Study on methylene blue adsorption of activated carbon made from Moringa oleifera leaf

Abstract

Activated carbon was prepared from Moringa oleifera leaf by NaOH activation (ACB), and was applied to remove methylene blus (MB) from aqueous solution. The ACB was characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), and Fourier Transform-Infrared Spectroscopy (FT-IR). The isoelectric point of ACB, pHzpc = 8. Investigation of some factors affecting the adsorption capacity of ACB by the method of static adsorption results: The time to reach adsorption equilibrium is 90 min. The best adsorption pH for MB is 7, the adsorbent dosage is 1.67 g/L. The adsorption on ACB obeys isothermal absorption models of Langmuir, Tempkin and Freundlich, single layer absorption under heterogeneous suface condition, existence weak interaction between absorbent and adsorbant, determine the maximum adsorption capacity for MB of qmax = 136.99 mg / g and constant KL = 0.07 (L / mg). The MB adsorption process of ACB materials is physical adsorption, self-evolution, exothermic and follow the model of second apparent adsorption kinetics.