Photo-Degradation of Amoxicillin, Streptomycin, Erythromycin and Ciprofloxacin by UV and UV/TiO2 Processes. Evaluation of Toxicity Changes Using a Respirometric Biosensor

Abstract

Current research aims to conserve natural resources, especially water. Our study focuses on developing water purification to remove contaminating antibiotics using heterogeneous photo-catalysis. We compare photolysis with and without TiO2 catalysis, testing the photo-stability of four representative antibiotics: Amoxicillin, streptomycin, erythromycin and ciprofloxacin by HPLC using a Perkin Elmer 2000 chromatograph, BIO-RAD Bio-sil ODS-5S L 250 mm × 4 mm ID C18 reversed phase column and Perkin Elmer LC-90 UV detector. Both obeyed first order reaction kinetics, usually following the Lagmuir-Hinshelwood model. A respirometric biosensor was employed to assess the toxicity of drug solutions and photo-degradation products. We demonstrate that catalysis consistently decreases toxicity more effectively in all cases. The photo-degradation of ciprofloxacin and amoxicillin took longer.