Abstract
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•Synthesis and characterization of γ-cyclodextrin-graphene oxide nano-composite.•Economic and eco-friendly separation of tetracycline and chlortetracycline in water.•Super molecular mechanism of tetracycline and chlortetracycline adsorption by modeling.•Method work at natural water pHs (7.0–10.0) with low contact time.•May be used to remove tetracycline and chlortetracycline residue in any water body.
γ-Cyclodextrin-graphene oxide nanocomposite was synthesized and characterized for sorption, kinetics, thermodynamics, and simulation studies of tetracycline and chlortetracycline antibiotics removal from water. The optimized sorption parameters were 400 mg/L concentration, 30 min contact time, pH 8.0, dose 1.0 g/L and 25 °C temperature. The sorption followed Langmuir, Temkin, and D-Rs models. The maximum removals of tetracycline and chlortetracycline were 91.25 and 93.75% respectively, with a variation of percentage removal at different pHs ranges [355.0 (88.75%), 360.0 (90.0%) and 365.0 mg/g (91.25%) for tetracycline and 365.0 (91.25%), 370.0 (92.5%) and 375.0 mg/g (93.75%) chlortetracycline]. The sorption followed pseudo-second kinetic order reaction and liquid film diffusion kinetic model. The positive values of entropy (12.043 & 12.842 kJ/mol.K) and negative values of enthalpy (-0.944 & −1.113 kJ/mol) and free energy (-14.60 to −13.55 kJ/mol) confirmed the spontaneous sorption at all temperatures. The simulation results agreed with the sorption results. Also, the modeling was used to ascertain the supramolecular mechanism, which involved hydrogen bonding and π-π interactions.