Displacement Investigation of Nanostructure Complex Immobilized on Gold Surface Using Spectroscopy and Electrochemical Methods

Displacement of Fe(III), accumulated by deferrioxamine immobilized on the gold surface carpeted by mercaptopropionic acid (Au-MPA-DFO), with Zr(IV) and Hf(IV) ions from solution phase is investigated. The process is followed and supported by several techniques including attenuated total reflectance Fourier transform infrared spectroscopy, energy dispersive x-ray diffraction microanalysis, ultraviolet visible spectroscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. The results show that the DFO ligand can accumulate and complex the M (Fe(III), Hf(IV), and Zr(IV)) ions on the Au-MPA surface by different affinities; Thus, it is concluded that DFO can be used to identify and differentiate the behaviors of these two important heavy metal ions. To our knowledge, this is one of the few cases in which Hf(IV) and Zr(IV) ions show different behaviors. Furthermore, the new Au-MPA-DFO-M(IV) complexes, formed in the Fe(III)/M(IV) replacement reaction, have different surface morphologies and nano-structures.