abstract
- Ozonation is wastewater treatment use for the degradation of recalcitrant pollutants such as pharmaceutical compounds; however, the kinetic characterization and transformation pathway analysis remain partial for complex medicinal mixtures. The ozonation of commercial pharmaceutical formulation containing ambroxol and dextromethorphan (Histiacil ® NF) was analyzed at laboratory scale under controlled semi-continuous operational conditions. The wastewater treatment efficiency was evaluated through UV-Vis spectroscopy, BOD¿ variation, electrical conductivity measurements, and HPLC analysis for identification an quantification of final reaction products. Ozonation achieved up to a 95 % decomposition of Histiacil® NF within 15 minutes, as demonstrated by UV¿Vis absorbance decline at characteristic wavelengths and confirmed by HPLC analysis. The progressive increase in BOD¿ and electrical conductivity indicated the conversion of the initial molecules of ambroxol and dextromethorphan into smaller, more polar, and potentially biodegradable species. Oxalic acid was identified and quantified as the main accumulated final product by HPLC analysis, which concentration obtained was consistent with stoichiometric predictions. A kinetic model based on pseudo-first-order was established to define both the decomposition of dextromethorphan and the formation and consumption of oxalic acid. The results demonstrate that ozonation is an effective and reproducible treatment strategy for complex pharmaceutical mixtures and highlight the relevance of kinetic modeling as a predictive tool for process optimization and scale-up in water and wastewater treatment applications.