Azure A Removal from Aqueous System Using Natural and Modified (Grape Stalk and Pomegranate Peel) Adsorbents

Abstract

Grape stalk (GS) and pomegranate peel (PP) were chemically modified with hydrochloric acid and applied as potential adsorbents for the removal of Azure A, one of the products of oxidized methylene blue, from aqueous solutions. The surface chemistry and morphology of the modified grape stalk (H-GS) and pomegranate peel (H-PP) were characterized by FTIR and SEM. The results showed that the adsorption capacity of H-PP was higher than PP, GS and H-GS. The experimental data indicated that PP, H-PP and H-GS displayed Freundlich adsorption properties while GS displayed both the Langmuir and Freundlich adsorption properties. The adsorption kinetic of Azure A for all adsorbents obeys the pseudo-second-order kinetic model. Moreover, the thermodynamic parameters were also determined. © 2017, The National Academy of Sciences, India.