.38 % to 99.11 % with NaClO within 30 min. © 2025 Elsevier B.V.