Cesium incorporation and diffusion in cancrinite, sodalite, zeolite, and allophane

Mon, Jarai; Deng, Youjun; Flury, Markus; Harsh, James B.

doi:10.1016/j.micromeso.2005.07.030

Cited by 105 publications

(62 citation statements)

References 17 publications

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“…Alteration in types of cation exchange site and affinity by weathering processes has been also suggested previously [31].…”

Section: Modeling Of Ion-exchange Reactions Various Types Of Ion-excsupporting

confidence: 60%

“…An additional minor breakthrough of Sr also occurred at 130 PV only in the HIcolumn ( Figure 2b), accompanied by breakthroughs of Cs, K, and Si (Figure 2b, 2c) and Al ( Figure S2) [12,15,31]. In addition, cementitious Al and Si end-products have been found as secondary minerals in hyperalkaline high ionic strength environments [21,34].…”

Section: Bpw Leachate Results From Thementioning

confidence: 94%

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Strontium and Cesium Release Mechanisms during Unsaturated Flow through Waste-Weathered Hanford Sediments

Chang

Rod

et al. 2011

Environ. Sci. Technol.

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TitleStrontium and cesium release mechanisms during unsaturated flow through wasteweathered Hanford sediments Cs. The mineral composition of the weathered sediments showed that zeolite (chabazite-type) and feldspathoid (sodalitetype) were the major byproducts but different contents depending on the weathering conditions.Reactive transport modeling indicated that Cs leaching was controlled by ion-exchange, while Sr release was affected primarily by dissolution of the secondary minerals. The later release of K, Al, and Si from the HI-column indicated the additional dissolution of a more crystalline mineral (cancrinite-type). A two-site ion-exchange model successfully simulated the Cs release from the LO-column. However, a three-site ion-exchange model was needed for the HI-column. The study implied that the weathering conditions greatly impact the speciation of the secondary minerals and leaching behavior of sequestrated Sr and Cs.3

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“…Alteration in types of cation exchange site and affinity by weathering processes has been also suggested previously [31].…”

Section: Modeling Of Ion-exchange Reactions Various Types Of Ion-excsupporting

confidence: 60%

Section: Bpw Leachate Results From Thementioning

confidence: 94%

Strontium and Cesium Release Mechanisms during Unsaturated Flow through Waste-Weathered Hanford Sediments

Chang

Rod

et al. 2011

Environ. Sci. Technol.

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“…A further, albeit smaller, maximum loss rate is observed in the DTG curve at 670 K. The DDSC curve (Supplementary Figure S1b) shows a strong endothermic peak at 311 K and a shoulder at 366 K. Additional, three endothermic peaks are observed at 484, 540 and 707 K. The total mass loss of ca. 25% (Supplementary Figure S1a) is significantly higher than that reported in reference data for erionite samples [1,7,17,37] that ranges from ca. 16.0 % to ca.…”

Section: Thermal Analyses (Supplementarycontrasting

confidence: 54%

“…Analogously to 8MR, the modification of the shape has been monitored following the evolution with temperature of the O1-O1 and O3-O3 bond distances. As it has been previously pointed out, despite the very small FDV, the effect of phonon modes on pore windows breathing [35,36] helps cation diffusion from the cancrinite cage, which has been experimentally demonstrated [37]. The dependence from temperature of O1-O1 and O3-O3 is like that observed in erionite-Na [20].…”

Section: Structural Modifications: Frameworksupporting

confidence: 51%

Thermal Stability of Woolly Erionite-K and Considerations about the Heat-Induced Behaviour of the Erionite Group

et al. 2018

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Abstract:The thermal behavior of a woolly erionite-K sample (Lander County, NV, USA), chemical formula (Ca 2.03 Si+Al ratio and T break . A higher Si content results in a greater thermal stability, in agreement with the general trend observed in zeolites. On the contrary, no correlation has been found between T break and weighted ionic potential (Z/r) wt as suggested by reference data. Heating produces a general depletion of the Ca1, Ca2, Ca3, and K1 sites, which is counterbalanced by an increase of the K2 site scattering, even though the latter is not populated at RT. No "internal ion exchange" mechanism was apparently acting in the present sample differently from other erionite samples analysed in the past. At 303 K approximately 20 e − allocated at the OW H 2 O sites might be assigned to (extra-framework) EF cations. Such fraction increases due to their migration from the extra-framework cation sites following the same mechanism reported in reference data.

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“…A 2.8 general mineral transformation pathway was observed in these studies: poorly crystalline aluminosilicate fi Linde Type A zeolite fi cancrinite/sodalite, with cancrinite and sodalite being the two stable phases (Deng et al 2006a). In earlier studies, the same group found that cancrinite, sodalite, LTA zeolite and allophane were identified as the new formation in these sediments (Mashal et al 2004;Mashal et al 2005b;Mon et al 2005). The soil mineral dissolution followed the order of quartz fi kaolinite fi illite, and although cancrinite, sodalite, and zeolite were formed, the zeolite was not detected after 25 days of reaction time (Mashal et al 2005a), indicating that this mineral underwent either dissolution or phase transformation.…”

Section: 7mentioning

confidence: 52%

Remediation of Uranium in the Hanford Vadose Zone Using Ammonia Gas: FY 2010 Laboratory-Scale Experiments

Szecsody¹,

Truex²,

Zhong³

et al. 2010

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Executive SummaryThis investigation is focused on refining an in situ technology for vadose zone remediation of uranium by the addition of ammonia (NH 3 ) gas with no addition of water. The objectives were to: a) refine the technique of ammonia gas treatment, b) identify the geochemical changes in uranium surface phases, c) identify broader geochemical changes that occur, and d) predict and test injection of ammonia gas for intermediate-scale systems to identify process interactions that could impact field-scale implementation. For ammonia gas injection into vadose zone sediments to be successful as a uranium remediation technology, it needs to show decreased U mobility of the most mobile U phases (aqueous, adsorbed) in a variety of field conditions. Uranium is present in Hanford sediment include in multiple phases including aqueous U(VI)-carbonate complexes, adsorbed, uranium coprecipitated with carbonates, and U-bearing minerals Na-boltwoodite and uranophane. Ammonia treatment of sediments raises the pH in Hanford sediments from 8.0 to 11-13, which has resulted in a decrease in uranium mobility, as evidenced by decrease in aqueous and adsorbed uranium in 85% of the different sediments tested (different U surface phase distributions or NH 3 treatments) and an increase in 8M HNO 3 extracted U (hard to extract U phases, silicates/phosphates/oxides) for 79% of sediments tested. There were also inconsistent changes in two acetate extractions, likely the result of dissolution of multiple surface U phases (U-carbonates, Na-boltwoodite, uranophane). Surface phase analysis by laser induced fluorescence spectroscopy and extended x-ray absorption structure has showed essentially no U surface mineral change in sediments initially containing Na-boltwoodite, but some U surface phase changes in U-calcite coprecipitates to uranyl oxyhydroxide, Na-boltwoodite, and uranyl tricarbonate. Therefore, the ammonia gas treatment appears most effective for U present in the most mobile phases: aqueous U, adsorbed U, and carbonate associated U. NH 3 -treated sediments containing Na-boltwoodite and uranophane showed decreased leaching even though solid phase analysis showed little changes in the U mineralogy. The decreased leaching may be the result of other mineral precipitates coating these phases. Minerals that leached the most significant mass of ions were montmorillonite, muscovite, and kaolinite. A greater understanding of these dissolution/precipitation/coating processes is needed to predict the long-term impact on uranium mobility.Ammonia gas injection experiments conducted in 20-to 30-ft long 1-D systems and a layered 2-D radial flow system were used to characterize the physicochemical changes at the NH 3 reaction front and treatment coverage in heterogeneous sediments. For 5% NH 3 (95%N 2 ) injection, an average of 234 pore volumes were needed to achieve the elevated pH (10.2 to 11.4) of the reaction front observed, with 465 pore volumes needed to achieve pH equilibrium (pH = 11.88), at 4% water content and 35% porosity. The des...

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Cesium incorporation and diffusion in cancrinite, sodalite, zeolite, and allophane

Cited by 105 publications

References 17 publications

Strontium and Cesium Release Mechanisms during Unsaturated Flow through Waste-Weathered Hanford Sediments

Strontium and Cesium Release Mechanisms during Unsaturated Flow through Waste-Weathered Hanford Sediments

Thermal Stability of Woolly Erionite-K and Considerations about the Heat-Induced Behaviour of the Erionite Group

Remediation of Uranium in the Hanford Vadose Zone Using Ammonia Gas: FY 2010 Laboratory-Scale Experiments

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