Preparation and characterization of activated carbons from olive wastes by physical and chemical activation: Application to Indigo carmine adsorption

Present study explored the adsorptive characteristics of indigo carmine (ic) dye from aqueous solutions onto activated carbon (ac) prepared from olive solid waste (osw) impregnated with olive mill wastewater (omww) by chemical activation using potassium hydroxide (koh) and phosphoric acid (h3po4) as activation agents and physical activation using steam. the adsorbents were characterized by bet surface area,ftir spectra,scanning electron microscopy (sem),iodine number and methylene blue adsorption. influence of contact time,initial concentration (10-250 mg/l) and temperature (293-323 k) on adsorption capacity was investigated. the results shows that at all temperatures and for all initial concentrations the carbon activated by koh agent exhibit the best adsorption capacity followed by steam activated carbon and at last the carbon activated by h3po4. adsorption data were modeled using the pseudo-first-order,pseudo-second-order and intra-particle diffusion kinetic equations. it was shown that pseudo-second-order kinetic equation could best describe the adsorption kinetics. the equilibrium adsorption data of ic dye on activated carbon samples were analyzed by langmuir and freundlich models. the results indicate that the freundlich model provides the best correlation of the experimental data. adsorption of ic on activated carbon samples was favorably influenced by temperature. the positive values of the enthalpy change indicate that adsorption is endothermic. the results of this work indicate that activated carbon prepared from olive waste (ow) is suitable as adsorbent material for adsorption of ic dye from aqueous solutions. © 2017,university of mohammed premier oujda morocco.