Hanif Ardhiansyah, Tutuk Djoko Kusworo, Andri Cahyo Kumoro
The development of magnetically recoverable nanocomposites with high structural stability and surface functionality is crucial for catalytic and biocatalytic processes in aqueous environments. In this work, a Fe₃O₄/GO–PEG nanocomposite was synthesized via a co-precipitation route followed by PEG functionalization to improve dispersibility, chemical robustness, and reusability. Comprehensive characterization using XRD, FTIR, TEM, BET, VSM, DLS, TGA, and ICP–OES confirmed the formation of monodisperse Fe₃O₄ nanoparticles (7-15 nm) uniformly anchored on GO sheets. XRD and FTIR analyses verified the Fe–O–C coordination and amide (–CO–NH–) linkages, indicating successful PEG grafting. The nanocomposite exhibited a mesoporous structure (6-9 nm) with a high surface area (137.4 m²·g⁻¹) and retained superparamagnetic behavior (Mₛ = 55.8 emu·g⁻¹), enabling rapid magnetic separation. DLS and zeta potential measurements demonstrated that PEG-induced steric stabilization effectively suppressed aggregation and reduced Fe leaching by 53% under ultrasonic conditions. The synergistic effect of GO support and PEG coating provides enhanced colloidal stability, chemical durability, and magnetic recyclability, making the material a promising platform for ultrasonic-assisted delignification and enzyme immobilization. This study establishes a clear structure–stability–function correlation in Fe₃O₄/GO–PEG systems, elucidating the critical role of PEGylation in preserving magnetism while mitigating degradation during sonochemical and biocatalytic operations. © 2026, Walailak University. All rights reserved.
Department of Chemical Engineering, Faculty of Engineering, Diponegoro University, Semarang, 50239, Indonesia; Department of Chemical Engineering, Faculty of Engineering, Universitas Negeri Semarang, Semarang, 50299, Indonesia
