Adsorption of Cd2+ on Carboxyl-Terminated Superparamagnetic Iron Oxide Nanoparticles

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• 作者：Zhange Feng ; Shun Zhu ; Denis Ricardo Martins de Godoi ; Anna Cristina S. Samia ; Daniel Scherson
• 刊名：Analytical Chemistry
• 出版年：2012
• 出版时间：April 17, 2012
• 年：2012
• 卷：84
• 期：8
• 页码：3764-3770
• 全文大小：343K
• 年卷期：v.84,no.8(April 17, 2012)
• ISSN：1520-6882

文摘

The affinity of Cd²⁺ toward carboxyl-terminated species covalently bound to monodisperse superparamagnetic iron oxide nanoparticles, Fe₃O₄(np)-COOH, was investigated in situ in aqueous electrolytes using rotating disk electrode techniques. Strong evidence that the presence of dispersed Fe₃O₄(np)-COOH does not affect the diffusion limiting currents was obtained using negatively and positively charged redox active species in buffered aqueous media (pH = 7) devoid of Cd²⁺. This finding made it possible to determine the concentration of unbound Cd²⁺ in solutions containing dispersed Fe₃O₄(np)-COOH, 8 and 17 nm in diameter, directly from the Levich equation. The results obtained yielded Cd²⁺ adsorption efficiencies of 20 渭g of Cd/mg of Fe₃O₄(np)-COOH, which are among the highest reported in the literature employing ex situ methods. Desorption of Cd²⁺ from Fe₃O₄(np)-COOH, as monitored by the same forced convection method, could be accomplished by lowering the pH, a process found to be highly reversible.