Removal of acid blue 113 and reactive black 5 dye from aqueous solutions by activated red mud

Removal of acid blue 113 (AB113) and reactive black 5 (RB5) dyes from aqueous solutions by activated red mud was investigated at different reaction parameters. Activated red mud has higher removal efficiency for AB113 than that for RB5. This can be explained by a greater molecular size of RB5 than that of AB113 and by different binding affinity with the surface of the activated red mud. Equilibrium data was fitted well with Freundlich isotherm and the kinetic data followed a pseudo second-order model. Maximum adsorption capacity was 83.33 mg/g and 35.58 mg/g at pH 3 for AB113 and RB5, respectively.