Study of a photocatalytic process for removal of antibiotics from wastewater in a falling film photoreactor: Scavenger study and process intensification feasibility

Abstract

This study focused on the removal of antibiotic by coupling of heterogeneous photocatalysis with ozonation and hydrogen peroxide. The main objective was to intensify the efficiency of photocatalytic activity for better and faster antibiotic elimination/mineralization in wastewater. To fulfill this purpose a photocatalytic process based on falling film reactor was designed and optimized. The effects of operating parameters such as wastewater flow rate in the falling film reactor, the presence of an oxidizing agent (H2O2 and O3), inlet concentrations, including catalyst dosage and light intensity were investigated and discussed. Experiments were mainly conducted with Flumequine and Clarithromycin. The first molecule (Flumequine) will serve as an example of fluoroquinolone antibiotics and the second (Clarithromycin) as an example of macrolide antibiotics. Experimentally, the results have shown interesting degradation and mineralization efficiency (on the order of 94% for degradation and 76% for mineralization). Evidence for redox catalysis was shown using X-ray photoelectron spectroscopy (XPS) before and after pollutant degradation. Moreover, special attention was also paid to identify the reaction products and the plausible degradation pathway during Flumequine degradation.