Decomposition kinetics of MTBE, ETBE and, TAEE in water and wastewater using catalytic and photocatalytic ozonation

Abstract

The results of an extensive kinetic study on the heterogeneous ozonation of three different fuel-oxygenates: Methyl-t-butyl-ether (MTBE), ethyl-t-butyl-ether (ETBE) and t-amyl-ethyl-ether (TAEE), over an immobilised TiO2 layer in dark (catalytic ozonation) and in the presence of UVA irradiation (photocatalytic ozonation) are shown in the present paper. A falling film reactor was utilised to handle the oxidation processes in this work. The study was conducted in both deionised water and a real wastewater sample. The decomposition of the three chosen model compounds showed good agreement with pseudo first-order kinetics using both catalytic and photocatalytic ozonation in water and wastewater. The increase of ozone concentration and the concentrations of MTBE, ETBE and TAEE in their aqueous solutions led to a linear increase in the initial removal rates of these compounds by photocatalytic ozonation. The removal rates of MTBE, ETBE and TAEE by photocatalytic ozonation were about 10 times, 2.5 times and 2.2 times more than those by catalytic ozonation, respectively. The determined reaction rate constants of MTBE, ETBE and TAEE with ozone were 0.231M−1s−1, 0.785M−1s−1 and, 0.960M−1s−1, respectively. The determined adsorption level of model compounds on the photocatalyst surface was in the following order: MTBE>ETBE>TAEE.