Synthesis and characterization of deep eutectic solvent functionalized CNT/ZnCo2O4 nanostructure: Kinetics, isotherm and regenerative studies on Eosin Y adsorption

Serious concern has been raised over the use of organic compounds due to their adverse effects on the environment. Dyes which are part of these organic compounds have been reported to cause acute and chronic effect on both plants and animals. Therefore, this study aimed at investigating the mechanism of remediating dyes in an aqueous medium on deep eutectic solvent modified CNT/ZnCo2O4 hybrid nanostructure. A CNT/ZnCo2O4 hybrid nanostructure was synthesized. Deep eutectic solvent (DES) was also synthesized and used in the modification of CNT/ZnCo2O4. The DES modified CNT/ZnCo2O4 and unmodified CNT/ZnCo2O4 were characterized using Fourier-Transform Infrared Spectroscopy (FT-IR), X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). Thereafter, the modified and the unmodified were used for eosin Y dye adsorption. The investigation into the effects of adsorbate concentration, contact time and solution pH were done to determine experimental optimal conditions. Adsorption of eosin Y dye is favored at pH range 2-7. Sorption efficiency of DES modified CNT/ZnCo2O4 is far better than the unmodified CNT/ZnCo2O4. Adsorption data was better explained by the pseudo-second-order kinetics and Langmuir isotherm for eosin Y dye on both DES modified CNT/ZnCo2O4 and unmodified CNT/ZnCo2O4. Desorption experiment showed that DES modified CNT/ZnCo2O4 is reusable for at least five cycles. Therefore, DES modified CNT/ZnCo2O4 can be effectively used as potential adsorbents for the removal of organic dyes from wastewater.