Novel functionalized metal-organic framework MIL-101 adsorbent for capturing oxytetracycline

Developing high-performance materials for removal of antibiotics has attracted ever-increasing concerns since variety of harmful antibiotics have been frequently detected in aquatic environments and posed a serious threat to both human health and ecosystems in recent years. In this work, a novel adsorbent (ED-MIL-101) for oxytetracycline antibiotic (OTC) was prepared by grafting ethylenediamine (ED) to Lewis acidic open metal sites in porous metal-organic framework MIL-101. The successful grafting was corroborated via FT-IR spectrum. Compared with the pristine MIL-101, ED-MIL-101 demonstrated a slight decrease in BET surface areas and pore sizes, while the basic frameworks remain invariant. Results for kinetics and thermodynamics showed that the aminofunctionalized adsorbent exhibited a predominant superiority over nongrafted MIL-101 and activated carbon (AC) on the removal of OTC, even though the specific surface area decreased remarkably after grafting. Moreover, ED-MIL-101 can be regenerated by simple washing with ethanol and reusable up to at least the third run with little change in adsorption capacity . Evidence from zeta potential showed that the adsorption of OTC was also driven by electrostatic interaction between the OTC and ED-MIL-101. These results indicate that ED-MIL-101 has great potential in removing OTC contaminant from water.