Homogeneous and heterogeneous photo-Fenton degradation of antibiotics using an innovative static mixer photoreactor

•NETmix® is a feasible alternative as photo-Fenton reactor.•Fe2O3-TiO2 film shows high efficiency for degradation of antibiotics.•Fe2O3-TiO2 film stabilize with reuse without a significant photo-activity loss.•Leached Fe adds to the antibiotics' removal by a homogeneous photo-Fenton route.

The use and disposal of antibiotics results in their release in large quantities to the environment, posing serious threats to human and ecological health. In the present work, two different conceptual photoreactors are tested for the treatment of recalcitrant aqueous solutions containing three common antibiotics (ciprofloxacin, sulfamethoxazole and trimethoprim). In a first stage, NETmix®, a novel static mixer photoreactor, is compared against the conventional compound parabolic collector (CPC) under homogeneous photo-Fenton treatment conditions. In a second stage, commercial Fe2O3, as well as sol-gel synthesized Fe2O3, TiO2 and Fe2O3-TiO2 composites, are used in the form of films for catalyst screening experiments in a heterogeneous photo-Fenton like treatment. The highest efficiency was obtained with the Fe2O3-TiO2 catalytic film, that was then tested in the NETmix® photoreactor. A conversion of antibiotics higher than 60% (in terms of carbon content) was achieved in three consecutive utilizations of the same Fe2O3-TiO2 film. The used materials were thoroughly characterized by microscopic and spectroscopic techniques.

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