Urea-Functionalized MIL-101(Cr)@AC as a New Adsorbent to Remove Sulfacetamide in Wastewater Treatment

The presence of sulfa antibiotics in water is becoming increasingly serious and actions need to be taken to establish an effective wastewater purification process for their removal. MIL-101­(Cr)@AC was prepared by incorporating activated carbon into the MIL-101­(Cr) framework to reduce unused voids in MIL-101. MIL-101­(Cr)@AC has a high specific surface area and was successfully synthesized and activated with urea. In this study, the adsorptive removal of the sulfonamide antibiotic, sulfacetamide (SA), from wastewater was studied using urea-activated MIL-101­(Cr)@AC for the first time. High SA adsorption efficiency was observed, and an adsorption equilibrium was reached within approximately 60 min. The adsorption kinetics and isotherm records were best fitted using the Langmuir model and a pseudo-second-order model, respectively. Therefore, according to the result of adsorption, a possible mechanism was proposed. Hydrogen bonding between −NH₂ on the grafted urea-MIL-101­(Cr)@AC and −SO₂ groups in SA resulted in an increase in adsorption efficiency. In addition, urea-MIL-101­(Cr)@AC exhibited excellent reusability, which is attractive for potential applications in adsorbing SA from wastewater.