Effect of Cations and Anions Presence on Cadmium Sorption Kinetics from Aqueous Solutions by Dried Sunflower Leaves

The effect of ions presence such as: Na + , K + , Ca 2+ , Cl , SO4 2and CO3 2, at various initial concentrations, on the kinetics of cadmium sorption by dried sunflower leaves was studied at 25°C in batch conditions. The presence of these ions in solution was found to inhibit the uptake of cadmium by dried sunflower leaves at different degrees. Na + and K + ions have no significant effect. For Ca 2+ , SO4 2and CO3 2ions, the effects ranged from an inhibition of cadmium by Ca 2+ and CO3 2to a weak inhibition by SO4 2. Cl -1 ion was found to enhance slightly cadmium uptake level. Simplified kinetics model: a pseudo second-order equation adequately described the kinetics of cadmium sorption by sunflower leaves: alone and in the presence of cations or anions. In the presence of cations, cadmium sorption kinetics by dried sunflower leaves was largely determined by external mass transfer diffusion steps. In the presence of anions, cadmium sorption kinetics was largely determined by intraparticle transfer diffusion steps.