REMOVAL OF COPPER IONS FROM WASTE WATER BY ADSORPTION WITH MODIFIED AND UNMODIFIED SUNFLOWER STALKS

Abstract

Unmodified and modified sunflower stalks were examined for adsorption as a replacement of expensive activated carbon which has been recognized as a highly effective adsorbent for the removal of heavy metal-ion.Two modes of operation were used, batch mode and fixed bed mode. In batch experiment the effect of sunflower stalk doses (2,3,4,5 and 6g/L) with constant initial copper concentration of 100 mg/L and constant particle size less than1.18 mm was studied.Batch kinetics experiments showed that the adsorption rate of copper ion by sunflower stalks was rapid and reached equilibrium within 60 min. Adsorption models Freundlich, Langmuir and Freundlich-Langmuir were fitted to experimental data and the goodness of their fit for adsorption was compared. In the fixed bed isothermal adsorption column, the effect of particle size (1.18-2.36, 2.36-4.75 and 4.75-9.00) mm, influent flow rate (2,4and 6) L/hr, bed depth (25, 30 and 35) cm and initial metal concentration (100 and 150) mg/L was studied. In addition, the modification of sunflower stalks could enhance their natural capacity. Sunflower stalks were modified by activation with nitric acid. The results of this study show that sunflower stalk, both modified and unmodified, is an efficient adsorbent for the removal of copper from waste water. Percent removal of copper reaches 100% when particle size (2.36-4.75)mm ,bed depth 35 cm and influent flow rate 4 L/hr.