IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Surface Science Thursday Sessions
       Session SS3-ThP

Paper SS3-ThP16
Reactions of Perchlorate on Titanium/Titanium Oxide Surfaces Studied by LITD/FTMS.

Thursday, November 1, 2001, 5:30 pm, Room 134/135

Session: Surface Reactions Poster Session
Presenter: K.D. Lormand, University of California, Davis
Authors: K.D. Lormand, University of California, Davis
D.E. Hunka, University of California, Davis
D.P. Land, University of California, Davis
Correspondent: Click to Email
Organic contaminants in water supplies have been a concern for decades, due to possible deadly health effects. Perchlorates, in particular, have posed a major concern as of late due to their irreversible and damaging affects on the human thyroid,@footnote 1@ long residence time in water sheds, and resistance to existing catalysts used in water treatment.@footnote 2@ Catalysts, such as palladium, iron, and platinum, have been found to be quite effective in reducing the concentration levels of most halocarbon residues, but are ineffective on perchlorates. However, preliminary studies of oxidized surfaces of titanium exposed to ultraviolet radiation have been seen to reduce perchlorates in aqueous solutions effectively. Reaction mechanisms of many halocarbon residues on palladium and platinum catalysts have already been elucidated using laser induced thermal desorption and conventional thermal desorption with FT mass spectrometry (LITD/FTMS) on clean surfaces in ultra high vacuum (UHV). Though these studies reveal accurate reaction mechanisms, they are done in an ultra clean environment and do not fully incorporate atmospheric gases into the equation. We have recently designed a new LITD/FTMS chamber to allow the rapid introduction of samples from reaction in aqueous solution into UHV for analysis. This allows for more inclusive reaction mechanisms to be determined due to the incorporation of atmospheric water and oxygen. The reaction of perchlorate is investigated on both titanium metal as well as titanium oxide using LITD/FTMS. While titanium itself is less reactive, the oxides show increased activity and studies of varying oxide layers are presented. @FootnoteText@ @footnote 1@ Siglin, J.C.; Mattie, D.R.; Dodd, D.E.; Hildebrandt, P.K.; Baker, W.H. Toxicol. Sci. 2000, 57(1), 61-74. @footnote 2@ http:/www.epa.gov/ogwdw000/ccl/perchlor/perchlo.html .