Paper No. 6
Presentation Time: 2:45 PM


RUCKS, Melinda J., Dept. of Geography and Geology, Western Kentucky University, Bowling Green, KY 42101 and CELESTIAN, Aaron J., Geography and Geology, Western Kentucky University, 1906 College Heights Blvd, Environmental Science and Technology, Bowling Green, KY 42101,

The relatively rare, microporous hydrated titanosilicate mineral zorite has industrial applications as a highly selective ion exchanger, gas separator, and selective catalyst of organic compounds. We investigate the crystallographic and spectroscopic changes in zorite that occur during rare earth element ion exchange.

We used both static single crystal X-ray diffraction and time-resolved Raman spectroscopy to determine absolute structural geometry and transient structural/molecular conformational changes, respectively. Ion exchange studies were conducted from both the starting sodium form (zorite-Na) and the modified hydrogen form (zorite-H). Zorite was synthetically prepared in the lab and exhibits a structure similar to ETS-4 (Engelhard Titanium Silicate #4).

Results of time-resolved Raman spectroscopy indicate multiple ion exchange steps as yttrium, europium, gadolinium and terbium exchange into the porous framework. The overall exchange dynamics were significantly different for each REE cation tested. In addition, extent and rate of exchange also depended on the form of the starting material (zorite-Na vs. zorite-H).