The Removal of Cadmium, Cobalt, and Nickel by Adsorption with Na-Y Zeolite

The article aims to study the removal of heavy metal ions Cd۲+, Co۲+, and Ni۲+ from an aqueous solution using faujasite NaY. The adsorption studies were carried out in the single and binary component system. Sorption experiments were performed in batch at pH (۵–۶), adsorbent dosage (۰.۱۵ g), and initial concentration (۰.۱–۱۰ mmol/L). The single-ion equilibrium adsorption data were fitted to three isotherm models: Langmuir, Freundlich, and Dubinin-Radushkevich. Results showed that the Langmuir isotherm fits sorption data better than the Freundlich equation. The maximum adsorption capacities (Qmax) were ۰.۸۱, ۰.۸۵ and ۰.۹۲ mmol/g for Cd۲+, Ni۲+ and Co۲+ ions, respectively. Besides, the study of the competitive sorption of ions in a binary system showed that faujasite NaY preferentially adsorbs cations in the following order: Co۲+>Ni۲+>Cd۲+. The obtained RL (separation factor or Langmuir parameter) values were in the range of ۰–۱ indicating that Cd۲+, Co۲+, and Ni۲+ sorption were favorable. The obtained mean free energy value for adsorption of Co۲+ and Ni۲+were in the range of ۸–۱۶ kJ/mol, indicating that ions were uptaken through an ion exchange process.

کلیدواژه ها:

Faujasite NaY ، Competitive adsorption ، heavy metals ، Isotherm modeling