Identificador persistente para citar o vincular este elemento: http://hdl.handle.net/10553/45426
Título: Effect of Dunaliella tertiolecta organic exudates on the Fe(II) oxidation kinetics in seawater
Autores/as: González, A. G. 
Santana-Casiano, J. M. 
González-Dávila, M. 
Pérez-Almeida, N. 
Suárez De Tangil, M. 
Clasificación UNESCO: 2510 Oceanografía
251002 Oceanografía química
Palabras clave: Dunaliella tertiolecta
Oxidation
Seawater
Fecha de publicación: 2014
Proyectos: Estudio Del Comportamiento Químico Del Hierro en El Medio Marino en Presencia de Compuestos Orgánicos de Origen Fitoplanctónico 
Publicación seriada: Environmental science & technology 
Resumen: The role played by the natural organic ligands excreted by the green algae Dunaliella tertiolecta on the Fe(II) oxidation rate constants was studied at different stages of growth. The concentration of dissolved organic carbon increased from 2.1 to 7.1 mg L(-1) over time of culture. The oxidation kinetics of Fe(II) was studied at nanomolar levels and under different physicochemical conditions of pH (7.2-8.2), temperature (5-35 °C), salinity (10-37), and dissolved organic carbon produced by cells (2.1-7.1 mg L(-1)). The experimental rate always decreased in the presence of organic exudates with respect to that in the control seawater. The Fe(II) oxidation rate constant was also studied in the context of Marcus theory, where ΔG° was 39.31-51.48 kJ mol(-1). A kinetic modeling approach was applied for computing the equilibrium and rate constants for Fe(II) and exudates present in solution, the Fe(II) speciation, and the contribution of each Fe(II) species to the overall oxidation rate constant. The best fit model took into account two acidity equilibrium constants for the Fe(II) complexing ligands with pKa,1=9.45 and pKa,2=4.9. The Fe(II) complexing constants were KFe(II)-LH=3×10(10) and KFe(II)-L=10(7), and the corresponding computed oxidation rates were 68±2 and 36±8 M(-1) min(-1), respectively.
URI: http://hdl.handle.net/10553/45426
ISSN: 0013-936X
DOI: 10.1021/es5013092
Fuente: Environmental Science and Technology [ISSN 0013-936X], v. 48 (14), p. 7933-7941
Colección:Artículos
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