Remediation of Lead-Contaminated Water Using Green Synthesized Iron-Oxide Nanoparticles: Performance and Mechanism

Lead (Pb(II)) ions in water pose a significant threat to both human health and aquatic ecosystems. Various approaches have been employed for wastewater treatment, but adsorption is often preferred due to its effectiveness. However, its practical application is limited by the large quantities of adsorbent required, which consequently increases operational costs. In this study, orange-modified iron-oxide nanoparticles (O-Fe3O4) are synthesized from agro-waste mass (orange peel), and adsorption experiments were conducted for the removal of Pb(II) from aqueous solution. Characterization studies confirm that O-Fe3O4 nanoparticles possess a mesoporous hexagonal nanocrystalline structure, with diameters measuring less than 100 nm. The adsorption process was optimized using a central composite design framework combined with response surface methodology. The analysis of interaction effects demonstrated that they significantly influenced the effectiveness of adsorption removal. The study revealed that an initial concentration of 25 mg/L, a dosage of 0.2 g/L, a contact period of 90 min, and a pH of 5.5 were the optimum conditions to achieve above 95% of Pb(II) removal. The green synthesized O-Fe3O4 nanoparticles, which presented high efficacy, makes it a promising option for implementing the sustainable water purification.