A green hydrothermal synthesis of polyacrylonitrile@carbon/MIL-101(Fe) composite nanofiber membrane for efficient selective removal of tetracycline

Developing highly efficient, low-cost and reusable adsorbents toward antibiotics is a great challenge for the treatment of wastewater. Here, a polyacrylonitrile@carbon/MIL-101(Fe) composite nanofiber membrane (PAN@C/MIL-101(Fe)) has been prepared for the first time via the combination of electrospinning technique and green hydrothermal method and showed a high adsorption performance toward tetracycline (TC). The MIL-101 (Fe) nanocrystals were uniformly grown in-situ on the surface of activated hydrothermal carbon coated electrospun PAN nanofiber membrane. The incorporation of hydrothermal carbon and MIL-101(Fe) in nanofiber membrane obviously enhanced its adsorption ability. The adsorption process followed pseudo-second-order kinetic model and Freundlich isotherm model, with an adsorption capacity of 392.64 mg/g for TC. Moreover, the PAN@C/MIL-101(Fe) exhibited high selectivity and good regenerability, and the removal efficiency remained above 94% after five cycles. After the real wastewater filtration experiment, chemical oxygen demand (COD) concentration of TC significantly decreased from 155.55 mg/L to 51.84 mg/L, which is below the standard of wastewater discharge (GB 21904-2008). This study provides a promising green strategy for uniform MOFs modified carbon coating nanofiber membrane adsorbent, which has potential application in practical antibiotic wastewater treatment.