Defect-regulated and amino-functionalized UiO-67 for efficient removal of tetracycline hydrochloride from aqueous solutions

There is notable interest in the development of the efficient removal technologies for antibiotic contaminants in aqueous environments. In this study, L-cysteine was introduced into a UiO-67 precursor solution, and the defective amino-functionalized adsorbent UiO-67-HAc-NH2 was synthesized via a hydrothermal method. This adsorbent was used for the adsorption of tetracycline hydrochloride (TCH) from aqueous solutions. The characterization results confirmed the successful incorporation of amino groups into the adsorbent through L-cysteine and indicated that the defective structure, resulting from competitive interactions with organic ligands, significantly increased the specific surface area. UiO-67-HAc-NH2 demonstrated a maximum adsorption capacity of 605 mg/g for TCH and a notable enhancement in the specific surface area from 704.1 m2/g for pristine UiO67-2858.7 m2/g. The adsorption mechanism was governed by the synergistic interplay of coordination, acidbase interactions, pi-pi conjugation, and weak noncovalent interactions. Recycling and regeneration experiments indicated that UiO-67-HAc-NH2 retained a regeneration recovery rate exceeding 90 %, highlighting its excellent reusability as an adsorbent. This result indicates the significant potential of defective aminofunctionalized metal-organic framework (MOFs) materials for antibiotic adsorption applications.