Adsorption studies for the removal of hexavalent chromium using fly ash of waste to energy power plant

Abstract

Chromium is the most common pollutant discharged in industrial effluent and reported to be present beyond permissible limits causing various health problems like carcinogenicity. Therefore, it must be removed from industrial effluent before its discharge. Several physico-chemical methods have been used for the removal of Cr (VI) from industrial effluents. Adsorption using activated carbon is quite efficient for the removal of Cr (VI) from industrial effluents. However, it is a costly process and the regeneration of activated carbon is difficult. Hence, in the present work, efforts have been made to explore the use of fly ash collected from the ‘Waste to Energy Power Plant’ as a low cost adsorbent. In order to maximize the Cr (VI) removal from simulated aqueous solutions, effects of various parameters (adsorbent dose, contact time, pH and initial metal ion concentration) on Cr (VI) adsorption were investigated by batch adsorption experiments. By optimizing the conditions for Cr (VI) adsorption using the fly ash, removal of hexavalent chromium from the aqueous solution (10 μg Cr/ml) was increased from 4% to approx. 99%. This shows that fly ash of agricultural waste burning can be used as an adsorbent for the removal of Cr (VI) at low concentration.