Titanium metal–organic framework-derived nanocrystalline TiO2-supported nitrogen-doped carbon nanostructures as highly efficient antibiotic adsorbents

Abstract

Metal-organic frameworks (MOFs) are explored extensively as a distinctive precursor for producing porous metal oxide-supported nitrogen-doped carbon nanomaterials. MOF-derived materials can offer tailored porosity, structure, and elemental composition so they are gaining prominence as a new-generation adsorbent for emerging antibiotic contaminant removal in aqueous solutions. In this study, we demonstrate the fabrication of nanocrystalline titanium dioxide-supported nitrogen-doped carbon nanostructures (TiO2@NC) obtained from a titanium metal–organic framework (NH2-MIL-125(Ti)) as a starting precursor. When applied as an adsorbent, TiO2@NC nanospheres efficiently removed high concentrations of tetracycline (TC) in aqueous solutions. The TiO2@NC adsorption process obeyed the Langmuir model and pseudo-second-order kinetics. The optimum adsorption capacity of the TiO2@NC nanospheres is estimated to be 1187.08 mg g−1, which is remarkably superior to several previously reported adsorbents for TC removal. The TiO2@NC adsorbent performs efficiently in a broad pH range (3–8) and shows excellent stability. The post-adsorption characterization signifies the crucial role of the adsorbent's nitrogen sites, surface area, and porous sphere morphology in achieving efficient TC removal through hydrogen bonding, π-π interactions, and surface complexation.