Adsorption of Pb(II) ions from aqueous solutions by magnetite (Fe 3 O 4 ) nanoparticles functionalized with two different Schiff base ligands

In this study, Fe 3 O 4 magnetic nanoparticles were synthesized using a co-precipitation method and thereby modified with 3-aminopropyltriethoxy-silane (APTES) as the amine precursor, and 4- bromobenzaldehyde (BA) and 2-Formyl-1H-pyrrole (FP) as aldehyde precursors, to create Schiff ligands on the surface. In addition, FT-IR, FE-SEM, TGA-DTG, TEM, and XRD analyses were employed to characterize the nanoparticles. The resultant modified nanoparticles (Fe 3 O 4 -BA and Fe 3 O 4 -FP) were then applied for Pb(II) removal from aqueous solutions. The kinetic behavior of Pb(II) removal was studied through pseudo-firstorder and pseudo-second-order adsorption experiments, resulting in the rate constants. According to the findings, the metal adsorption process followed a pseudo-second-order kinetic reaction. Assessing the equilibrium behavior of the adsorption process through Langmuir and Freundlich models revealed that the adsorption equilibrium data for Pb(II) ions on Fe 3 O 4 -BA and Fe 3 O 4 -FP followed the Langmuir and Freundlich isotherm models, respectively. Moreover, the results showed that the adsorption process of metal ions by the Fe 3 O 4 -BA and Fe 3 O-FP nanoparticles was affected by operating parameters such as pH, temperature, metal ion concentration and mass of adsorbent.