Adsorption and Leaching Behavior of Copper, Zinc and Lead Ions by Three Different River Nile Sediments at Aswan, Egypt

The present study was carried out to investigate the adsorption and leaching behavior of cu2+, zn^2+ and pb^2+ by sediments collected from the western banks of three different sectors along river nile at aswan governorate, egypt. the feasibility of sediments for the removal of cu^2+, zn^2+ and pb^2+ from aqueous solutions was tested under the effect of three conditions (ph, initial metal concentration and contact time). by increasing ph, the adsorption of cu^2+ and pb^2+ by sediments decreased while that of zn^2+ increased. the optimum ph values for cu^2+, zn^2+ and pb^2+ removal were determined as 5, 8.5 and 5, respectively. the adsorption capacities of sediments for metal ions were in the order of pb^2+ > cu^2+ > zn^2+. the maximum uptake for cu^2+, zn^2+ and pb^2+ by sediments occurred at contact times of 48 h, 24 h and 72 h, respectively. adsorption data were fitted well by freundlich, dubinin–radushkevich and temkin isotherms. the experimental results obtained were analyzed using two adsorption kinetic models, pseudo-first-order and pseudo-second-order, in which pseudo-second-order equation described the data more than pseudo-first-order one. the average leaching percentages of cu^2+, zn^2+ and pb^2+ from sediments were 0.77%, 2.72% and 0.38%, respectively, with respect to ph, 0.83%, 2.49% and 0.38%, respectively , with respect to temperature, and also 0.79%, 2.34% and 0.38%, respectively with respect to contact time. the leaching percentages of metal ions from sediments were in the order of zn^2+ > cu^2+ > pb^2+.