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dc.creatorMéndez Fernández, Juan Carlos
dc.creatorHiemstra, Tjisse
dc.date.accessioned2021-06-24T15:30:27Z
dc.date.available2021-06-24T15:30:27Z
dc.date.issued2018-12
dc.identifier.citationhttps://pubs.acs.org/doi/10.1021/acsearthspacechem.8b00160es_ES
dc.identifier.issn2472-3452
dc.identifier.urihttps://hdl.handle.net/10669/83781
dc.description.abstractCarbonate (CO3) interacts with Fe-(hydr)oxide nanoparticles, affecting the availability and geochemical cycle of other important oxyanions in nature. Here, we studied the carbonate–phosphate interaction in closed systems with freshly prepared ferrihydrite (Fh), using batch experiments that cover a wide range of pH values, ionic strength, and CO3 and PO4 concentrations. The surface speciation of CO3 has been assessed by interpreting the ion competition with the Charge Distribution (CD) model, using CD coefficients derived from MO/DTF optimized geometries. Adsorption of CO3 occurs predominately via formation of bidentate inner-sphere complexes, either (≡FeO)2CO or (≡FeO)2CO··Na+. The latter complex is electrostatically promoted at high pH and in the presence of adsorbed PO4. Additionally, a minor complex is present at high CO3 loadings. The CD model, solely parametrized by measuring the pH-dependent PO4 adsorption as a function of the CO3 concentration, successfully predicts the CO3 adsorption to Fh in single-ion systems. The adsorption affinity of CO3 to Fh is higher than to goethite, particularly at high pH and CO3 loadings due to the enhanced formation (≡FeO)2CO··Na+. The PO4 adsorption isotherm in 0.5 M NaHCO3 can be well described, being relevant for assessing the reactive surface area of the natural oxide fraction with soil extractions and CD modeling. Additionally, we have evaluated the enhanced Fh solubility due to Fe(III)-CO3 complex formation and resolved a new species (Fe(CO3)2(OH)23−(aq)), which is dominant in closed systems at high pH. The measured solubility of our Fh agrees with the size-dependent solubility predicted using the surface Gibbs free energy of Fh.es_ES
dc.description.sponsorshipUniversidad de Costa Rica/[]/UCR/Costa Ricaes_ES
dc.language.isoenges_ES
dc.sourceACS Earth and Space Chemistry, vol.3(1), pp.129-141es_ES
dc.subjectFerrihydritees_ES
dc.subjectGoethitees_ES
dc.subjectNanoparticleses_ES
dc.subjectIon adsorptiones_ES
dc.subjectSurface complexationes_ES
dc.subjectCompetitiones_ES
dc.subjectCD modeles_ES
dc.subjectSolubilityes_ES
dc.titleCarbonate adsorption to ferrihydrite: Competitive interaction with phosphate for use in soil systemses_ES
dc.typeartículo científicoes_ES
dc.identifier.doi10.1021/acsearthspacechem.8b00160
dc.description.procedenceUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Centro de Investigaciones Agronómicas (CIA)es_ES


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