Methyl Orange Adsorption onto Magnetic Fe₃O₄/Carbon (AC, GO, PGO) Nanocomposites

In this study, carbonaceous nanomaterials (Activated Carbon (AC), Graphene Oxide (GO) and Porous Graphene Oxide (PGO)) were synthesized and attached to Fe₃O₄ magnetic powder for the effective removal of synthetic Methyl Orange (MO). AC and GO were successfully conjugated with Fe₃O₄ whilst PGO was not due to its surface functional groups. The morphology and chemical structure of the Fe₃O₄/Carbon nanocomposites were characterized by the N₂ adsorption, Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD), Scanning electron microscope (SEM), Transmission electron microscope (TEM) and Vibrating sample magnetometer (VSM). Batch adsorption experiments were performed and showed significant removal efficiency of 90% at the first ten minutes for Fe₃O₄/AC nanocomposite. Analysis of adsorption equilibrium revealed that AC/Fe₃O₄ is well fitted with Langmuir model, a homogeneous adsorption having an adsorption capacity of 270 mg/g. The GO/Fe₃O₄ can fit with both Langmuir and Freundlich models indicating multilayer adsorption on the surface of the adsorbent with an adsorption capacity of 81.9 mg/g. In the case of adsorption kinetics, both adsorbents follow the pseudo second order kinetics model showing high F?² values. Both adsorbents demonstrated advantageous superparamagnetic properties for their easy recovery from aqueous solutions and prospective applications to toxic removal in water and wastewater.