AVS 49th International Symposium
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP21
Perchlorate Reduction on Irradiated Titania Studied by LITD-FTMS, XPS, and IC

Tuesday, November 5, 2002, 5:30 pm, Room Exhibit Hall B2

Session: Surface Science Poster Session
Presenter: K.D. Lormand, University of California-Davis
Authors: K.D. Lormand, University of California-Davis
D.P. Land, University of California-Davis
E.L. Pyatt-Rudolph, University of California-Davis
Correspondent: Click to Email
Inorganic 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 effects on the human thyroid, long residence time in water sheds, and resistance to existing catalysts used in water treatment. However, preliminary studies have shown that oxidized surfaces of titanium exposed to ultraviolet radiation reduce perchlorates in aqueous solutions effectively. The reaction mechanism of this reduction has been studied using laser induced thermal desorption- Fourier transform mass spectroscopy, x-ray photoelectron spectroscopy, and ion chromatography. A new chamber that allows for the rapid introduction of samples reacted in aqueous solution into UHV for analysis was used for the LITD-FTMS studies. Reacting the perchlorate solutions with the titania catalyst at atmospheric pressures allows for a more inclusive reaction mechanism due to the incorporation of atmospheric water, carbon dioxide, nitrogen, and oxygen. Surface species are seen both in the LITD-FTMS experiments as well as in the XPS studies, while species that do not adhere to the catalyst surface can be seen in the IC solution studies. Studies show that LITD-FTMS of perchlorate and its oxy-chloride derivatives do not have distinct enough fragmentation patterns to be studied by LITD-FTMS. XPS and IC studies have indicated that titania, in a thin film form, is a slow, but effective catalyst for the reduction of perchlorate. Higher surface area titania, like nano-particulate titania, may prove faster in the reduction of perchlorate to chloride.