title: Oxolinic Acid Binding at Goethite and Akaganéite Surfaces: Experimental Study and Modeling.
abstract: Oxolinic acid (OA) is a widely used quinolone antibiotic in aquaculture. In this study, its interactions with synthetic goethite (α-FeOOH) and akaganéite (β-FeOOH) particle surfaces were monitored to understand the potential fate of OA in marine sediments where these phases occur. Batch sorption experiments, liquid chromatography (LC) analyses of supernatants, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy and multisite complexation (MUSIC) modeling were used to monitor OA binding at these particle surfaces. Both LC and ATR-FTIR showed that adsorption did not degrade OA, and that OA adsorption was largely unaffected by NaCl concentrations (10-1000 mM). This was explained further by ATR-FTIR suggesting the formation of metal-bonded complexes at circumneutral to low pHc = -log [H(+)] and with a strongly hydrogen-bonded complex at high pHc. The stronger OA binding to akaganéite can be explained both by the higher isoelectric point/point-of-zero charge (9.6-10) of this mineral than of goethite (9.1-9.4), and an additional OA surface complexation mechanism at the (010) plane. Geminal sites (≡Fe(OH2)2(+)) at this plane could be especially reactive for metal-bonded complexes, as they facilitate a mononuclear six-membered chelate complex via the displacement of two hydroxo/aquo groups at the equatorial plane of a single Fe octahedron. Collectively, these findings revealed that Fe-oxyhydroxides may strongly contribute to the fate and transport of OA-type antibacterial agents in marine sediments and waters.
authors.affiliation: Ecole Nationale Supérieure de Chimie de Rennes, UMR CNRS 6226 , 11 Allée de Beaulieu, F-35708 Rennes Cedex 7, France.
authors.forename: Rémi
authors.initials: R
authors.lastname: Marsac
authors.affiliation: Ecole Nationale Supérieure de Chimie de Rennes, UMR CNRS 6226 , 11 Allée de Beaulieu, F-35708 Rennes Cedex 7, France.|Department of Chemistry, Umeå University , Umeå, SE-901 87, Sweden.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Martin
authors.affiliation: Department of Chemistry, Umeå University , Umeå, SE-901 87, Sweden.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Boily
authors.affiliation: Ecole Nationale Supérieure de Chimie de Rennes, UMR CNRS 6226 , 11 Allée de Beaulieu, F-35708 Rennes Cedex 7, France.
authors.forename: Khalil
authors.initials: K
authors.lastname: Hanna
mesh_terms: D000327:Adsorption; D000900:Anti-Bacterial Agents / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D019015:Geologic Sediments / Q000032:analysis*; D058085:Iron Compounds / Q000737:chemistry*; D008903:Minerals / Q000737:chemistry*; D008956:Models, Chemical; D010093:Oxolinic Acid / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D005290:Ferric Compounds; D058085:Iron Compounds; D008903:Minerals; D014874:Water Pollutants, Chemical; C473845:akaganeite; C094886:goethite; D010093:Oxolinic Acid