Journal
CHEMOSPHERE
Volume 95, Issue -, Pages 150-155Publisher
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.chemosphere.2013.08.053
Keywords
Antibiotics; Nanotubes; Hydrophobicity; Desorption hysteresis; Sorption energy
Categories
Funding
- National Basic Research Program of China [2011CB100506-01, 2010CB134509]
- BARD [IS-4353-10]
- USDA-AFRI Hatch program [MAS 00978]
- China Scholarship Council
Ask authors/readers for more resources
The environmental risks of antibiotics have attracted increasing research attention, but their environmental behaviors remain unclear. In this study, functionalized carbon nanotubes (CNTs), namely, hydroxylized (MH), carboxylized (MC), graphitized multi-walled CNTs (MG) and single-walled CNTs (SW) were used as adsorbents and ciprofloxacin (CIP) as an adsorbate to investigate the effect of pH and temperature on sorption and desorption processes. Sorption isotherms of CIP were fitted well by Freundlich and Dubinin-Ashtakhov models. Highly nonlinear isotherms of CIP were observed, indicating the highly heterogeneous site energy distribution on CNTs. At all pHs, SW had the highest sorption for CIP due to its largest surface area among all CNTs. Sorption distinction between MH and MC was explained by pi-pi electron donor-acceptor interactions. For SW, CIP sorption was thermodynamically favorable and endothermic associated with an entropy driven process, while the reverse process occurred for MC and MG. The rearrangement of CNTs bundles/aggregates and covalent bond formation may be responsible for CIP desorption hysteresis on CNTs. Desorption of antibiotics from CNTs may lead to potential exposure, particularly under changing environmental conditions such as temperature and pH. (C) 2013 Elsevier Ltd. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available