Sorption of sulfate ions onto magnetite

Mansour, C.; Lefèvre, Grégory; Pavageau, E.M.; Catalette, H.; Fédoroff, M.; Zanna, Sandrine

doi:10.1016/j.jcis.2008.11.009

Cited by 33 publications

(16 citation statements)

References 23 publications

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“…For example, ligand exchange mechanisms may predominate in neutral to acidic systems, whereas anion exchange predominates in alkaline soils. This is the case for arsenate, molybdate, and sulfate retention by Fe-and Aloxyhydroxides (Catalano et al, 2008;Goldberg, 2014aGoldberg, , 2014bMansour et al, 2009) and for selenite and selenate by gibbsite and phyllosilicates (Goldberg, 2014b(Goldberg, , 2014c.…”

Section: Resultsmentioning

confidence: 95%

Adsorption of Antimonate by Gibbsite: Reversibility and the Competitive Effects of Phosphate and Sulfate

Essington

Stewart

2016

Soil Science Soc of Amer J

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Antimony (sb) is a potential environmental contaminant of emerging concern that occurs in soils in the sb(V) oxidation state as the antimonate species sb(OH) 6 -. In soils, metal oxyhydroxides play an important role in the immobilization of contaminants and in restricting bioaccessibility. One such mineral is gibbsite, which bears the reactive aluminol surface functional group. Both inner-and outer-sphere surface complexation mechanisms have been inferred from conflicting sb(V) adsorption findings involving aluminol-bearing minerals. The objectives of this research are to characterize sb(V) adsorption by gibbsite and to use the macroscopic findings to develop mechanistic adsorption models. Antimonate adsorption envelopes were developed using two equilibrium techniques: continuous pH titration and batch. The adsorption of sb(V) decreases with increasing pH and increasing ionic strength, suggesting that outer-sphere surface complexation is an important adsorption mechanism. However, sb(V) retention is irreversible at pH <6 but is reversible in pH >7 systems, suggesting that inner-sphere species may be significant in acidic environments. Adsorbed sb(V) also generates a downward shift in the gibbsite isoelectric point, further supporting the formation of inner-sphere sb(V) surface complexes. Both PO 4 and sO 4 decrease adsorbed sb(V) concentrations: PO 4 throughout the pH 3 to 10 range and sO 4 in pH <7 systems. The triple-layer surface complexation model successfully predicts sb(V) adsorption by using both outer-sphere and inner-sphere surface species. The triple-layer model also predicts ligand adsorption in the competitive systems without the need for reoptimization.Abbreviations: BET, Brunauer-Emmett-Teller; ICP-AES, inductively coupled argon plasma-atomic emission spectroscopy; IEP, isoelectric point; SCM, surface complexation model; TLM, triple layer model; XRD, x-ray diffraction.A ntimony is one of the least abundant elements in soils, having a median concentration in uncontaminated soils from around the world of 1 mg kg −1 (range, <0.2-10 mg kg −1 ) (Bowen, 1979;Filella et al., 2002;Helmke, 2000). However, anthropogenic activities can result in elevated soil Sb levels (Crecelius et al., 1975;Filella et al., 2002;Li and Thornton, 1993;Nriagu, 1989;Nriagu and Pacyna, 1988;Scheinost et al., 2006). Soils that are particularly affected by Sb are those at military and civilian shooting ranges. Antimony is a hardening agent in lead bullets, which contain ~5% Sb (Carlin, 2000;Johnson et al., 2005;Kilgour et al., 2008). As bullets and bullet fragments corrode, Pb and Sb are released to the soil environment (Clausen and Korte, 2009;Kilgour et al., 2008). The resulting Sb concentrations can far exceed native soil levels. Antimony concentrations in military and civilian shooting range soils have been reported to range from <517 to <17,500 mg kg −1 (Basunia and Landsberger, 2001;Johnson et al., 2005;Kilgour et al., 2008;Knechtenhofer et al., 2003;Mitsunobu et al., 2006;Okkenhaug et al., 2013;Spuller et al., 2007), alth...

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Section: Resultsmentioning

confidence: 95%

Adsorption of Antimonate by Gibbsite: Reversibility and the Competitive Effects of Phosphate and Sulfate

Essington

Stewart

2016

Soil Science Soc of Amer J

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“…Determination of the isoelectrical point (pH iep ) yielded values for fmag and pomag of pH 5.5 and pH 6, respectively. Literature values for commercial, synthesized and natural magnetite range between pH $4 and $8 (Kosmulski, 2001;Illes and Tombacz, 2006;Mansour et al, 2009). …”

Section: Solid Phase Characterizationmentioning

confidence: 99%

U(VI) removal kinetics in presence of synthetic magnetite nanoparticles

Huber

Schild

Vitova

et al. 2012

Geochimica et Cosmochimica Acta

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“…A magnetic sorbent was developed for the removal of copper ions from water by Lim et al [20]. Mansour et al examined the sorption of sulfate ions onto magnetite [21]. These studies demonstrate that sorption by magnetic sorbent is a promising and potential alternative for the decontamination of polluted water.…”

Section: Introductionmentioning

confidence: 99%