Synthesis and characterization of cupric oxide (CuO) nanoparticles and their application for the removal of dyes

Abstract

In the present work, cupric oxide (CuO) nanoparticles (NPs) were prepared by adopting aqueous precipitation method using copper sulphate 5-hydrate as a precursor and NaOH as a stabilizing agent. This gives a large scale production of CuO-NPs which are utilized for the removal of methylene blue (MB) dye. The CuO NPs were characterized for the studying of their structure and composition from XRD which reveals the single phase monoclinic structure. The surface morphology of these NPs was carried out by using scanning electron microscopy (SEM). Moreover, the effect of optimization parameters such as time, concentration and temperature was also examined. Spectrophotometric technique was used to evaluate the removal of MB in aqueous solution by NPs. The equilibrium adsorption of cationic dye (MB) was carried out at various temperatures ranging from 303 to 318 K ± 2K. The adsorption isotherm equations like Langmuir, Freundlich and Dubinin-Radushkevich were applied and the values of their respective constants were evaluated by adopting graphical method. Thermodynamic and kinetic studies were also performed to determine the feasibility of the process. The maximum MB removal was observed to be 88.93%. The pH of point zero charge (pH_PZC) of adsorbent was also estimated by pH drift method. The results indicate that aqueous precipitation method is a reliable and cheap method for the development of CuO-NPs which can be effectively used for the removal of dyes from effluents. This method is beneficial for the remediation of industrial waste.

Key words: CuO nanoparticles, XRD, SEM, methylene blue, adsorption, UV Spectrophotometer.