High-efficiency adsorption of tetracycline by cooperation of carbon and iron in a magnetic Fe/porous carbon hybrid with effective Fenton regeneration

Highly efficient removal of tetracycline (TC) has been achieved by cooperative adsorption of carbon and iron in a magnetic Fe/porous carbon hybrid (MagFePC) derived from MIL-101(Fe). The optimum hybrid material MagFePC-700 (obtained from MIL-101(Fe) carbonization at 700 °C had a good adsorption capacity for TC at a wide range of pH, and the highest adsorption capacity was up to 1301.24 mg g−1 at a pH of around 7, which was 6 times higher than that of activated carbon. In addition to TC, it also showed high adsorption capacity (>800 mg g−1) for oxytetracycline, chlortetracycline hydrochloride, and tetracycline hydrochloride. The porous carbon in MagFePC-700 was rich in meso- and micropores, which were conducive to the transport and enrichment of TC molecules. Especially, the Fe nanoparticles in the hybrid were found to contribute greatly to the adsorption, which were both the active site of adsorption and the active site of Fenton reaction. A multi-cycle experiment revealed that the MagFePC material was regenerated well through Fenton reaction, and the regeneration conditions were mild without adjusting the pH. Taken it all together, MagFePC-700 is a green and recyclable adsorbent for the removal of antibiotics from water owing to its high adsorption capacity, easy separation, and good reuse performance.