Chitosan-NiFe2O4 Nanocomposite Synthesis for Effective Removal of Pb(II) and Zn(II) from Aqueous Solution

Abstract

The purpose of present work is to synthesize and investigate the use of chitosan-based nanobiocomposites integrated with magnetic nanoparticles (NiFe2O4) for the adsorptive removal of Pb(II) and Zn(II) ions from aquatic media. The research is focused on addressing the urgent global problem of heavy metal pollution, especially in aquatic environments, with effective and sustainable solutions. Chitosan nanoparticles are prepared using an ionic gelation method, which are then used to synthesize a magnetic nanobiocomposite via ultrasonication and chemical co-precipitation with Ni and Fe precursors. The structural, morphological, and elemental properties of the resultant chitosan-NiFe2O4 nanobiocomposite (Fe/Ni@Chitosan NCs.) are characterized using XRD, FTIR, and Electron Microscopy (TEM and FE-SEM). The adsorption tests were conducted in a batch system, with varying contact times, pH levels, adsorbent dosages, and temperatures. The experimental adsorption of Pb(II) and Zn(II) ions showed a good fit with model of Langmuir. The nanocomposite's computed Langmuir maximum adsorption capacity (qmax) values were (91.0581, 90.7080) mg/g for Pb(II) at pH (4.0±0.01) and Zn(II) at pH (6.0±0.01), respectively, at a temperature of 45°C. The thermodynamic assessment involved the determination of change of Gibbs free energy (ΔG), change of enthalpy (ΔH), and entropy ΔS. The observation of a positive ΔH value implies that the interaction between Pb(II) or Zn(II) adsorbed by Fe/Ni@Chitosan NCs is endothermic. On the other hand, a negative ΔG value suggests that the adsorption of these two ions occurs spontaneously.