title: Adsorption of ofloxacin and norfloxacin on carbon nanotubes: hydrophobicity- and structure-controlled process.
abstract: Adsorption of antibiotics on solid particles is a key process controlling their fate in the subsurface. This study compared the adsorption of ofloxacin and norfloxacin (NOR) on carbon nanotubes (CNTs) to evaluate the role of structural and hydrophobic properties in regulating their adsorption. A significant relationship was observed between single-point adsorption coefficients (K(d)) and specific surface area (highly hydrophobic), but not between K(d)s and oxygen content. This result suggested that site-specific adsorption was not important but hydrophobic effect may have an important contribution to OFL and NOR adsorption on CNTs. However, normalizing the adsorption coefficients by OFL and NOR solubilities enlarged their adsorption difference indicating that hydrophobicity was not the only factor controlling the difference between OFL and NOR adsorption on CNTs. Their chemical structures show that both chemicals could interact with CNTs through an electron-donor-acceptor mechanism. This mechanism was correlated with the different adsorption of OFL and NOR on functionalized CNTs (namely hydroxylized, carboxylized, and graphitized CNTs). This study revealed that OFL and NOR adsorption was controlled by their both structural- and hydrophobic-properties.
authors: Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming, Yunnan 650093, China.
authors: Hongbo
authors: H
authors: Peng
authors: Bo
authors: B
authors: Pan
authors: Min
authors: M
authors: Wu
authors: Ying
authors: Y
authors: Liu
authors: Di
authors: D
authors: Zhang
authors: Baoshan
authors: B
authors: Xing
mesh_terms: D000327:Adsorption; D000900:Anti-Bacterial Agents / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D015394:Molecular Structure; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009643:Norfloxacin / Q000737:chemistry*; D015242:Ofloxacin / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry; D018508:Water Purification / Q000379:methods
chemical_list: D000900:Anti-Bacterial Agents; D037742:Nanotubes, Carbon; D014874:Water Pollutants, Chemical; D015242:Ofloxacin; D009643:Norfloxacin