Effect of citrate on the local Fe coordination in ferrihydrite, arsenate binding, and ternary arsenate complex formation

Mikutta, Christian; Frommer, Jakob; Voegelin, Andreas; Kaegi, Rälf; Kretzschmar, Ruben

doi:10.1016/j.gca.2010.06.024

Cited by 87 publications

(84 citation statements)

References 73 publications

(116 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, the differences in valence and initial concentration of As in laboratory and field experiments can contribute to the lower ARE values of field treatment. In addition, the presence of 2.8e5.5 mg L À1 DOC in the field electrolytes, which was absent in the laboratory experiments, can also contribute to the lower ARE values of field experiments by competing with As for sorption sites on the Fe(III) precipitate surface (Mikutta et al, 2010). The presence of DOC can also lead to Fe(III) precipitates with strong negative surface charge, which would decrease As(V) removal and potentially result in to colloidally stable suspensions that are difficult to remove from treated water (Wan et al, 2011).…”

Section: Fe(iii) Polymerization and As Sorptionmentioning

confidence: 97%

Formation of macroscopic surface layers on Fe(0) electrocoagulation electrodes during an extended field trial of arsenic treatment

et al. 2016

View full text Add to dashboard Cite

Section: Fe(iii) Polymerization and As Sorptionmentioning

confidence: 97%

Formation of macroscopic surface layers on Fe(0) electrocoagulation electrodes during an extended field trial of arsenic treatment

et al. 2016

View full text Add to dashboard Cite

“…All spectra for each sample were fitted using a single starting structural model consisting of As-O and As-Al single scattering paths and three multiple scattering paths: a triangular As-O-O path, a collinear As-O-As-O path, and a non-collinear As-O-As-O path. The parameters for these paths were determined from geometric considerations [31]. In the model fits, As-O coordination numbers were fixed at 4 and the coordination numbers of As-Al shells were allowed to vary.…”

Section: Exafs Spectroscopic Measurementsmentioning

confidence: 99%

Effects of Ionic Strength on Arsenate Adsorption at Aluminum Hydroxide–Water Interfaces

Catalano

2018

Soil Systems

View full text Add to dashboard Cite

Adsorption processes at mineral-water interfaces control the fate and transport of arsenic in soils and aquatic systems. Mechanistic and thermodynamic models to describe this phenomenon only consider inner-sphere complexes but recent observation of the simultaneous adsorption of inner-and outer-sphere arsenate on single crystal surfaces complicates this picture. In this study, we investigate the ionic strength-dependence of the macroscopic adsorption behavior and molecular-scale surface speciation of arsenate bound to gibbsite and bayerite. Arsenate adsorption decreases with increasing ionic strength on both minerals, with a larger effect at pH 4 than pH 7. The observed pH-dependence corresponds with a substantial decrease in surface charge at pH 7, as indicated by ζ-potential measurements. Extended X-ray absorption fine structure (EXAFS) spectroscopy finds that the number of second shell Al neighbors around arsenate is lower than that required for arsenate to occur solely as an inner-sphere surface complex. Together, these observations demonstrate that arsenate displays macroscopic and molecular-scale behavior consistent with the co-occurrence of inner-and outer-sphere surface complexes. This demonstrated that outer-sphere species can be responsible for strong adsorption of ions and suggests that environments experiencing an increase in salt content may induce arsenic release to water, especially under weakly acidic conditions.

show abstract

“…Colloids are particles or aggregates with diameters between 1 nm and 1 µm (IUPAC, 1997). Electrostatic stabilization caused by adsorbed citrate stabilizes colloidal suspensions against aggregation (Mikutta et al, 2010) and helps to form small particles from larger aggregates (Stumm and Furrer, 1987). The stability of a colloidal suspension in turn has a strong impact on the reactivity of Fe hydroxides caused by the higher specific surface area compared to large aggregates.…”

Section: Introductionmentioning

confidence: 99%

Citrate influences microbial Fe hydroxide reduction via a dissolution–disaggregation mechanism

Braunschweig

Klier

Schröder

et al. 2014

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

Please cite this article as: Braunschweig, J., Klier, C., Schröder, C., Händel, M., Bosch, J., Totsche, K.U., Meckenstock, R.U., Citrate influences microbial Fe hydroxide reduction via a dissolution-disaggregation mechanism, Geochimica et Cosmochimica Acta (2014), doi: http://dx.doi.org/10.1016/j.gca. 2014.05.006 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Modelling of abiotic dissolution kinetics revealed that colloid stabilization was most pronounced at citrate:Fe ratios of 0.1 -0.5, whereas higher ratios led to enhanced dissolution of both colloidal and larger aggregated fractions. Mathematical simulation of the microbial reduction kinetics under consideration of partial dissolution and colloid stabilization showed that the bioaccessibility increases in the order large aggregates < stable colloids < Fe-citrate.These findings indicate that much of the organic acid driven mobilization of Fe oxy(hydr)oxides is most likely due to colloid formation and stabilization rather than solubilisation.

show abstract

Effect of citrate on the local Fe coordination in ferrihydrite, arsenate binding, and ternary arsenate complex formation

Cited by 87 publications

References 73 publications

Formation of macroscopic surface layers on Fe(0) electrocoagulation electrodes during an extended field trial of arsenic treatment

Formation of macroscopic surface layers on Fe(0) electrocoagulation electrodes during an extended field trial of arsenic treatment

Effects of Ionic Strength on Arsenate Adsorption at Aluminum Hydroxide–Water Interfaces

Citrate influences microbial Fe hydroxide reduction via a dissolution–disaggregation mechanism

Contact Info

Product

Resources

About