title: Transmetallation of Gd-DTPA by Fe3+, Cu2+ and Zn2+ in water: batch experiments and coagulation-flocculation simulations.
abstract: The study investigates the stability of gadolinium-DTPA complex in presence of competing metallic ions, Fe(3+), Cu(2+) and Zn(2+) using batch experiments and coagulation-flocculation simulations. High performance liquid chromatography with fluorescence detection was used for simultaneous analysis of chelate gadolinium (Gd-DTPA) and free Gd(III) ion in water. It was shown that Cu(2+) has a strong affinity for DTPA and could lead to a complete release of Gd(3+). Fe(3+) appeared also to compete strongly with Gd(3+) for DTPA binding since up to 80% of Gd-complex was dissociated under iron excess condition. Finally, zinc had a lower influence on Gd speciation: only 15% of Gd(3+) was released with addition of a 5-fold excess of Zn(2+). During coagulation-flocculation simulation, Fe(3+) was able to displace about 27% of Gd-DTPA, and no adsorption was observed onto flocs.
authors.affiliation: Groupement de Recherche Eau Sol Environnement (GRESE), Université de Limoges, 123 avenue Albert Thomas, 87060 Limoges, France. Electronic address: marion.rabiet@unilim.fr.
authors.forename: Marion
authors.initials: M
authors.lastname: Rabiet
authors.forename: Marine
authors.initials: M
authors.lastname: Letouzet
authors.forename: Sepideh
authors.initials: S
authors.lastname: Hassanzadeh
authors.forename: Stéphane
authors.initials: S
authors.lastname: Simon
mesh_terms: D003287:Contrast Media / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D052918:Environmental Restoration and Remediation; D005427:Flocculation; D019786:Gadolinium DTPA / Q000737:chemistry*; D007477:Ions; D007501:Iron / Q000737:chemistry*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008956:Models, Chemical; D014867:Water; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods; D015032:Zinc / Q000737:chemistry*
chemical_list: D003287:Contrast Media; D007477:Ions; D014874:Water Pollutants, Chemical; D014867:Water; D003300:Copper; D007501:Iron; D015032:Zinc; D019786:Gadolinium DTPA
keywords: Chelate gadolinium; Coagulation–flocculation; Compete ions; Transmetallation