Photocatalytic degradation of methyl-tert-butyl ether in TiO2 slurries: A proposed reaction scheme

Among the various alternatives to enhance the octane rating of gasoline, methyl-tert-butyl ether (MTBE) has become increasingly the compound of choice. Due to its high solubility in water there are some environmental concerns related to the remediation of waters contaminated with gasoline containing MTBE. Although MTBE is difficult to treat economically with conventional techniques, it has been found to be readily degraded photocatalytically. In batch TiO2 slurries and under the experimental conditions used in these experiments MTBE degradation proceeded with an initial pseudo first-order rate constant of 1.2 • 10−3 s−1. The primary by-products of this reaction have been identified as t-butyl formate and t-butyl alcohol, both of which are also readily degraded photocatalytically, albeit at slightly slower rates than MTBE. Mass balance calculations have shown that MTBE is virtually completely mineralized and a reaction scheme is proposed.