Chemical regeneration of activated carbon used for dye adsorption

Adsorption by activated carbon is widely used to remove organic pollutants from waters and wastewaters. However, the economical competitiveness of the activated adsorption process depends upon the reusability of exhausted carbon. This study investigated the chemical regeneration of activated carbon presaturated with two different dyestuffs by various organic solvents, redox agents, acids, and bases using batch and column experiments. From the batch desorption test results, 60% acetone in water and 40% isopropanol in water were found to be the optimal regenerants for the red and yellow dyes, respectively. A higher desorption temperature could improve the dye desorption efficiencies using acetone and isopropanol. The column test results showed that the carbon bed adsorption capacity decreased dramatically but seemed to be stabilized after 3 repeated adsorption/desorption cycles. (C) 2010 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.