Vol. 1, Issue 13, Part L (2015)

Abstract
The present work examined the influence of textural and some physico-chemical properties of two clays smectite and kaolin in the removing of lead (II) ions in aqueous solutions. The influence of some environmental parameters such as pH, contact time and initial concentration were examined. Residual lead concentration reaches equilibrium in 30 minutes for Smectite and 40 minutes for kaolin. The pseudo-second order and Elovich kinetics models best described adsorption kinetics on kaolin whereas the pseudo-first order or Laguerre kinetic model followed the lead (II) sorption on Smectite. For the two clays intraparticle diffusion seems to be the rate limiting-step. Batch sorption studies showed that Langmuir model gives a better fit for the two clays compared to the Freundlich adsorption isotherm. Adsorption mechanism is due essentially to the electrochemical ion-exchange between lead (II) and clays surfaces and the complexation reaction. Mineralogical composition of each clay strongly influences the sorption process.