Adsorption kinetics and column operations for the removal and recovery of malachite green from wastewater using bottom ash

The thermal power plant waste material, 'bottom ash' was utilized as a potential adsorbent for the toxic textile dye 'malachite green'. Preliminary information was gathered by batch adsorption studies, which include effect of pH, adsorbent dose, contact time, adsorbate concentration and temperature. Plausible mechanism of the on-going adsorption process and thermodynamic parameters involved were obtained by carrying Out kinetic measurements. The data obtained was successfully used to equate Langmuir and Freundlich adsorption isotherm models. A fixed-bed column was designed and necessary parameters were calculated by applying mass transfer kinetic approach. Attempts were also made to recover dye and regenerate the column. (C) 2004 Elsevier B.V All rights reserved.