PHOTOCATALYTIC SOLAR OXIDATION OF ACESULFAME-K. EFFECT OF INITIAL pH, CATALYST DOSE AND OXIDANT CONCENTRATION

Aqueous acesulfame-K was oxidized in a pilot solar photocatalytic reactor, equipped with a compound parabolic collector (CPC). The reactor has an area of 0.40 m2 of CPC collectors with geometrical concentration ratio of 1 and a simple mechanical configuration. The experiments of photocatalytic oxidation of acesulfame-K were performed by treating 2 L of water with an initial concentration of 15 mg/L. The photocatalyst used was P25 (Aeroxide TiO2) from Evonik. One of the goals of the research work was to find a set of conditions to efficiently remove this emerging concern pollutant. Results allowed proposing a set of reaction conditions that lead to a high removal of acesulfame-K. In addition, the experimental design allowed determining the effect of initial pH as well as the impact of initial concentrations of photocatalyst and chemical oxidant. The removal efficiency of acesulfame-K and related UV-absorbing species reached values up to 96-99 % and there was not a quantifiable amount of intermediate products (analyzed as UV absorbing species). Despite reaction time was fixed in 3 h for all the experiments, oxidation efficiencies higher than 95 % were reached at 2 h of reaction or even before.