Application Of Photoelectric Synergistic Fenton-like System In The Treatment Of Ciprofloxacin Wastewater

Ciprofloxacin（CIP）,as a fluoroquinolone antibiotic,has been widely used in the treatment of diseases caused by bacterial infection because of its broad-spectrum antibacterial activity and excellent bactericidal effect.However,CIP ingested by human or animal can not be completely absorbed,and the unabsorbed CIP will be excreted out of the body through feces or urine,which causes serious pollution to the environment.At present,CIP has been detected in surface water,groundwater and even drinking water.Since CIP residues in water can induce antibiotic resistance genes even at low concentrations,the abuse of CIP has posed a serious threat to ecological environment and public safety.In this paper,a novel Fe-free photo-electro-Fenton-like（PEF）system was designed to remove the CIP in water with the catalysis of MnO_x/g-C₃N₄ or Cu₂O/Bi₂Mo O₆.The MnO_x/g-C₃N₄ and Cu₂O/Bi₂Mo O₆ composites possessed good catalytic effect on CIP degradation,and the MCN（1:6）and CBMO-25%showed the best catalytic performance.With the catalysis of MCN（1:6）and CBMO-25%,the degradation efficiency of CIP were 96.23%and 97.61%in 120 min,respectively.The TOC removal efficiency were 80.02%by MCN（1:6）in 240 min and 43.60%by CBMO-25%in 120min.The results of XRD and FT-IR confirmed the successful preparation of these two composites and XPS tests showed the existence of multivalent metal ions in the catalyst.MCN（1:6）and CBMO-25%could not only generate·O₂^-and h⁺through the photocatalytic process,but also decompose H₂O₂ into·OH by manganese ions or copper ions with different valence.And the photo-generated electrons could also promote the decomposition of H₂O₂ into·OH.Therefore,the photoelectric synergy system was helpful to stimulate a variety of active species,which could promote the rapid degradation of CIP.The results of UV-vis DRS,PL and photoelectrochemical tests showed that MCN（1:6）and CBMO-25%possessed the strongest light absorption ability,the lowest charge transfer resistance,the fastest charge separation and transfer rate.Therefore,compared with the single MnO_x,g-C₃N₄,Cu₂O and Bi₂Mo O₆,the composite material had the best photoelectric performance.Compared with the traditional Fenton reaction,the p H range of PEF system was widened in degradation of CIP.The cyclic experiments of CIP degradation showed that the PEF system possessed good stability under the catalysis of MCN（1:6）and CBMO-25%.PEF system provided a new way to remove CIP in water environment.