Photocatalytic degradation of ciprofloxacin & norfloxacin and disinfection studies under solar light using boron & cerium doped TiO2 catalysts synthesized by green EDTA-citrate method

Abstract

The presence of antibiotic residues in water bodies is an emerging global concern due to its potential development of antimicrobial resistance. Hence, it is essential to develop photocatalysts that not only degrade the antibiotics but can also simultaneously disinfect. Four different boron and cerium doped TiO2 photocatalysts, synthesized by the EDTA-citrate method, are studied for the degradation of two common fluoroquinolone-based antibiotics: ciprofloxacin (CIP) and norfloxacin (NOR) under sunlight. The catalysts are characterized by SEM, TEM, Raman spectroscopy, XPS, DRS, BET surface area and particle size analyzer. At optimized conditions, the synthesized catalysts showed 90–93% degradation for both CIP and NOR. The effects of catalyst loading and initial concentration are studied, and the reaction is found to be pseudo-first-order. The degradation is analyzed by COD reduction and LC–MS, and the by-products of degradation determined. The recycle studies showed that the catalysts are stable up to three consecutive runs. The scavenging experiments indicated e― and OH˙ as the dominant species responsible for the photocatalytic activity. The disinfection studies using these catalysts under solar light gave 95–99.99% efficiency for E.coli confirming that they are very efficient and can be further exploited for large scale treatment. © 2020 Elsevier B.V.