Mechanism of Pb(II) Biosorption by Saccharomyces Cerevisiae

The mechanism of Pb ( II ) biosorption by Saccharomyces Cerevisiae is investigated by scanning electron microscopy-energy dispersive x-ray (SEM-EDX) spectroscopy, Fourier transform infrared(FTIR) spectroscopy and x-ray photoelectron spectroscopy(XPS). The SEM figures show that the shapes of Saccharomyces Cerevisiae cells doesn\´t obviously change after the adsorption,but there are many "spots" on the cell walls, which indicates the cell walls of Saccharomyces Cerevisiae play an important role in adsorption process. The EDX spectrum analysis helps to substantiate the interactive adsorption between Pb ( II ) and K ( I ) on the cell surfaces. FTIR analysis indicates that COOH, C=O, C-O and N-H are the main active binding sites for the process of adsorption. XPS analysis further reveals that Pb ( II ) combines with some active functional groups containing the elements of C, N, O and P. Therefore, the mechanism of saccharomyces cerevisiae adsorption on Pb(II) has mainly resulted from both the ion exchange and the surface complexation.