Application of a rotating packed bed contactor for removal of Direct Red 23 by adsorption

In this work, a rotating packed bed (RPB) contactor was applied to adsorb Direct Red 23 dye onto commercially available activated carbon. A RPB is a doughnut shaped contactor, which rotates on a vertical axis and centrifugal force acts as the driving force for fluid-particle contact in the contactor. This centrifugal force, which is several times higher than the gravitational force, aids the adsorption process with enhanced mass transfer coefficient. The commercially available activated carbon used in this work had moderate BET surface area of 583 m2 g−1 and was mainly meso-porous with an average pore size of 22 Å. The adsorption characteristics of the activated carbon were studied in a shake flask and a RPB. The dye removal in RPB was 93% compared to 55% in a shake flask in 5 h for the same amount of activated carbon and dye solution. Rotor speed and feed rate were important parameters for the removal of the dye in a RPB. It was found that rotor speed of 628 rpm and feed rate of 40 L h−1 yielded the best adsorption efficiency.