Chromium Ions Removal from Wastewater Using Activated Iraqi Bentonite

Abstract

In this work, a low cost and abundant modified Iraqi bentonite was used for the removal of heavy metal Cr +3 ions from wastewater by adsorption onto raw and activated bentonites.The modification of raw bentonite was carried out by thermal activation (TAB), acid activation (AAB) and combined acid and thermal activation (AAB/TAB).The adsorption process was characterized by FTIR and BET.The results showed that the combined acid and thermal activated bentonite (AAB/TAB) has the optimum measured surface area 109.85 m²/g compared to that of all other types of activated bentonite.The optimum conditions for batch adsorption of Cr 3+ ions and the maximum adsorption efficiency were found to be 99.83% for raw bentonite at 100 mg; 99.84 % for (TAB) at 75 mg ; 99.80% for (AAB) at 50 mg and 99.83% for (AAB/TAB) at 25mg.The maximum adsorption efficiency occurred at pH 6.The equilibrium data described by the Langmuir and Freundlich isotherm equations showed that the Langmuir isotherm gives better fit to the experimental data than Freundlich adsorption isotherm.