Orange Peel-Mediated Synthesis of Fe3O4 Nanoparticles for the Removal of Ibuprofen from Domestic Wastewater

Abstract

This study explores the eco-friendly production of iron oxide nanoparticles utilizing oranges orange peel extract, focusing on their characterization and application in removing ibuprofen from domestic wastewater. The study investigated the adsorption of ibuprofen onto the nanoparticles under various conditions, encompassing pH levels, starting adsorbate concentration, duration of contact, amount of adsorbent, and temperature. In-depth analysis of the adsorption data using diverse isotherm and kinetic models provided valuable insights into the mechanisms and parameters involved. Characterization revealed that the nanoparticles display a nanocrystalline structure with a cubic shape, high surface area, and are primarily composed of iron (Fe) and oxygen (O). They possess a Z-average of 42.60, feature a Fe-O bond at 693.30 cm^-1, and show UV-Visible absorbance at 285 nm. Batch adsorption experiments demonstrated that the removal efficiency improved with increased adsorbent doses (20-100 mg), reaching a peak efficiency of 80.15% at 100 mg. However, the adsorptive capacity diminished as the temperature rose above room temperature, and the initial adsorbate concentration showed an inconsistent pattern with the optimum adsorption at 10 mg/L and contact time of 15 min and a pH of 7. The adsorption process conformed to a pseudo-second-order model. (R²=0.92174), indicating a reliance on active sites and ibuprofen concentration, suggesting chemisorption mechanisms. The Langmuir isotherm model best aligned with the data (R²=0.93461), indicating monolayer coverage on nanoparticles with a strong affinity for ibuprofen. Thermodynamic analysis verified that the adsorption occurred spontaneously (negative ΔG) and exothermic (negative ΔH), consistent with decreased capacity at elevated temperatures. This study demonstrates the efficiency of iron oxide nanoparticles (IONPs) in reducing ibuprofen levels in domestic wastewater, with consistent reduction percentages ((1.30-0.0544 mg/L) highlighting the method's reliability and scalability for treating pharmaceutical contaminants across various environmental settings.