Pertechnetate diffusion in GMZ bentonite

Li, J. Y.; Dai, Wei; Xiao, Guoping; Wang, H.; Zhang, Z. T.; Wu, Tao

doi:10.1007/s10967-012-1733-y

Cited by 16 publications

(5 citation statements)

References 26 publications

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“…Moreover, a SPSS statistical analysis (ANOVA) showed that obvious influences or significant differences were found for the various densities and radionuclides. These results also showed good agreement with those of previous studies [11,12,14,40,41], where the obvious differences in the diffusion parameters derived in the TD experiments could only be attributed to test conditions such as the cation…”

Section: Discussionsupporting

confidence: 92%

A Statistical Evaluation to Compare and Analyze Estimations of the Diffusion Coefficient of Pertechnetate (99TcO4−) in Compacted Bentonite

et al. 2021

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Various numerical methods have been being extensively used to estimate the diffusion parameters of pertechnetate (99TcO4−) in compacted MX80 bentonite clay using through-diffusion (TD) techniques. In this study, an improved TD column test was applied, and the diffusion fluxes of tritium (HTO) as a non-reactive radionuclide, and 99TcO4− with various dry densities, were compared under the same experimental conditions. Similar results were obtained for the apparent diffusion coefficients of HTO and 99TcO4− using three estimation methods: a graphical method applying the asymptote calculation, an analytical solution using Lsqcurvefit installed in MATLAB, and the Marquardt–Levenberg optimization algorithm in the HYDRUS-1D inverse method. The statistical analysis showed that the densities using a one-way analysis of variance (ANOVA) for the three estimation methods ranged from 1200 to 2000 kg/m3, which indicated that there were no obvious differences between HTO and 99TcO4−. In general, the diffusion parameters of 99TcO4− were lower than those for HTO due to anion exclusion effects and lower accessible porosity.

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Section: Discussionsupporting

confidence: 92%

A Statistical Evaluation to Compare and Analyze Estimations of the Diffusion Coefficient of Pertechnetate (99TcO4−) in Compacted Bentonite

et al. 2021

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“…ReO 4 was the predominant species under ambient conditions. a Data from (Wu et al, 2014) b Data from (Li et al, 2012b) c Data from (Wu et al, 2012b) d Data from (Molera et al, 2003) f Data from (Van Loon et al, 2007) For ReO 4 -, whose predominant species was ReO 4 in the pH range of 3.0 -10.0,…”

Section: Diffusion Experimentsmentioning

confidence: 99%

“…Li et al (2012) observed that the D e values of 99 TcO 4 in Beishan granite were (0.973 -1.31) × 10 -12 m 2 /s at pH 3.0 -10.0. 99 TcO 4 has been observed to be a non-sorbing species in bentonite (Li et al, 2012b). However, weak sorption of 99 TcO 4 was found by Zhao et al (2012) and Li et al (2012), which may be related to uncertainties arising from the different experimental set-up and data processing in bentonite and granite.…”

Section: Introductionmentioning

confidence: 95%

“…To avoid radioactivity, stable species such as rhenium and selenium are often used as surrogates for 99 Tc and 79 Se (Wu et al, 2014). The valence states of 99 Tc and Re can change from VII to III (Boggs et al, 2011;Li et al, 2012b;Rard, 2005). Both 99 Tc and Re exist mainly as two stable oxidation states, i.e., Tc(IV)/Tc(VII) or Re(IV)/Re(VII), in the environment.…”

Section: Introductionmentioning

confidence: 99%

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pH effect on Re(VII) and Se(IV) diffusion in compacted GMZ bentonite

Wang

et al. 2016

Applied Geochemistry

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“…Capillary method study 99 TcO 4 diffusion in compacted bentonite from Gaomiaozi County found that K d values from capillary teats are lower than those from batch tests and K d is a strong function of dry density of the compacted bentonite [3]. 99 TcO 4 diffusion in GMZ bentonite by through-and out-diffusion methods found that part of 99 TcO 4 may be reduced by Fe(II) and D a and dry density is exponential [5]. Electromigration experiments indicated that D a for selenate is range from 1.7×10 -11 to 6.2×10 -11 m 2 s -1 and no reduction of selenate [4].…”

Section: Introductionmentioning

confidence: 99%

Through-and Out-Diffusion of Se(IV) and Re(VII) in Compacted Bentonite

Wang

Jiang³

et al. 2014

AMR

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Through-diffusion and out-diffusion are good way to understand anion diffusion behavior in compacted bentonite. In the present work we investigated Re (VII) and Se (IV) diffusion behavior in 2000 kg/m3 compacted GMZ bentonite. The De values of Re (VII) and Se (IV) are 0.29 ± 0.02 and 0.77 ± 0.05× 10-11 m2/s. The result obtained from out-diffusion method was not agreed with predicted data due to the heterogeneous porosity distribution in clay boundaries and species changed when the diffusion occurred in GMZ bentonite. Comparing the Da values of Se, Tc and I in GMZ and Kunigel-F bentonites, it showed that Kunigel-F bentonite hindered the mobilities of anion more efficiently than GMZ bentonite because of the higher content of montmorillonite.

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Pertechnetate diffusion in GMZ bentonite

Cited by 16 publications

References 26 publications

A Statistical Evaluation to Compare and Analyze Estimations of the Diffusion Coefficient of Pertechnetate (99TcO4−) in Compacted Bentonite

A Statistical Evaluation to Compare and Analyze Estimations of the Diffusion Coefficient of Pertechnetate (99TcO4−) in Compacted Bentonite

pH effect on Re(VII) and Se(IV) diffusion in compacted GMZ bentonite

Through-and Out-Diffusion of Se(IV) and Re(VII) in Compacted Bentonite

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