Kinetic analysis on the combined use of photocatalysis, H2O2 photolysis and sonolysis in the degradation of methyl tert-butyl ether

Photocatalysis on TiO2, with irradiation wavelength 254 nm or 315- 400 nm, and sonolysis at 20 kHz were employed, either separately or simultaneously, or in the presence of hydrogen peroxide, as advanced oxidation techniques in the degradation of methyl tert-butyl ether (MTBE) in water under atmospheric conditions. MTBE generally underwent degradation according to a first-order rate law. The prevailing reaction paths were identified by monitoring the time profile of the main reaction intermediates (acetone, tert-butyl formate and tert-butyl alcohol). Hydroxyl radicals, able to attack both MTBE and its degradation intermediates, played a central role in all degradation conditions. The highest degradation and mineralization efficiency, in terms of both treatment duration and energy consumption, was achieved under hydrogen peroxide photolysis at 254 nm.