Box–Behnken design for the optimization of methylene blue and methyl orange removal from aqueous solution by activated carbon

Abstract

In this work, experimental design approach was adopted for the optimization of the removal of anionic and cationic model dyes (methylene blue and methyl orange) by activated carbon. A Box–Behnken surface statistical design with three factors and three-level combined with response surface modelling was employed to maximize dyes removal from aqueous solution. Three factors were used; solution pH, dyes concentration and activated carbon ratio to aqueous volume. Experimental results showed that solution pH has a positive effect on the adsorption of MB and a negative effect on the adsorption of MO. MO adsorption was more influenced by dye concentration in solution compared to MB adsorption. On the other side, MB adsorption was more influenced by the mass ratio of activated carbon compared to MO adsorption. The mass ration of activated carbon influence more MB adsorption at low dye concentration. In addition, at low solution pH, MO adsorption depends strongly on its concentration in solution