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NOVEL EMBEDDED CERAMIC ELECTRODE SYSTEM TO ACTIVATE NANOSTRUCTURED TITANIUM DIOXIDE FOR DEGRADATION OF MTBE
Kim, C., E SahleDemessie*, AND P. Biswas. NOVEL EMBEDDED CERAMIC ELECTRODE SYSTEM TO ACTIVATE NANOSTRUCTURED TITANIUM DIOXIDE FOR DEGRADATION OF MTBE. Presented at 228 American Cemical Society National Meeting, Philadelphia, PA, August 22 - 26, 2004.
To inform the public
A novel reactor combining a flame-deposited nanostructured titanium dioxide film and a set of embedded ceramic electrodes was designed, developed and tested for degradation of methyl tert-butyl ether (MTBE) in water. On applying a voltage to the ceramic electrodes, a surface corona was generated which provided sufficient light to activate the nanostructured titanium dioxide film. Furthermore, air passed above the ceramic electrodes could be ozonized and bubbled through the reactor to enhance MTBE degradation. The concentration of ozone formed was controlled by adjusting the applied voltage and supplying either pure oxygen or air. While the reactor could be operated in continuous mode, all kinetic runs were made in a batch mode without a pH buffer.
The results reveal typical first-order decay: with an initial MTBE concentration of 10 mg/L, 98% of MTBE was degraded within 3 hours. The combined ozone and UV-activated titanium dioxide photooxidation of MTBE exhibited pseudo first-order kinetics (R2=0.996). The rate constant was 0.78/hr (=2.17 x 10-4/sec) with an initial MTBE concentration of 10 mg/L and was 2.0/hr (=5.56 x 10-4/sec) with an initial concentration of 100 mg/L. Tert-butyl alcohol and tert-butyl formate were found to be the primary intermediates and a small amount of acetone was detected. The concentrations of the intermediate by-products increased until 1.5 to 2 hours, after which they decreased and were completely converted to carbon dioxide.