title: Removal of gadolinium-based contrast agents: adsorption on activated carbon.
abstract: Three carbon samples were employed in this work, including commercial (1690 m2g-1), activated carbon prepared from guava seeds (637 m2g-1), and activated carbon prepared from avocado kernel (1068 m2g-1), to study the adsorption of the following gadolinium-based contrast agents (GBCAs): gadoterate meglumine Dotarem®, gadopentetate dimeglumine Magnevist®, and gadoxetate disodium Primovist®. The activation conditions with H3PO4were optimized using a Taguchi methodology to obtain mesoporous materials. The best removal efficiency by square meter in a batch system in aqueous solution and model urine was achieved by avocado kernel carbon, in which mesoporosity prevails over microporosity. The kinetic adsorption curves were described by a pseudo-second-order equation, and the adsorption isotherms in the concentration range 0.5-6 mM fit the Freundlich equation. The chemical characterization of the surfaces shows that materials with a greater amount of phenolic functional groups adsorb the GBCA better. Adsorption strongly depends on the pH due to the combination of the following factors: contrast agent protonated forms and carbon surface charge. The tested carbon samples were able to adsorb 70-90% of GBCA in aqueous solution and less in model urine. This research proposes a method for the elimination of GBCA from patient urine before its discharge into wastewater.
authors.affiliation: Centro de Química, Instituto de Ciencias, Universidad Autónoma de Puebla, Ciudad Universitaria, Av. San Claudio s/n. Edif. 103H, 72570, Puebla, Pue, Mexico.
authors.forename: María P
authors.initials: MP
authors.lastname: Elizalde-González
authors.affiliation: Centro de Química, Instituto de Ciencias, Universidad Autónoma de Puebla, Ciudad Universitaria, Av. San Claudio s/n. Edif. 103H, 72570, Puebla, Pue, Mexico. esmeralda.garcia.uap@gmail.com.
authors.forename: Esmeralda
authors.initials: E
authors.lastname: García-Díaz
authors.affiliation: Facultad de Ciencias Químicas, Universidad Autónoma de Puebla, Ciudad Universitaria, Edif. 105I, 72570, Puebla, Pue, Mexico.
authors.forename: Mario
authors.initials: M
authors.lastname: González-Perea
authors.affiliation: Department Analytical Chemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318, Leipzig, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Mattusch
mesh_terms: D000327:Adsorption; D002244:Carbon / Q000737:chemistry*; D003287:Contrast Media / Q000737:chemistry*; D019786:Gadolinium DTPA / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008536:Meglumine / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D014556:Urine / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D014876:Water Pollution / Q000517:prevention & control
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; D014874:Water Pollutants, Chemical; C073590:gadolinium ethoxybenzyl DTPA; D008536:Meglumine; D002244:Carbon; D019786:Gadolinium DTPA; C072417:gadoterate meglumine
keywords: Activated carbon; Adsorption; Emerging water pollutants; Gadolinium-based contrast agents; Model urine