Antagonistic Competitive Equilibrium Modeling for the Adsorption of Ternary Metal Ion Mixtures from Aqueous Solution onto Bagasse Fly Ash

Abstract

The present study reports the simultaneous adsorption of cadmium (Cd(II)), nickel (Ni(II)), and zinc (Zn(II)) ions from aqueous solution onto bagasse fly ash (BFA). BFA is a waste material collected from the particulate collection equipment attached to the flue-gas line of bagasse fired boilers in sugar mills. The equilibrium adsorption data were obtained with a BFA dosage of 10 g/dm3 at varying initial concentrations (C0 = 10−100 mg/dm3), 5 h contact time, 30 °C temperature, and initial pH 6. The single metal ion equilibrium adsorption data were fitted to the noncompetitive Langmuir, Freundlich and Redlich−Peterson (R−P) models. The R−P and Freundlich models represent the equilibrium data better than the Langmuir model over 10 ≤ C0 ≤ 100 mg/dm3. The adsorption capacity of Zn(II) is found to be higher than that of Ni(II) or Cd(II) for the ternary metal solutions, and is in agreement with the single-component adsorption data. The equilibrium metal removal decreases with an increase in the concentration of ...