The sorption of alkaline earth metals on biotite

Söderlund, Mervi; Ervanne, Heini; Muuri, Eveliina; Lehto, Jukka

doi:10.2343/geochemj.2.0561

Cited by 11 publications

(16 citation statements)

References 12 publications

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“…Thus, understanding the whole system of the bedrock matrix is of importance for the safety considerations of the disposal process. To this end, several key parameters of the crystalline rock in the disposal test sites have been studied extensively: porosity of the rock matrix and fracturation of Olkiluoto rocks (Kuva et al, 2012;Sammaljärvi et al, 2017), advection and flow properties with gas (Kuva, 2016) and in the water phase (Voutilainen et al, 2019), diffusion (Voutilainen et al, 2016(Voutilainen et al, , 2018Aromaa et al, 2019), and sorption (Ervanne et al, 2014;Muuri et al, 2016Muuri et al, , 2017Söderlund et al, 2019). Furthermore, the matrix diffusion (Neretnieks, 2013;Tsang et al, 2015), flow (Liu et al, 2018;Neretnieks and Winberg-Wang, 2019), and advection (Shahkarami et al, 2015) of radionuclides in saturated rock and rock fractures have been reported previously.…”

Section: Introductionmentioning

confidence: 99%

Radium sorption on biotite; surface complexation modeling study

Fabritius

Puhakka

et al. 2022

Applied Geochemistry

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Section: Introductionmentioning

confidence: 99%

Radium sorption on biotite; surface complexation modeling study

Fabritius

Puhakka

et al. 2022

Applied Geochemistry

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“…Sorption of cations, such as Cs + , Sr 2+ and Co 2+ , is known to be strong on biotite, which will retard their migration processes through rock samples [36][37][38][39]. Three voltages (2V, 3V and 4V) over the rock sample were applied in the electromigration experiments with SrCl 2 using the modified electromigration device.…”

Section: Electromigration Results With Srclmentioning

confidence: 99%

Diffusion and Sorption Studies of Cs, Sr and Co in Intact Crystalline Rock

Sammaljärvi

Meng

et al. 2022

Minerals

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Three cationic tracers, Sr2+, Co2+ and Cs+ were tested with a modified electromigration device by applying 2V, 3V and 4V voltage gradients over an intact Grimsel granodiorite rock sample. An ideal plug-flow model and an advection-dispersion model were applied to analyze the breakthrough curves. Matrix characterization by C-14-PMMA autoradiography and scanning electron microscopy showed that in the centimeter scale of Grimsel granodiorite rock, the interconnected matrix porosity forms a well-connected network for diffusion. Micrometer-scale fissures are transecting biotite and chlorite minerals, indicating sorption of the studied cations. The ideal plug-flow model indicated that the effective diffusion coefficients (De values) for Sr2+, Co2+ and Cs+ tracer ions within the Grimsel granodiorite rock were 3.20 × 10−13 m2/s, 1.23 × 10−13 m2/s and 2.25 × 10−12 m2/s, respectively. De values were also derived from the advection-dispersion model, from which 2.86 × 10−13 m2/s, 1.35 × 10−13 m2/s and 2.26 × 10−12 m2/s were calculated. The diffusion speed for the tracers was in the sequence of Cs+ > Sr2+ > Co2+ that is in the same sequence as their diffusion in diluted water. The distribution coefficients (Kd values) calculated from the models covered the range of two magnitudes (from 10−7 m3/kg to 10−5 m3/kg). The result indicated that the sorption process of the studied elements did not reach equilibrium during the electromigration process, mainly due to the too much acceleration of the migration speed by the voltage gradients applied over the rock sample.

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“…NaCl solution was used to keep the ionic strength constant and the concentration 0.01 M was selected because the same concentration was used in the previous electromigration sorption experiments (Puukko et al., 2018). In these conditions, the speciation of Cs and Sr are Cs + and Sr 2+ (Hakanen et al., 2012; Söderlund et al., 2019). The solutions were equilibrated in 20 ml plastic vials for a week.…”

Section: Methodsmentioning

confidence: 99%

“…To these ends, it is important to study the behavior of Cs and Sr in contact with groundwater and bedrock. Cs and Sr exist as cations in the ground water solutions (Cs + and Sr 2+ ) (Hakanen et al., 2012; Söderlund et al., 2019) and their sorption mechanism is ion exchange (Liu et al., 2004; Cho and Sridhar Komarneni, 2009). Sorption of these nuclides on crystalline rocks has been studied widely using samples from different sites e.g.…”

Section: Introductionmentioning

confidence: 99%

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Batch sorption experiments of cesium and strontium on crushed rock and biotite for the estimation of distribution coefficients on intact crystalline rock

Lehto

Puukko

Lindberg

et al. 2019

Heliyon

Self Cite

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The distribution coefficient (K d) of radionuclides on bedrock is one of the key parameters used in the safety analysis of spent nuclear fuel repositories. Typically, distribution coefficients have been determined using crushed rock. However, recent studies have shown that crushing of the rock increases considerably the distribution coefficient compared with the values of intact rock. This study aimed to test if batch sorption experiments using different grain sizes (i.e. mean diameter of grains) can be used to evaluate the K d of strontium (Sr) and cesium (Cs) on intact crystalline rock, which would decrease the needed experimental time compared with transport experiments. Here we report the results of the batch sorption experiments with crushed rocks and compare the results with those from a recent study performed using electromigration experiments with intact drill core samples (Puukko et al., 2018). The batch sorption experiments were done for rock samples from Olkiluoto, Finland, as a function of grain size and of Cs and Sr concentration. Furthermore, the specific surface areas of the same rock samples with different grain sizes were determined. It was shown that Cs distribution coefficients correlate with specific surface areas of the studied rocks and biotite, the correlation coefficient being 0.95. The Cs distribution coefficient was highest for biotite at about 0.1 m 3 /kg at 10 À4 M cesium concentration and increased systematically to about 1 m 3 /kg at 10 À8 M. Distribution coefficients for rocks were up to about two orders of magnitude lower, being lowest with the rock with the lowest biotite content (3.3%). The distribution coefficient of Sr varied from 0.04 m 3 /kg to 0.007 m 3 /kg and behaved in a different manner: it remained constant in two out of three studied rocks in the concentration range of 10 À8-10 À4 M and only in the case of one rock a decreasing trend was seen at the higher concentration range. It was also shown that batch sorption experiments overestimate the distribution coefficient in respect to intact rock. The decrease of the distribution coefficient as a function of grain size can be estimated using a power law function. It was also shown that estimation of distribution coefficients of Cs and Sr for intact rock by extrapolation of distribution coefficients determined for different grain sizes is not possible without increasing grain size, but in that case diffusion into the grains would also affect the results. A new method was developed for estimating the fraction of the inner surface area of the total surface area of crushed grains. For the mean grain sizes of 0.25 mm and 0.75 mm the fraction of the inner surface was found to be 35-70% and 60-90%, respectively. The inner specific surface area was highest with biotite at 1.2 m 2 /g and lowest with the rock with lowest biotite content (3.3%) at 0.07 m 2 /g. The surface area analysis revealed that crushing creates and/or allows access to additional inner surface area that is not measured in intact rock. Furthermore, it was demonstr...

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The sorption of alkaline earth metals on biotite

Cited by 11 publications

References 12 publications

Radium sorption on biotite; surface complexation modeling study

Radium sorption on biotite; surface complexation modeling study

Diffusion and Sorption Studies of Cs, Sr and Co in Intact Crystalline Rock

Batch sorption experiments of cesium and strontium on crushed rock and biotite for the estimation of distribution coefficients on intact crystalline rock

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