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

Nano-ZnO was employed for the adsorption of 4C2NP from aqueous solutions in batch equilibriumexperiments to investigate its adsorption properties. The quantity of 4C2NP adsorbed onto nano- ZnOsurface was measured by UV-Vis spectrophotometer. The effects of contact time, adsorbent dose, pH, andinitial concentration of 4C2NP were investigated. The adsorption found to be strongly influenced by all theabove 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 andmaximum 4C2NP removal (46.5 %) was observed at pH =6. Also, removal efficiency of 4C2NP decreasedby increasing the initial concentration. Experimental data were analyzed by Langmuir and Freundlichisotherms. Experimental results indicated that the equilibrium adsorption data fitted well in the Freundlichisotherm equation with a correlation coefficient equal to 0.995.