Removal of Pb²⁺ and Cd²⁺ ions from aqueous solutions using Fe₃O₄/Bentonite nanocomposite

Abstract

The paper presents results of studies on using Fe₃O₄/bentonite nanocomposite (FB) to clean water contaminated by Pb²⁺ and Cd²⁺ ions. With the advantages of cheap and abundant bentonite as well as convenient magnetic separation, the using of FB is expected to reduce water treatment expenses. The batch experimental results indicated that the pH of the solution, the initial metal ion concentration and the contact time play important roles in the adsorption process of Pb²⁺ and Cd²⁺ ions onto the FB. The results from adsorption isotherm study are found to fit well with Freundlich adsorption isotherm model. In the adsorption condition: adsorbent dose of 1mg.L⁻¹, initial concentration of 100 mg.L⁻¹, contact time of 60 min at 120 rpm and at 25°C, the adsorption capacity for Pb²⁺ and Cd²⁺ ions is 84.9 mg.g⁻¹ and 58.6 mg.g⁻¹, respectively. These values of FB material are higher than one of most of the other materials. It is promising that this FB nanoeomposite would become an efficient and economic material for Pb²⁺ and Cd²⁺ ions removal in the practical environmental remediation.