Degradation of the ciprofloxacin antibiotic by photo-Fenton reaction using a Nafion/iron membrane: role of hydroxyl radicals

Antibiotic pollution in waters is a major health issue that induces antimicrobial resistance and, in turn, the inefficacy of actual antibiotics to cure diseases. There is therefore a need for antibiotic removal from water and wastewater, yet actual remediation techniques are limited. Here, we studied the degradation of ciprofloxacin by the photo-Fenton reaction using a Nafion/Fe 3+ membrane as catalyst, with focus on the effect of hydroxyl (·OH) on membrane stability and recycling. Concentration of ciprofloxacin and ·OH were measured by high-performance liquid chromatography (HPLC). The Nafion membrane was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), attenuated total reflection (ATR) and X-ray photoelectron spectroscopy (XPS). Results show that the Nafion/Fe 3+ membrane degrades ciprofloxacin completely within 4 h. After membrane recycling, degradation efficiency is reduced due to the loss of Fe 3+ ions during membrane regeneration. Moreover, ·OH alters the carbon backbone of the membrane.