Magnetic ZnFe2O4@chitosan encapsulated in graphene oxide for adsorptive removal of organic dye

Graphene-based multifunctional composites were prepared by encapsulating of magnetic ZnFe2O4@chitosan (ZnFe2O4@CS) particles into graphene oxide (GO) layers. The obtained ZnFe2O4@CS/GO were characterized using scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Adsorption of basic fuchsin (BF) onto the ZnFe2O4@CS/GO was investigated using pH, adsorption time, initial BF concentration and temperature. Kinetic data and adsorption isotherms were better fitted by a pseudo-second-order kinetic model and Langmuir isotherm model, respectively. The values of activation parameters such as free energy (ΔG, −14.02 to −16.56 kJ mol−1), enthalpy (ΔH, 23.27 kJ mol−1) and entropy (ΔS, 127.75 J mol−1 K−1) were calculated, suggesting that the adsorption was a spontaneous, favorable and endothermic process in nature. The results demonstrated that the ZnFe2O4@CS/GO composites are potentially suitable materials for the removal of organic dyes from large volumes of wastewater.