Removal of minocycline and terramycin by graphene oxide and Cr/Mn base metal–organic framework composites

The graphene oxide and Cr/Mn base metal–organic framework (GO/Cr/Mn-MOF) composites were prepared by incorporating chromium acetate, tetrahydrate manganese acetate, and metal ions, using phthalic acid as the organic ligand. Before evaluating their efficacy in removing antibiotics, these GO/Cr/Mn-MOF composites were characterized using Fourier-transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy techniques. The experimental findings demonstrated that when 100 mg of GO/Cr/Mn-MOF composites were applied to a 30 mg·L −1 minocycline solution, the removal efficiencies for terramycin and minocycline reached 71% and 98.5%, respectively. In addition, upon adding 30 mg of GO/Cr/Mn-MOF composites to a 50 mg·L −1 terramycin solution, the highest adsorption capacity recorded within 5 h was 130.9 mg·g −1 . Likewise, introducing 20 mg of GO/Cr/Mn-MOF composites into a 50 mg·L −1 minocycline solution resulted in a maximum adsorption capacity of 236.6 mg·g −1 over the same duration. The experimental results were evaluated using both the Langmuir and Freundlich isothermal models, as well as kinetic models for analysis. The results show that the experimental data aligned with theoretical models, indicating that the removal process adhered to both second-order kinetics and multilayer adsorption mechanisms. Overall, the study concluded that physical adsorption was the primary mechanism governing the uptake of terramycin and minocycline by the GO/Cr/Mn-MOF composites.