ADSORPTION OF Zn 2 Cd 2 AND Cu 2 ON ZEOL

Adsorption of copper, cadmium and zinc on manganese and iron oxide coated zeolite from aqueous solution was investigated in a batch mode. Experiments were conducted to investigate the effects of the initial concentration of metals, initial pH, contact time and temperature on the adsorption of ions. According to the results, adsorption of ions on manganese and iron oxide coated zeolite increased with the enhancement of initial Cu²⁺, Zn²⁺ and Cd²⁺ concentrations and contact time and also with increase of temperature. The results showed that at the beginning, the adsorption rate of Cu²⁺ and Cd²⁺ was more than 90 %. This rate continued to be slower for Zn²⁺ in both zeolites. Furthermore, the amount of Cu²⁺, Zn²⁺ and Cd²⁺ adsorption on the manganese oxide coated zeolite (qₑ) was equal to 14 mg/g, 9 mg/g and 16 mg/g and on the iron oxide coated zeolite it was 11 mg/g, 7 mg/g and 13 mg/g, respectively. It was shown that at the concentrations below 100 mg/dm³ adsorption was rapid and almost all heavy metals were adsorbed. As a result, the significant factor affecting qₑ is the proportion of weight to liquid and pH in the solutions. Finally, the results showed that the adsorption of Zn²⁺, Cu²⁺ and Cd²⁺ onto the manganese oxide coated zeolite followed both the Langmuir and Freundlich isotherm models.