Adsorption of 4-Chloro-2-nitrophenol onto Nano-ZnO

Nano-ZnO was employed for the adsorption of 4C2NP from aqueous solutions in batch equilibrium experiments to investigate its adsorption properties. The quantity of 4C2NP adsorbed onto nano- ZnO surface was measured by UV-Vis spectrophotometer. The effects of contact time, adsorbent dose, pH, and initial concentration of 4C2NP were investigated. The adsorption found to be strongly influenced by all the above parameters. The optimized conditions for maximum amount of adsorption were also determined. The results showed that adsorption of 4C2NP by nano-ZnO reached to equilibrium after 60 minutes and maximum 4C2NP removal (46.5 %) was observed at pH =6. Also, removal efficiency of 4C2NP decreased by increasing the initial concentration. Experimental data were analyzed by Langmuir and Freundlich isotherms. Experimental results indicated that the equilibrium adsorption data fitted well in the Freundlich isotherm equation with a correlation coefficient equal to 0.995.