Modeling of the Adsorption of Tigecycline from Water on CoFe₂O₄-Graphene Nanocomposites

A CoFe₂O₄(11.04%)-graphene (5.45%) nanocomposite was synthesized and characterized by spectroscopic techniques. This nanocomposite was used to eliminate tigecycline antibiotics from the water. The adsorbent showed 160.0 mg/g adsorption capacity of tigecycline antibiotic at 175 mg/L tigecycline, 0.75 g/L dose, 100 min of contact time, and a temperature of 25 °C. One-, two-, and three-parameter models were applied, i.e., Henry, Langmuir, Freundlich, D-R, Temkin, Flory-Huggins, Halsey, Jovanovich, Redlich-Peterson, and Sips models. According to statistical data, Langmuir and Sips models were the best fitted. The adsorption was spontaneous thermodynamically following pseudo-second-order kinetics. The adsorption occurred via a combination of intraparticle diffusion and external mass transfer mechanisms. The supramolecular mechanism showed the adsorption of the tigecycline antibiotic via coordination and π-π stacking bonds. The characterization results showed that the average nanoparticle size obtained was 91.45 nm. The removal efficiency of the adsorbent reduced up to the fifth cycle and later became constant at 50%. Hence, CoFe₂O₄-graphene nanocomposites propose a highly effective and recyclable solution for water treatment through adsorption, and hence, this method may be used to remove tigecycline antibiotics from water bodies.