Iron Minerals Mediated Interfacial Hydrolysis of Chloramphenicol Antibiotic under Limited Moisture Conditions

Iron minerals are important soil components; however, little information is available for the transformation of antibiotics on iron mineral surfaces, especially under limited moisture conditions. In this study, we investigated the catalytic performance of four iron minerals (maghemite, hematite, goethite, and siderite) for the hydrolysis of chloramphenicol (CAP) antibiotic at different moisture conditions. All the iron oxides could efficiently catalyze CAP hydrolysis with the half-lives 10 wt % due to the competition of water molecules for surface reactive sites. For siderite, the CAP hydrolysis was resistant to excessive surface water. A bidentate H-bonding interaction mechanism would account for CAP hydrolysis on siderite. The results of this study highlight the importance of surface moisture on the catalytic performance of iron minerals. The current study also reveals a potential degradation pathway for antibiotics in natural soil, which has been neglected before.