Modification of magnetic active carbon nanocomposite with SiO2 and Zincon for efficient removal of Pb(II) and 201Pb(II); multivariate optimization and adsorption characterization

Abstract

This research focuses on the development of a novel surface-modified green magnetic carbon-based nanocomposite as a new adsorbent for the efficient removal of Pb(II) and 201Pb(II) from water sources. The nanocomposite was synthesized using pomegranate peel extract modification, some renewable and sustainable raw material rich in polyphenols and biologically active constituents. Then it was modified by SiO2 and Zincon for enhancement of its selectivity and performance. The prepared nanocomposite was characterized using various analytical techniques, including Fourier-transform infrared spectrophotometry (FTIR), field emission scanning electron microscopy (FESEM) coupled with energy-dispersive spectroscopy (EDS), vibrating sample magnetometer (VSM), Brunauer-Emmett-Teller (BET), and X-ray diffraction (XRD) analyses. To optimize the adsorption process, a multivariate optimization methodology based on the Box-Behnken design was employed. The optimal conditions were found to be: pH 5.4, adsorbent mass 4.0 mg, initial concentration of lead ion 54.0 mg.L-1. Adsorption isotherms and kinetic modeling studies were conducted to understand the adsorption behavior of the nanocomposite. The maximum capacity uptake was 513.5 mg.g−1. The results indicated that the surface-modified green magnetic carbon-based nanocomposite exhibited a high adsorption capacity and rapid adsorption kinetics for both Pb(II) and 201Pb(II). The pseudo-second-order kinetic model provided the best fit to the experimental data, suggesting chemisorption as the predominant adsorption mechanism. Thermodynamic analysis revealed that the adsorption process was spontaneous and exothermic, indicating the favorable nature of the adsorption.