Microorganism-mediated synergistic degradation of antibiotics in wastewater via dual-electric centers
Dissolved organic carbon (DOC) plays a trade-off effect in the transformation of antibiotics. However, how to actively utilize DOC to facilitate antibiotic elimination in biofilter remains a challenge. To address this, we employed a dual-electron centers catalyst (CCN-Cu-Al2O3/Alumina) that carbon-doped graphene-like carbon nitride complexed with Cu-doped Al2O3 loading on commercial alumina in biofilter to treat multiple antibiotics in municipal wastewater without external energy. The biofilter achieves removal efficiencies of 74.6% for ciprofloxacin (CIP) and 96.5% for sulfadiazine (SDZ) alongside a 46.63% reduction in antibiotic resistance genes. Electrons transfer from SDZ and CIP to DOC in the polar DOC-CIP-SDZ complexes. The polar complexes coordinate with pi-system electron-poor region, and its electrons persistently delocalize to Cu sites electron-rich region under Cu-pi electrostatic force, then assimilated by microorganism. The process leads to the cleavage of SDZ and CIP, relieves the stress effect on microorganism. The electron transfer from Cu sites to microorganism promotes the expression of genes associated with the synthesis of extracellular proteins, riboflavin, and e-pili. Concurrently, it enhances exogenous electron-facilitated electrotrophic energy metabolism, such as fumarate reduction and CO2 fixation, optimizing microbial energy structure. This study presents a viable green strategy for sustainable management of water environments.