Study affecting factors on the recovery of some heavy metal ions from aqueous solutions using natural clay

Abstract

This study includes the ability of selected clays, which are (Iraqi bentonite, Iraqi Kaolin and Italian Kaolin) for the adsorption of heavy metals (Cu+2, Zn+2, Cd+2 and Pb+2) from aqueous solution. As preliminary experiment, the extraction operation of these ions were carried out by using batch method at (pH= 6.7 and 30 ̊C) for 10 min as a contact time to indicate the best type of these clays for removing these ions. Different temperatures (30 ̊C, 40 ̊C, 50 ̊C) and times (10 min, 20 min, 30 min) were also carried out at various pH (4 , 6.7 and 9) to select the optimum conditions for removing these ions. Flame atomic absorption spectrophotometer was used to determine the concentration of these ions. The obtained results showed that the ability of the studied clays to removal these ions at (pH=6.7, 30 ̊C and 10 min contact time) were as follows: Iraqi bentonite> Iraqi Kaolin>Italian Kaolin The results were also showed that the percent adsorption for removal the most ions at (pH = 9, 30 ̊C and 10 min contact time) was 100%. The increase of reaction temperature and contact time led to increase the adsorption percent. The adsorption percent for all these ions was half or less than half when the solution of these ions containing foreign ions.