Structural comparison of two iron-bearing clays using infrared spectroscopy

CHED 1132

Bryan Richard Bzdek, bbzdek@bucknell.edu and Molly M. McGuire, mmcguire@bucknell.edu. Department of Chemistry, Bucknell University, Lewisburg, PA 17837
Attenuated total internal reflection Fourier-transform infrared spectroscopy (ATR-FTIR) was used to compare changes in the structures of two hydrothermal nontronite clays as they were reduced. NAu-1 is a bright yellowish-green clay containing Fe3+ in only the octahedral sheet; NAu2- is a dark brown clay containing Fe3+ in both the octahedral and tetrahedral sheets. Oriented clay films were studied under plane polarized light in order to qualitatively determine changes in the orientation of OH and Si-O bonds as the iron in each was reduced. The results of this study aid in understanding the role of tetrahedral iron and changes in clay structure upon reduction.