CeO2 modified carbon nanotube electrified membrane for the removal of antibiotics

Electrified carbon nanotube membranes (ECM) are used as electroactive porous materials for the degradation of micropollutants. It integrated design of both electrochemical processes and filtration functions. In this study, CeO2 modified carbon nanotube electrified membrane (CeO2@CNT membrane) was prepared and activate NaClO towards degradation of antibiotics. As CeO2 with face-centered cubic (Fcc) fluorite structure was loaded onto the CNT sidewalls, the CeO2@CNT membrane showed a higher over potential and a smaller equivalent polarization resistance compared to ECM. More reactive oxygen species (ROS) and reactive chlorine species (RCS) were generated by CeO2@CNT membrane due to faster electron transfer at the solid-liquid interface. Thus, the removal efficiencies of DCF, SMX, CIP, TC and CBZ were more than 91.2%, 91.3%, 94.4%, 99.3% and 89.4% by the CeO2@CNT membrane with NaClO, respetively. And the apparent reaction rate constant (k) of the CeO2@CNT membrane was 2.9 times of that of ECM. The selective capping experiments and density functional theory (DFT) calculation showed that the oxygen vacancies of CeO2 contributed to the generation of center dot OH, and the generation of ClO center dot and center dot O-2(-) would mainly occur on Lewis acid sites of CeO2. In addition, the CeO2@CNT membrane showed a reasonable stability to treat actual water samples and reduced disinfection byproducts (DBPs) formation, suggesting that it can potentially be combined with the conventional chlorine disinfection to degrade antibiotics in water.

Automated summary

In this study, a CeO2 modified carbon nanotube electrified membrane (CeO2@CNT membrane) was prepared for the degradation of antibiotics using NaClO. The CeO2@CNT membrane showed a higher reaction rate constant compared to the traditional carbon nanotube electrified membrane and exhibited good stability.