The uptake of MB onto RPR and APR was increased with the increase in contact time. The adsorption equilibrium at 110 min was achieved for RPR and 90 min for APR. Compared to APR, RPR is more time consuming and also the percentage of dye removal is less. Initial adsorption was rapid due to the adsorption of dye onto exterior surface, after that dye molecules enter into pores (interior surface), a relatively slow process [20]. Data on the adsorption kinetics of dyes by various adsorbents have shown a wide range of adsorption rates. For example, the effect of contact time for the adsorption of Orange-G and Crystal Violet dye by bagasse fly ash was studied for a period of 24 h -1 for initial dye concentrations of 10 mg L at 30 °C [21]. Mall et al. [21] reported that after 4 h of contact, a steady-state approximation was assumed and a quasi-equilibrium situation was achieved.