Fe(II)–Na ion exchange at interlayers of smectite: adsorption–desorption experiments and a natural analogue

Kamei, Gento; Oda, Chie; Mitsui, S.; Shibata, Masahiro; Shinozaki, Tomohiro

doi:10.1016/s0013-7952(99)00057-5

Cited by 50 publications

(22 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has two reactive surfaces: the siloxane basal planes, and the edges 7 with mixed aluminol and silanol groups. Fe 2+ sorbs to these siloxane planes by cation exchange KAMEI et al, 1999). It also sorbs to the edges via a complex pH-dependent surface complexation mechanism (Géhin et al, 2007).…”

Section: The Reactive Fe(ii)-clay Systemmentioning

confidence: 99%

Electron transfer at the mineral/water interface: Selenium reduction by ferrous iron sorbed on clay

Charlet

Scheinost²,

Tournassat

et al. 2007

Geochimica et Cosmochimica Acta

183

129

View full text Add to dashboard Cite

Electron transfer at the mineral/water interface: Selenium reduction by ferrous iron sorbed on clay. Geochimica et Cosmochimica Acta, Elsevier, 2007, 71 (23) , selenite was sorbed as outer-sphere sorption complex, covering only part of the positive edge sites, as verified by a structure-based MUSIC model and Se K-edge XAS (X-ray absorption spectroscopy). When selenite was added to montmorillonite previously equilibrated with Fe 2+ solution however, slow reduction of Se and formation of a solid phase was observed with Se K-edge XANES (x-ray absorption near-edge spectroscopy) and EXAFS (extended x-ray absorption finestructure) spectroscopy. Iterative transformation factor analysis of XANES and EXAFS spectra suggested that only one Se reaction product formed, which was identified as nano-particulate Se(0). Even after one month, only 75% of the initially sorbed Se(IV) was reduced to this solid species. Mössbauer spectrometry revealed that before and after addition and reduction of Se, 5% of total sorbed Fe occurred as

show abstract

Section: The Reactive Fe(ii)-clay Systemmentioning

confidence: 99%

Electron transfer at the mineral/water interface: Selenium reduction by ferrous iron sorbed on clay

Charlet

Scheinost²,

Tournassat

et al. 2007

Geochimica et Cosmochimica Acta

183

129

View full text Add to dashboard Cite

show abstract

“…The most probable reaction would be the conversion of exchangeable cations of montmorillonite from Na þ to Fe 2þ ions (i.e., conversion of Namontmorillonite to Fe(II)-montmorillonite) since a deepunderground repository is under a reducing condition. 4,5) Carlson et al 6) reported higher hydraulic conductivity for altered bentonite samples that were obtained by contacting solution-saturated bentonite with carbon steel wire at 30 and 50 C for 829 and 911 d, respectively, and cast iron coupons at 30 and 50 C for 900 and 356 d, respectively. Although they suggested ion exchange reaction of Fe 2þ ions with Na þ ions in the montmorillonite interlayer, the extent of the reaction and its effects on the hydraulic conductivity had not been clarified in their study.…”

Section: Introductionmentioning

confidence: 99%

A Study on Hydraulic Properties of Compacted Fe(III)-montmorillonite

Ito¹,

Miyasaka

Kozaki

et al. 2010

Journal of Nuclear Science and Technology

View full text Add to dashboard Cite

Hydraulic conductivities were determined for compacted Fe(III)-montmorillonite sample. The Fe(III)-montmorillonite sample used in this study, which was prepared by the ion-exchange treatment of Namontmorillonite in FeCl 3 solution, contains less than 20% of Na þ ions as exchangeable cations and negligibly small amounts of iron precipitates. The measured hydraulic conductivities of compacted Fe(III)-montmorillonite were determined to be the order of 10 À9 , 10 À11 , and 10 À13 m s À1 at dry densities of 0.80, 1.01, and 1.20 Mg m À3 , respectively. These values were found to be kept constant during the experimental period, suggesting no significant change in the physicochemical properties of Fe(III)-montmorillonite during the experiment. When compared with Na-montmorillonite, remarkably high values of hydraulic conductivities were found for Fe(III)-montmorillonite at the dry densities of 0.8 and 1.0 Mg m À3 . On the other hand, almost the same value of hydraulic conductivity was obtained at the dry density around 1.2 Mg m À3 . This different effect of exchangeable cations on the hydraulic conductivity of montmorillonite could be attributed to the different sizes of macropores in compacted montmorillonite and/or the different thicknesses of electrical double layers formed over montmorillonite sheets.

show abstract

“…These experiments were designed to produce extreme conditions to favour smectite alteration with high Fe 2+ activities rather than to simulate repository conditions. It has also been suggested that dissolved Fe may replace Na + from smectite layers (Kamei et al, 1999). In experiments 2-1, 2-2, and 2-3, the Fe 2+ concentration was approximately twice that required to saturate the interlayers, whereas in experiments 4-6, the concentration was sufficient to replace only half of the interlayer sorption sites.…”

Section: Experimental Parametersmentioning

confidence: 96%

The effect of iron on montmorillonite stability. (II) Experimental investigation

Wilson

Cressey

et al. 2006

Geochimica et Cosmochimica Acta

100

View full text Add to dashboard Cite

Fe(II)–Na ion exchange at interlayers of smectite: adsorption–desorption experiments and a natural analogue

Cited by 50 publications

References 2 publications

Electron transfer at the mineral/water interface: Selenium reduction by ferrous iron sorbed on clay

Electron transfer at the mineral/water interface: Selenium reduction by ferrous iron sorbed on clay

A Study on Hydraulic Properties of Compacted Fe(III)-montmorillonite

The effect of iron on montmorillonite stability. (II) Experimental investigation

Contact Info

Product

Resources

About