Synergistic effect of Cu-nanoparticles and β-cyclodextrin functionalized reduced graphene oxide nanocomposite on the adsorptive remediation of tetracycline antibiotics

Pollution by tetracyclines antibiotics has a great potential risk on human and animal health even at trace levels. Copper nanoparticles immobilized-β-cyclodextrin functionalized reduced graphene oxide (Cu/β-CD/rGO) were successfully prepared as an efficient extractor of tetracycline (TC), oxytetracycline (OTC) and doxycycline (DC) antibiotics from different environmental water samples. Tetracyclines (TCs) are strongly deposited in the matrix of Cu/β-CD/rGO nanocomposite via surface complexation with the Cu-nanoparticles besides the formation of inclusion complexes with β-cyclodextrin and π-π interaction of reduced graphene oxide. The novel nanocomposite was characterized by HRSEM, TEM, TGA, FT-IR, XPS, and XRD. The optimization of variables such as the pH, contact time, ionic strength and TC concentration were successfully analyzed. The maximum adsorption capacity (qm) of Cu/β-CD/rGO calculated from the Langmuir isotherm was 403.2 mg.g-1 for TC, 476.2 mg.g-1 for OTC and 434.8 mg.g-1 for DC at 298 K. The removal efficiency was decreased by 3.7% after five adsorption-desorption cycles. The Cu/β-CD/rGO nanocomposite was applied for removing TCs from tap water and the Nile River water samples. The novel nanocomposite demonstrated fast and highly efficient removing performance for different TCs with low levels and large sample volume.