Wednesday, November 4, 2009
Convention Center, Exhibit Hall BC, Second Floor
Biomaterials, such as crop residues and dead fungal
biomass, have been demonstrated to be capable of reducing Cr (VI) to Cr (III).
However, little is known about the mechanisms of Cr(VI) reduction by the biomaterials because of their
complex compositions. Therefore, the aims of this work were to investigate the
sorption and reduction of Cr(VI) on
lignin, cellulose, hemicellulose and chitin, which
are the main components of biomaterials. The materials before and after Cr(VI) reaction were analyzed using FTIR, 13C NMR and SIMS to identify
the functional groups governing Cr (VI)
reduction on these materials. Cr K-edge XAS was applied to determine the
oxidation states and structures of Cr on the sorbents.
The results showed that lignin possessed a high Cr(VI) reduction capacity due to its aromatic nature. Hemicellulose and chitin can also reduce Cr(VI) to Cr(III)
while Cr(VI) reduction by cellulose was
not observed. The differences in the Cr(VI)
reduction capabilities of these aliphatic structures result from the
differences in their functionalities. Therefore, the functional groups
of these material play a key role in Cr(VI)
reduction as well as the sorption of resultant Cr(III).