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Personen: Xiaochen, Li (Autor) 
Reich, Tatiana (Autor) 
Kersten, Michael (Autor) 
Jing, Chuanyong (Autor) 
Titel: Low-molecular-weight organic acid complexation affects antimony(III) adsorption by granular ferric hydroxide
Quelle: Environmental science & technology. Bd. 53. H. 9. Columbus, Ohio : American Chemical Society. S. 5221 - 5229
Erscheinungsjahr:    2019
ISBN / ISSN: 1520-5851 ; 0013-936X
URL der Originalveröffentlichung doi:10.1021/acs.est.8b06297
Zeitschriftenaufsatz Zeitschriftenaufsatz
Sprache: Englisch
Open Access:
Person der Universität:    Kersten, Michael  In UnivIS suchen 
Einrichtung: Institut für Geowissenschaften
DDC-Sachgruppe:    Geowissenschaften
DFG-Fachgebiet: Wasserforschung
ID: 59060  Universitätsbibliothek Mainz
Informationen zu den Nutzungsrechten unserer Inhalte Informationen zu den Nutzungsrechten unserer Inhalte
Abstract: Antimony(III) mobility in natural aquatic environments is generally enhanced by dissolved organic matter. Tartaric acid is often used to form complexes with and stabilize dissolved Sb(III) in adsorption studies. However, competition between such low-molecular-weight organic acid complexation and adsorption of Sb(III) has received little attention, which prompted us to measure Sb(III) adsorption by iron oxyhydroxide adsorbents commonly used in water treatment plants. Sb K-edge X-ray absorption fine structure (EXAFS) spectra gave Sb−O and Sb−Fe distances and coordinations compatible with a bidentate binuclear innersphere complex with trigonal Sb(O,OH)3 polyhedra sharing corners with Fe(O,OH)6 octahedra and a bidentate mononuclear inner-sphere complex but with Sb(O,OH)4 tetrahedra at alkaline pH. Experimental batch titration data were fitted using the charge-distribution multisite surface complexation (CD-MUSIC) model, constrained by the EXAFS molecular level information and taking competitive effects by the organic ligand into consideration. The proportion adsorbed at acid to neutral pH decreased as the Sb(III) concentration increased. The CD-MUSIC adsorption model indicates that this was solely caused by strong competition from tartrate complexation in solution, which leads to adsorption constants higher than those derived without taking this competition into account. The adsorption model results allow for calculating a pe−pH predominance diagram using the USGS PhreePlot code. The study provides consistent surface complexation stability constants, allowing the new database to be used also to reliably model adsorption of toxic oxyanions in anoxic aqueous environments: for example, to accurately simulate competition between Sb(III) and As(III).
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