LAUSR

Abstract The application of photocatalysis, single, catalytic and photocatalytic ozonation was evaluated for the abatement of a mixture of seven insecticides at pilot plant scale to infer the effect of the reactor’s diameter on the process performance. Two different heterogeneous catalysts were used, a laboratory produced (N-TiO2) compared to the benchmarked P25. The photocatalyst P25 presents best performance comparing with N-TiO2 on the insecticide’s abatement for the different technologies applied. Photocatalytic oxidation and ozonation using the highest tube diameter were capable to degrade almost 100% of the initial insecticide’s concentration. The tube diameter has high impact on the required catalyst amount for the photocatalytic oxidation process. The photocatalytic oxidation with P25 for low diameter tube (32 mm) achieved almost 90% of global insecticides degradation with QUV = 25 kJ/L and 200 mg/L of catalyst while for larger tube was achieved the same degradation with only QUV = 8.2 kJ/L and 100 mg/L of catalyst. Moreover, photocatalytic ozonation improved N-TiO2 performance leading to about 65% of global insecticides mixture degradation while photocatalytic oxidation was only able to obtain 35%. However, the impact of ozone on the P25 photocatalytic activity was almost negligible due to the high efficiency of this catalyst under solar radiation.