Adsorption of arsenites and arsenates from aqueous solutions by application of modified natural inorganic materials: A kinetic study

Abstract

Two commercially available adsorbents, white tuff from Strmos region and a material with a commercial name Zeofit obtained from Palanka region, were investigated as possible raw materials for adsorption of arsenites and arsenates from aqueous solutions. These raw materials were modified through chemical insertion of iron within the basic material structure and ionic substitution of calcium and magnesium ions with sodium ions in order to improve the sorptive and ion-exchange properties of studied raw materials. Obtained results from the experimental study of the adsorption of arsenic ions from simulated aqueous solutions suggest that the Zeofit material produced better results than the white tuff material, which showed satisfactory adsorption efficiency only at lower arsenic ions concentrations. Drinking water from the water supply system in Skopje was used for preparation of the studied arsenic ions solutions. Performed kinetic study and resulting kinetic models for both materials, generated a kinetic model of first order for the white tuff material, whereas the Zeofit material adsorption kinetics indicated a pseudosecond order.