Porous structured MIL-101 synthesized with different mineralizers for adsorptive removal of oxytetracycline from aqueous solution

Abstract

In this work, highly porous MIL-101 materials using hydrochloric acid (HCl) or hydrofluoric acid (HF) as a mineralizer were synthesized. The products were characterized with X-ray diffraction, scanning electron microscopy, thermal gravimetric analysis, and N₂ sorption analysis. The results proved that the mineralizers had an obvious effect on the microstructures and morphologies of MIL-101, and MIL-101(HCl) showed remarkable superiority in a higher specific surface area, smaller particle size and higher crystallinity to the HF counterpart. These materials were then used to adsorb and remove the oxytetracycline (OTC) antibiotics from a water solution and an effective fast adsorption of OTC in aqueous solution was observed in the adsorptive kinetics. Compared with MIL-101(HF), a higher adsorption capacity on the MIL-101(HCl) was obtained, which was probably attributed to the higher specific surface area for the MIL-101(HCl). The adsorption mechanism might be greatly ascribed to π–π interaction, and acid–alkaline interaction between the oxytetracycline molecule and the adsorbent.