Adsorption Studies on the Removal of Hexavalent Chromium-Contaminated Wastewater using Activated Carbon and Bentonite

In this study, the adsorption potential of activate d carbon and bentonite for removal of Cr(VI) ions f rom wastewater has been investigated. The study involves batch type ex periments to investigate the effects of initial con centration, adsorbent dose, agitation speed, contact time, temperature an d pH of solution on adsorption process and the eval uation of optimum conditions. The adsorption process has fit pseudo-second order kinetic models. Langmuir and Freundlich adsorption isotherm models were applied to analyze adsorption data, and both were found to be applicable to this adsorption process. Thermodynamic parameters, e.g., ∆G ◦ , ∆S ◦ and ∆H ◦ of the on-going adsorption process have also been calculated and found the sorption process as endothermic. Finally, it can be seen that bentonite was found to be more effective for the removal of Cr(VI) than activated carbon, under the same experi mental conditions.