Synthesis and Characterization of Magnetic CoFe1.9Cr0.1O4 Nanoparticles by Sol-gel Method and Their Applications as an Adsorbent for Water Treatment

Water contamination by synthetic dyes is considered as a serious environmental issue, globally. In this study, the adsorptive removal of a very toxic cationic dye, methylene blue (MB), from aqueous solution was investigated using spinel ferrite, CoFe1.9Cr0.1O4 (CFC), magnetic nanoparticles as an adsorbent. CoFe 1.9Cr0.1O4 powder was successfully synthesized via a sol-gel process and characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) techniques. The effect of various experimental parameters on MB rem oval including; contact time, initial dye concentration, adsorbent dosage, solution pH and temperature were investigated. The results revealed that about 94 % of MB was removed under the optimal operational conditions. The adsorption kinetics showed that adsorption data were better described by pseudo-second-order model (PSO). In addition, the adsorption isotherms follow Langmuir isotherm model and the maximum monolayer adsorption capacity was found to be 11.41 mg/g. The calculated thermodynamic parameters (i.e., ∆G o , ∆H o , ∆S o ) indicate that the proposed adsorption process of methylene blue onto CoFe1.9Cr0.1O4 nanoparticles is exothermic and spontaneous in nature. The results suggest that the synthesized magnetic nanoparticles (CFC) can be employed for the removal of toxic cationic synthetic dyes from wastewater.