Adsorption of fluoroquinolone by carbon nanotubes: a combined experimental and density functional theory study

There is growing concern regarding the widespread use of fluoroquinolones (FQs) and their presence in the aqueous environment due to the rapid antibiotic resistance. In this study, wet chemistry experiment and DFT calculation were employed to investigate the adsorption of enrofloxacin (ENR), the most frequently used veterinary FQs, by carbon nanotubes (CNTs). The result revealed that the surface oxidation of CNT greatly modified its surface chemistry and thus had significant effect on ENR adsorption by the electrostatic and H-donor-acceptor interaction. Furthermore, the coexisted cations in environment could both react with ENR to form cation-dipole complex and react with CNT via cation-pi interaction, leading to an enhanced adsorption of ENR. These results highlight the important role of surface chemistry in the efficient removal of antibiotics in waters.