Amoxicillin Degradation by TiO2 P25 Solar Heterogeneous Photocatalysis: Influence of pH and Oxidizing Agent H2O2 Addition

Abstract

Over the years, there has been an increase in the consumption of drugs, particularly antibiotics. Amoxicillin (AMX) is considered one of the most widely used antibiotics, causing resistance in microorganisms in the ecosystem where it is found. Additionally, it has been cataloged among the drugs under surveillance by the European Commission since 2020. The present work studies the efficiency of AMX degradation by photolysis and heterogeneous solar photocatalysis processes under different reaction pH levels (3.5, 4.15, 7 and 9) and observing the influence of different doses of H2O2 (nil and 4 mM), as an oxidizing agent. TiO2 P25 was used as photocatalyst, impregnated in glass supports of 0.1 and 1 m2 in flat plate reactors (FPR). A 2 × 2 × 4 statistical analysis carried out after repeated measurements to determine the relationship between the different parameters involved (process, H2O2 dose, and pH). The kinetics of the AMX degradation reaction showed the best rate constant (KphC = 0.10 min−1) under acidic medium conditions (pH 4.15), without addition of H2O2, and by heterogeneous photocatalysis when using a 1 m2 FPR to achieve 100% COD removal. ANCOVA showed significant differences (p < 0.05) in the use of H2O2 for the first minutes of the reaction and in the different FPR surfaces.