A new study on photocatalytic degradation of meropenem and ceftriaxone antibiotics based on sulfate radicals: Influential factors, biodegradability, mineralization approach

The removal of meropenem and ceftriaxone antibiotics from solution, as first study, was performed in a photo Fenton process in which UV light and ferrous ions (Fe2+) were applied as persulfate (PS) activators. The batch tests were performed in various conditions like pH of aqueous solution (2-10), amounts of ferrous (0.1-0.5 g/L), initial antibiotic concentrations (20-100 mg/L), persulfate dosages (1-5 mM), UV light intensities (4, 6 and 8 W), temperatures (20, 35 and 50 degrees C) and scavengers (TBA and IBA). Based on the results of comparative studies, PS/Fe2+/UV system showed the highest ability to remove both antibiotics, in comparison with the other processes (i.e., UV, PS, PS/UV and PS/Fe2+). In addition, the removal rate of antibiotics has a direct relationship with the iron and PS concentrations, UV light intensity and temperature. While, increasing pH of solution and initial antibiotic concentrations, the removal rate of antibiotics witnessed a significant decline. Quenching tests indicated that sulfate radicals had a dominant species during degradation reactions. The mineralization higher than > 54% was obtained for both antibiotics. A slight loss was observed in the degradation efficiencies of antibiotics in binary system, compared to the single one. The experimental data were in good agreement with pseudo-first-order kinetic model. Biodegradability indices were enhanced significantly after treatment, which demonstrates that PS/Fe2+/UV system has a high ability in removing organic matters effectively. Finally, it can be inferred that the integration of ferrous ions and UV irradiations was an appropriate technique for efficient activation of PS, which can be introduced as a promising method to remove high concentrations of antibiotics in a real wastewater sample which shows its high feasibility in natural environment.