Immobilization of Dithizone on Coal Fly Ash in Alkaline Medium as Adsorbent of Cd(II) Ion

Abstract

Immobilization of dithizone on activated fly ash (AFA) has been carried out in water medium and used as adsorbent for Cd (II) metal. Some parameters that influences the efficiency of Cd (II) adsorption such as solution pH, adsorbent mass, contact time and initial adsorbate concentration were optimized. The concentration of Cd (II) ion before and after adsorption or desorptiom were determined by AAS. Results of the study suggest that immobilization of dithizone on AFA has successfully accomplished in water/base medium. Adsorption of Cd (II) on AFA and dithizone-immobilized fly ash (DIFA) reaches its maximum value at pH 7 and contact time of 60 minutes using 0.02 g of adsorbent mass. Kinetics and isotherm adsorption studies indicate that the adsorption of Cd (II) on both adsorbent follows pseudo 2nd-order kinetics model and Langmuir isotherm adsorption model. Based on desorption data, it is revealed that the interaction between metal ion Cd (II) and AFA is dominated by ion exchange, while the interaction between Cd (II) metal ion and DIFA mostly occurs via the formation of complexes.