Hierarchically porous UiO-67-bpy metal-organic gels for efficient tetracycline removal

The existence of TC residues in the environment and the resultant development of opposition mechanisms constitute a serious menace to both ecological systems and human health. In the present study, UiO-67-bpy-X gels were prepared by the introduction of H₂bpydc ligands and acetic acid modifiers, followed by a systematic evaluation of their TC adsorption capabilities. Characterization results revealed that UiO-67-bpy-2.4 gel displayed raised specific surface area (1953 m² g^-1) and a graded porous structure. When conditions were optimized, the material manifested a maximum TC adsorptive capacity of 404.1 mg g^-1, outperforming the performance of most reported adsorbents. The kinetic modeling and adsorption isotherm analyses implied that chemical adsorption constituted the dominant uptake pathway. The adsorptive mechanism was further analyzed by XPS, FT-IR, and DFT calculations, which can be attributed to the synergistic effects of metal coordination, electronic interaction, hydrogen bonding, and π-π interaction. Furthermore, the material exhibited good structural stability, retaining 85.945 % of its original adsorptive capacity after six cycles. These findings suggested that UiO-67-bpy-2.4 gel held significant promise as environmental remediation materials, offering high adsorptive capacity and ease of recycling, thereby presenting a novel approach to addressing TC contamination.