Abstract
Water contamination by toxic metals is an endless global environmental threat to human health, thus imperative to develop efficient multifunctional materials for water monitoring and remediation. Among the heavy metals, Pb(II) is among the most used and persistent pollutants that drastically affect the working ecosystem. Nonetheless, the evolution of inexpensive functional materials for the effective removal of heavy metals remains a prohibited challenge. In this work, the use of Nickel ferrite (NF) and Nickel ferrite/rGO (NG) nanocomposite for the adsorption of lead from an aqueous solution is examined. The physicochemical characterizations confirm the formation of magnetic nanoparticles with an average crystallite size of 35 and 30 nm and with a specific surface area of 59 and 110.9 m(2)/g for NF and NG. The magnetic measurements of NF and NG indicate multi-domain nanostructure with a saturation magnetization of 44.29 and 21.3 emu/g. Batch adsorption studies have been performed to determine the effect of pH, initial Pb(II) concentration, and the adsorbent dose on the removal performance of Pb(II) by NF and NG. The results prove that upon the addition of rGO to nickel ferrite nanoparticles, NG exhibits a maximum adsorption capacity of 390 mg/g under optimum conditions (pH = 6, T = 25 degrees C, [Pb(II)] = 20 mg/mL, [NG] = 15 mg). The adsorption kinetics of Pb(II) onto NF and NG obey the pseudo-second-order kinetic model with an R-2 value of 0.999 and 0.999, which is higher than the pseudo-first model and Elovich models. The adsorption isothermal findings indicate that the Langmuir model perfectly fits the experimental data than Freundlich, Temkin and Redlich-Peterson isotherm models, which illustrates the monolayer adsorption process for both NF and NG. The thermodynamic study elucidates that the adsorption of Pb(II) onto NF and NG is endothermic. NG nanocomposite can be easily recovered while maintaining a relatively high adsorption capacity of 85% after four continuous cycles. This study demonstrates the effectiveness of NG nanosorbent for removing lead residues that help in assessing other toxic heavy metals contaminants in wastewater.