REMOVAL OF HEAVY METAL IONS FROM AQUEOUS SOLUTION BY APPLICATION OF LOW COST MATERIALS

Biosorption capability of low cost materials for cadmium and chromium ions removal has been investigated as a function of appropriate equilibrium time, concentration of adsorbate and pH using batch system. Kinetic data and equilibrium isotherms were obtained. Equilibration time for maximum biosorption of Cadmium was 60 minutes, optimum pH was 6 and initial concentration 2mg/L for both Ulmus leaves and Platanus orientalis leaves respectively. Simultaneous adsorption of cadmium and chromium ions was studied using a medium that contained 2mg/L of each metal ion. Results indicated that Langmuir model gave a better fit to the experimental data in comparison with the Freundlich equation. Sorption kinetics was well described by an empirical power function within the reaction times. All sorbents exhibited greater sorption capacity for Cd (II) than Cr (VI) and the presence of both metal ions reduced the tendency for either to be sorbed although Cd (II) sorption was affected to a greater extent than that of Cr (VI). The Langmuir binding strength parameter (k) was always greater for Cd (II) than Cr (VI). However, these k values tended to increase as a result of the simultaneous presence of both metal ions that may indicate competition for sorption sites promoting the retention of both metal ions on more specific sorption sites.