Green synthesis and characterization of iron oxide nanoparticles for efficient removal of ciprofloxacin from simulated and hospital wastewater

Abstract

This study explores the synthesis, characterization, and application of iron oxide nanoparticles (IONPs) derived from environmentally friendly sources, specifically mixture of orange peel and rice husk extracts, for the effective removal of ciprofloxacin from simulated and hospital wastewater. The synthesized IONPs were characterized using techniques such as U-Visible spectroscopy, Dynamic light Scattering (DLS), X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and Brunaur-Emmet-Teller (BET), which confirmed their optical properties, size/its distribution, crystalline structure, morphology, functional groups and surface area. The nanoparticles exhibited a uniform size distribution with Z-average of 94.4 nm and polydispersity index of 0.386, with peaks corresponding to several functional groups, Fe-O bond appearing at 693cm^-1 and a high surface area of 965.55 m²/g, enhancing their adsorption capacity. The efficiency of the IONPs in removing ciprofloxacin was evaluated through batch adsorption experiments with significant percentage reductions observed in both simulated and hospital wastewater. In hospital wastewater samples, the IONPs achieved removal efficiencies of up to 87.1%, indicating their practical applicability in real-world scenarios. Kinetic studies revealed that the adsorption process followed a pseudo-second-order model (R²= 0.9973), suggesting that the adsorption rate is influenced by the availability of active sites on the nanoparticles. Isotherm studies were conducted using Langmuir, Freundlich, and Temkin models, with the Freundlich model providing the best fit (R² = 0.99536), indicating heterogeneous adsorption on the nanoparticle surface. The findings highlight the potential of green-synthesized IONPs as an effective and sustainable solution for the removal of pharmaceutical contaminants from wastewater, contributing to environmental remediation efforts and public health protection.