Synthesis and Application of Magnetic Fe₃O₄@GO-3,5-Diaminopyrazole Nanocomposite for Pb(II) Adsorption: Optimization and Mechanism
نویسندگان
1 Department of Chemistry, Arak Branch, Islamic Azad University, Arak, Iran
2 Department of Chemistry, Mi.C., Islamic Azad University, Miyaneh, Iran
3 Department of Chemistry, Mi.C., Islamic Azad University, Miyaneh, Iran
4 Department of Fundamental Sciences, Marand Faculty of Technical and Engineering, University of Tabriz, Tabriz, Iran
5 Department of Chemistry, Mara.C., Islamic Azad University, Marand, Iran
doi
10.22052/JNS.2026.01.092چکیده
A novel magnetic nanocomposite, Fe₃O₄@GO functionalized with 3,5-diamino-1H-pyrazole (Fe₃O₄GO-PYR), was synthesized through modified Hummers’ and hydrothermal methods for efficient Pb(II) removal from aqueous solutions. Graphene oxide (GO) was prepared via oxidation of graphite, followed by deposition of Fe₃O₄ nanoparticles and anchoring of the pyrazole ligand under reflux conditions. Characterization by XRD confirmed crystalline Fe₃O₄ phases on GO sheets, FT-IR revealed functional groups (Fe-O at 566 cm⁻¹, C=O, N-H stretches), SEM showed uniform nanoparticle distribution with altered morphology post-functionalization, and EDX verified elemental composition (C, O, N, Fe). Central composite design (CCD) optimized parameters: pH (2.4-9.6), Pb(II) concentration (3-27 mg/L), adsorbent dose (3-27 mg), and contact time (1-49 min), achieving >95% efficiency at pH ~8-9, 15 mg dose, and 25 min. The point of zero charge (pHpzc ≈ 8) favored negative surface charge under basic conditions, enhancing electrostatic attraction with Pb²⁺. Langmuir isotherm and pseudo-second-order kinetics described monolayer adsorption, with favorable thermodynamics indicating spontaneity. This magnetically separable adsorbent addresses nanomaterial recovery challenges, offering scalable wastewater treatment for heavy metal pollution.
