Adsorption properties of nickel oxide nanoparticles for removal of Congo Red from aqueous solution

The effective removal of dyes from aqueous wastewaters is among the most important issues for many industrialized countries. Removal of Congo Red (CR) dye from aqueous solutions was studied using nickel oxide nanoparticles. The operating variables studied were initial pH of solution, adsorbents dosage, temperature and contact time. The morphological information of nickel oxide nanoparticles were characterized using scanning electron microscopy (SEM) and X-ray diffractometer (XRD). The adsorbent exhibits high efficiency for CR adsorption and equilibrium can be achieved in 25 min. In order to investigate the efficiency of CR adsorption on nickel oxide nanoparticles, pseudo-first-order, pseudo-second-order kinetic models were studied. It was observed that the pseudo-second-order kinetic model fits better than other kinetic model with good correlation coefficient. Equilibrium data were fitted to the Langmuir model.