Direct observation of cesium at the interlayer region in phlogopite mica

Okumura, Taiga; Tamura, Kenji; Fujii, Eiko; Yamada, Hirohisa; Kogure, Toshihiro

doi:10.1093/jmicro/dft045

Cited by 43 publications

(50 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…7c). The brightest contrast (Cs) is definitely that corresponding to the Cs-occupied interlayer, where each Cs column can be resolved with a separation of 4.5 Å ( Okumura et al, 2014). The medium contrast (K) corresponds to the K-occupied interlayer, or that in biotite, where spots corresponding to the K-columns can be faintly identified.…”

Section: Chemical Compositions and Xrd Patterns Of The Original Samplesmentioning

confidence: 99%

“…Several studies have reported that FES plays an important role in Cs sorption and retention (Sawhney, 1972;Zachara et al, 2002;McKinley et al, 2004). On the other hand, recent studies Okumura et al, 2014) have indicated that Cs penetrates deeply inside the crystals, along the interlayer regions by ion-exchange. In these studies, a high-resolu-tion transmission electron microscope (HRTEM) or a high-angle annular dark field scanning transmission electron microscope (HAADF-STEM) was used to visualize Cs-replaced interlayer regions.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Cs–sorption in weathered biotite from Fukushima granitic soil

Kikuchi

Mukai

Kuramata

et al. 2015

Journal of Mineralogical and Petrological Sciences

Self Cite

View full text Add to dashboard Cite

The sorption characteristics of cesium (Cs) ions into weathered biotite with biotite-vermiculite interstratification collected from weathered granodiorite in Fukushima Prefecture, Japan has been investigated. Both single crystals and crushed powder forms of the weathered biotite were experimentally reacted with 20-2000 ppm CsCl aqueous solutions, and analyzed by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM) to examine the distribution of Cs inside the crystals. From the XRD pattern, the proportion of vermiculite unit layers in the weathered biotite was estimated at~12%, with a tendency for segregation, and the whole XRD pattern was explained by the coexistence of biotite and vermiculite packets as well as the interstratified regions. Powder XRD of Cs-sorbed specimens showed that the 14.9 Å peak of the vermiculite packets was weakened at a low Cs concentration in the solution. Single crystals of the weathered biotite with a polished edge-surface were immersed in the CsCl solutions and examined using SEM and high-angular annular dark field (HAADF) imaging in STEM. Cs was not only incorporated in the vicinity of the exposed surface but also penetrated deeply inside the crystals. These analyses and observations revealed the Cs-sorption process in weathered biotite. At first, Cs preferentially replaced specific vermiculite interlayers in the vermiculite packets. With a higher Cs concentration in the solution, the Cs-substituted vermiculite interlayers increased in the vermiculite packets, and vermiculite layers interstratified in biotite also incorporated Cs.

show abstract

Section: Chemical Compositions and Xrd Patterns Of The Original Samplesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cs–sorption in weathered biotite from Fukushima granitic soil

Kikuchi

Mukai

Kuramata

et al. 2015

Journal of Mineralogical and Petrological Sciences

Self Cite

View full text Add to dashboard Cite

show abstract

“…For example, some studies have hypothesized that basal and slow sites have essentially the same NaACs exchange selectivity [4], whereas atomistic simulations suggest that Cs is much more selectively retained in anhydrous clay interlayers than on external basal surfaces [79]. The few geochemical modeling studies that described slow sites as distinct surface sites treated them as ideal cation exchangers [22,100] despite evidence that these sites, at least in some cases, form interstratified structures in which Cs displaces K in some interlayers but not in others [69]. Finally, the adsorption-desorption kinetics of the slow and high-affinity sites remain incompletely understood.…”

Section: Introductionmentioning

confidence: 99%

Molecular dynamics simulations of cesium adsorption on illite nanoparticles

Lammers

Bourg

Okumura

et al. 2017

Journal of Colloid and Interface Science

129

View full text Add to dashboard Cite

The charged surfaces of micaceous minerals, especially illite, regulate the mobility of the major radioisotopes of Cs (Cs, Cs,Cs) in the geosphere. Despite the long history of Cs adsorption studies, the nature of the illite surface sites remains incompletely understood. To address this problem, we present atomistic simulations of Cs competition with Na for three candidate illite adsorption sites - edge, basal plane, and interlayer. Our simulation results are broadly consistent with affinities and selectivities that have been inferred from surface complexation models. Cation exchange on the basal planes is thermodynamically ideal, but exchange on edge surfaces and within interlayers shows complex, thermodynamically non-ideal behavior. The basal planes are weakly Cs-selective, while edges and interlayers have much higher affinity for Cs. The dynamics of NaCs exchange are rapid for both cations on the basal planes, but considerably slower for Cs localized on edge surfaces. In addition to new insights into Cs adsorption and exchange with Na on illite, we report the development of a methodology capable of simulating fully-flexible clay mineral nanoparticles with stable edge surfaces using a well-tested interatomic potential model.

show abstract

“…A number of studies have suggested that FES, which formed around the edges of plate-like mica crystals during weathering, strongly and selectively sorb Cs. 7−9 Recently, however, Kogure et al 10 and Okumura et al 11 used high-resolution transmission electron microscopy (HRTEM) to directly observe Cs ions sorbed deeply in the interlayer region of vermiculite and phlogopite.…”

Section: ■ Introductionmentioning

confidence: 99%

Speciation of Radioactive Soil Particles in the Fukushima Contaminated Area by IP Autoradiography and Microanalyses

Mukai

Hatta

Kitazawa

et al. 2014

Environ. Sci. Technol.

Self Cite

131

View full text Add to dashboard Cite

Radioactive soil particles several tens of micrometers in size were collected from litter soil in the radiation contaminated area by the Fukushima nuclear plant accident and characterized using electron and X-ray microanalyses. The radioactive particles were discriminated by autoradiography using imaging plates (IP) on which microgrids were formed by laser ablation in order to find the particles under microscopy. Fifty radioactive particles were identified and classified into three types from their morphology and chemical composition, namely: (1) aggregates of clay minerals, (2) organic matter containing clay mineral particulates, and (3) weathered biotite originating from local granite. With respect to the second type, dissolution of the organic matter did not reduce the radiation, suggesting that the radionuclides were also fixed by the clay minerals. The weathered biotite grains have a plate-like shape with well-developed cleavages inside the grains, and kaolin group minerals and goethite filling the cleavage spaces. The reduction of the radiation intensity was measured before and after the trimming of the plate edges using a focused ion beam (FIB), to examine whether radioactive cesium primarily sorbed at frayed edges. The radiation was attenuated in proportion to the volume decrease by the edge trimming, implying that radioactive cesium was sorbed uniformly in the porous weathered biotite.

show abstract

Direct observation of cesium at the interlayer region in phlogopite mica

Cited by 43 publications

References 18 publications

Cs–sorption in weathered biotite from Fukushima granitic soil

Cs–sorption in weathered biotite from Fukushima granitic soil

Molecular dynamics simulations of cesium adsorption on illite nanoparticles

Speciation of Radioactive Soil Particles in the Fukushima Contaminated Area by IP Autoradiography and Microanalyses

Contact Info

Product

Resources

About