Background : Dyes are one of the most hazardous material in industrial effluents which can cause several health problems in bio-life. The removal of dye from colored effluents has been attracted increasing attention in the recent decay. In this study raw, beneficiated and activated waste ash was evaluated as an adsorbent for removal of methylene blue (MB) from aqueous solution by batch adsorption method. Comprehensive characterization studies were carried out on each bio-adsorbents such as proximate analyses, bulk density, specific surface area, point of zero charge, pH and Fourier-Transform Infrared (FTIR) spectroscopy (which shows functional groups on adsorbents surface).
Results : The effects of pH, adsorbent dosage, initial dye concentration, and contact time were determined in order to know the optimum condition and adsorption potential of the adsorbents. The methylene blue (MB) removal efficiency of raw, beneficiated and activated bio-adsorbents from aqueous solutions was recorded to be 95.212%, 89.172%, and 84.504%, respectively. It is reported that adsorption efficiency of MB on each adsorbents was quite different due to electrostatic and dispersion interaction between the dye molecules and the surface property of the adsorbents. The obtained results were well fitted with Freundlich isotherm model and adsorption process follows the pseudo second order kinetics model for both adsorbents.
Conclusions : In fact the results showed that raw, beneficiated and activated waste ash bio-adsorbents could be employed as effective and economical alternative material in the near future use. Key words : Bio-adsorption, waste ash, adsorption capacity, surface modification, basic blue dye.