Red mud supported on rice husk biochar as sono-photo-Fenton catalysts for degradation of ciprofloxacin in water

To develop efficient methods to reuse red mud and rice husk waste to remove ciprofloxacin (CIP) in water, a simple and efficient Fenton catalyst based on red mud/rice husk biochar composite (RMR) was prepared using ultrasonic-assisted impregnation method. The effects of initial solution pH, initial CIP concentration, contact time, and catalyst dose on the removal of CIP in water were studied. The results showed that at pH 3, RMR dose of 1.0 g/L, CIP concentration of 20 mg/L, treatment time of 180 min, and temperature of 50 °C, the degradation efficiency was the highest at 75.97 % for sono-Fenton (SF) and 95.65 % for sono-photo-Fenton (SPF) with in situ generation of H2O2 during processes, indicating RMR has a great potential application in the treatment of organic pollution in actual wastewater. Other factors such as the co-existing anions (NO3–, SO42−, Cl−) or water matrices and other antibiotics were also investigated to prove the good removal of CIP by RMR for practical applications.