Synthesis of Graphene-Wrapped Iron as an Efficient and Recyclable Magnetic Adsorbent for Removal of Fuchsin from Aqueous Solution

The graphene-wrapped iron (GFe) was synthesized by annealing the sucrose-ferric chloride solution. The GFe was utilized as a magnetic efficient adsorbent to adsorb fuchsin from aqueous solution. Due to the presence of iron inside the GFe, the fuchsin-adsorbed GFe was separated easily from the aqueous solution using a permanent magnet. For the adsorbent characterization, the structure of graphene was investigated by X-ray diffraction and X-ray photoelectron spectroscopy. The grain size of graphene was acquired by field emission scanning electron microscope and Raman spectroscopy. The weight % of iron inside the graphene was estimated using energy-dispersive X-ray spectroscope. Adsorption kinetic, adsorption isothermals, influence of pH, and regeneration of the GFe were also investigated. The adsorption kinetic data was analyzed using pseudo-second-order, Elovich, and intraparticle diffusion models. In addition, the Langmuir, Freundlich, and D-R models were utilized to analyze the adsorption isothermal data. The results revealed that the adsorption process of fuchsin onto the surface of the GFe was due to the combination of chemisorption and physisorption. The maximum adsorption capacity of fuchsin by GFe was 12.71 mg/g. Besides, the adsorption capacity of fuchsin by the GFe was stable at the pH range of 3.56 to 9.47. The GFe could be regenerated by immersing in ethanol. The removal ratio decreased from 96% to 90% after 5 regeneration cycles.