Process optimization and modeling of lead removal using iron oxide nanocomposites generated from bio-waste mass

Pb(II) ions in water bodies is a wide concern to the human beings as wells as aquatic organisms. Among various water-treatment techniques, adsorption is generally preferred, but it applications are limited due to the large amount of adsorbent needed and thus the increased operating cost. In this study, iron nanocomposites (T-Fe₃O₄) are synthesized from bio-waste mass (tangerine peel) and adsorption experiments are carried out for Pb(II) removal from aqueous solution. The characterization studies confirm the mesoporous hexagonal nano-crystalline structure of T-Fe₃O₄ nanocomposite having less than 100 nm diameter. The adsorption process was optimized using response surface methodology with a central composite design framework. The study of the interaction effects showed that they have significant effect on adsorption removal efficacy. The curvature nature of the contour plots confirmed the interaction intensity among the independent process variables. Based on the analysis, the optimum conditions to achieve 95% of Pb(II) removal were found to be for an initial concentration of 32.5 g/L, the dosage of 0.625 mg/L, the contact time of 95 min and pH of 4.5. Therefore, results confirm that the green synthesized T-Fe₃O₄ nanocomposite, which showed good efficiency, can be a potential candidate to achieve sustainable water purification.