Adsorption Properties of Doxycycline Antibiotic from Aqueous Solutions Onto Pristine, Activated and Magnetized Carbon Nanotubes

The presence of antibiotics in aquatic environments has been recognized as an issue warranting consideration. Increasing concerns have been raised regarding the potential risks of antibiotics to human and ecological health due to their extensive use. More efficient and cost-effective adsorbents are urgently needed and are the focus of intense research effort. Previous studies have demonstrated that carbon nanotubes can be used as effective adsorbent materials to remove organic contaminants [2].

In this study, magnetic multi-walled carbon nanotubes (MMWNTs) were synthesized from iron salt solution [3]. Pristine, oxidized and magnetized MWNTs were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). The three solid samples were then investigated for the adsorption of doxycycline antibiotic (DOX) from aqueous solutions. The influence of adsorbent mass, contact time, the temperature and the pH on the adsorption of DOX on the three types of solids was investigated by conducting a series of batch adsorption experiments. The equilibrium data at different temperatures were fitted with the Langmuir, Freundlich, Tempkin, Redlich-Peterson models. Adsorption results showed that the maximum percentage removal of DOX from aqueous solution by pristine, oxidized and magnetized MWCNTâ??s were 99.39%, 78.79% and 94.68% respectively.

Our results indicate that surface properties and aqueous solution chemistry play important roles in DOX adsorption on MWCNTs.

Key words: adsorption, pristine multi-walled carbon nanotubes, oxidized multi-walled carbon nanotubes, magnetized multi-walled carbon nanotubes, water treatment, antibiotics, doxycycline, multi-walled carbon nanotubes, nanotechnology.

References

[1] Mauter, M.S.; Elimelech, M. Environmental applications of carbon-based nanomaterials. Environ. Sci. Technol. 2008, 42, 5843â??5859.

[2] Liangliang Ji et al., Adsorption of tetracycline on single-walled and multi-walled carbon nanotubes as affected by aqueous solution chemistry. Environmental Toxicology and Chemistry. 2010, 19 : 2713-2719

[3] Fazelirad H, Ranjbar M, Taher M, Sargazi Gh Preparation of magnetic multi-walled carbon nanotubes for an efficient adsorption and spectrophotometric determination of amoxicillin. Journal of Industrial and Engineering Chemistry. 2015, 21: 889â??892.

Acknowledgements

This work was supported by the Research Grant of Nazarbayev University.