Influence of non-equilibrium sorption on the vertical migration of 137Cs in forest mineral soils of Fukushima Prefecture

2021 ◽  
Vol 232 ◽  
pp. 106567
Author(s):  
Hamza Chaif ◽  
Frédéric Coppin ◽  
Aya Bahi ◽  
Laurent Garcia-Sanchez
Keyword(s):  
Vertical Migration ◽  
Equilibrium Sorption ◽  
Fukushima Prefecture ◽  
Mineral Soils ◽  
Non Equilibrium

Influence of non-equilibrium sorption on the vertical migration of 137Cs in forest mineral soils of Fukushima prefecture

2021 ◽  
Author(s):  
Hamza Chaif ◽  
Frederic Coppin ◽  
Aya Bahi ◽  
Laurent Garcia-Sanchez
Keyword(s):  
Vertical Migration ◽  
Half Life ◽  
Mineral Soil ◽  
Terrestrial Ecosystems ◽  
Organic Layer ◽  
Soil Profiles ◽  
Sorption Model ◽  
Equilibrium Sorption ◽  
Sorption Parameters ◽  
Non Equilibrium

<p>Vertical migration of radiocesium is a key issue in soils impacted by Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. Among radioactive substances deposited on terrestrial ecosystems, <sup>134</sup>Cs (with half-life 2.07 years) and <sup>137</sup>Cs (with half-life 30.2 years) were dominant and have by far the most radiological significance.</p><p>This work investigates the importance of non-equilibrium sorption on the vertical migration of <sup>137</sup>Cs in field conditions. The equilibrium-kinetic (EK) sorption model was selected as a non-equilibrium parameterization embedding the K<sub>d</sub> approach. It supposes the existence of two types of sorption sites. The first sites are at equilibrium with solution; whereas for the second sites, kinetics of the sorption and desorption are taken into consideration.</p><p>We focused our study on four <sup>137</sup>Cs soil contamination plots measured in a young cedar stand situated around 35 km northwest of the FDNPP. Profiles were sampled at four different dates (2013, 2014, 2016, and 2018) by measuring <sup>137</sup>Cs activity in both organic (humus + litter layer) and mineral soil layers reaching a maximum depth of 20cm.</p><p>To successfully simulate the <sup>137</sup>Cs transfer throughout these soil profiles, the input flux at the top of the mineral soil surface was reconstructed from global monitoring data from the forest stand and a first-order compartment model for the organic layer.</p><p>Our results showed that the inclusion of non-equilibrium sorption slightly improves the realism of simulated <sup>137</sup>Cs profiles compared to the equilibrium hypothesis. While both models were able to reproduce the overall vertical distribution throughout the profiles, the persistent contamination at the surface was closer to the measured value with the EK approach. As a consequence, the K<sub>d</sub> model overestimated the contamination into deeper layers and therefore overestimated the migration velocity of <sup>137</sup>Cs. Fitted sorption parameters suggested a fast sorption kinetic (1 - 7 hours) and a pseudo-irreversible desorption rate (3.2 - 3.4 x 10<sup>6</sup> years), whereas equilibrium sorption (4.0 x 10<sup>-3</sup> L kg<sup>-1</sup> on average) only affected a negligible portion of <sup>137</sup>Cs inventory.</p><p>To further distinguish the models behaviors, short and long term simulations were conducted. By June 2011, EK parameters fitted on our plots realistically reproduced different profiles measured in the same forest study site. Predictive modeling of <sup>137</sup>Cs profiles in soil suggested a strong persistence of the surface <sup>137</sup>Cs contamination by 2030, with exponential profiles consistent with those reported after the Chernobyl accident.</p><p>These results prove that the choice of the sorption model is critical in post-accidental situations. An equilibrium approach can result in an underestimation of <sup>137</sup>Cs residence time in the surface. Whereas a kinetic approach, by distinguishing different sorption and desorption rates, is able to reproduce the slow evolution of <sup>137</sup>Cs soil profiles with time that is already observed in the case of Chernobyl contaminated areas 30 years after the accident. Non equilibrium sorption parameters can be partially inferred from in situ measurements. However, further experiments in controlled conditions are required to better estimate the sorption parameters and to identify the processes behind non-equilibrium sorption.</p>

Implications of non-equilibrium sorption on the interception–sorption trench remediation strategy

Geoderma ◽  
1998 ◽  
Vol 84 (1-3) ◽  
pp. 109-120 ◽  
Author(s):  
P.W Hitchcock ◽  
D.W Smith
Keyword(s):  
Equilibrium Sorption ◽  
Remediation Strategy ◽  
Non Equilibrium

Multi-zinc oxide-cores@uni-barium sulfate-shell with improved photo-, thermal-, and ambient-stability: Non-equilibrium sorption fabrication and light-emitting diodes application

2018 ◽  
Vol 529 ◽  
pp. 1-10 ◽  
Author(s):  
Ya-Chuan Liang ◽  
Kai-Kai Liu ◽  
Xue-Ying Wu ◽  
Xian-Li Lu ◽  
Ying-Jie Lu ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Barium Sulfate ◽  
Light Emitting Diodes ◽  
Equilibrium Sorption ◽  
Light Emitting ◽  
Non Equilibrium

scholarly journals Investigation of Analysis Methods for Pulse Decay Tests Considering Gas Adsorption

Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2562 ◽  
Author(s):  
Guofeng Han ◽  
Yang Chen ◽  
Xiaoli Liu
Keyword(s):  
Steady State ◽  
Gas Adsorption ◽  
Correction Method ◽  
Flow Coefficient ◽  
Dual Porosity ◽  
Unsteady State ◽  
Equilibrium Sorption ◽  
Adsorbed Phase ◽  
Decay Tests ◽  
Non Equilibrium

The pulse decay test is the main method employed to determine permeability for tight rocks, and is widely used. The testing gas can be strongly adsorbed on the pore surface of unconventional reservoir cores, such as shale and coal rock. However, gas adsorption has not been well considered in analysis pulse decay tests. In this study, the conventional flow model of adsorbed gas in porous media was modified by considering the volume of the adsorbed phase. Then, pulse decay tests of equilibrium sorption, unsteady state and pseudo-steady-state non-equilibrium sorption models, were analyzed by simulations. For equilibrium sorption, it is found that the Cui-correction method is excessive when the adsorbed phase volume is considered. This method is good at very low pressure, and is worse than the non-correction method at high pressure. When the testing pressure and Langmuir volume are large and the vessel volumes are small, a non-negligible error exists when using the Cui-correction method. If the vessel volumes are very large, gas adsorption can be ignored. For non-equilibrium sorption, the pulse decay characteristics of unsteady state and pseudo-steady-state non-equilibrium sorption models are similar to those of unsteady state and pseudo-steady-state dual-porosity models, respectively. When the upstream and downstream pressures become equal, they continue to decay until all of the pressures reach equilibrium. The Langmuir volume and pressure, the testing pressure and the porosity, affect the pseudo-storativity ratio and the pseudo-interporosity flow coefficient. Their impacts on non-equilibrium sorption models are similar to those of the storativity ratio and the interporosity flow coefficient in dual-porosity models. Like dual-porosity models, the pseudo-pressure derivative can be used to identify equilibrium and non-equilibrium sorption models at the early stage, and also the unsteady state and pseudo-steady-state non-equilibrium sorption models at the late stage. To identify models using the pseudo-pressure derivative at the early stage, the suitable vessel volumes should be chosen according to the core adsorption property, porosity and the testing pressure. Finally, experimental data are analyzed using the method proposed in this study, and the results are sufficient.

MATHEMATICAL MODELING OF NON-EQUILIBRIUM SORPTION

2016 ◽  
Vol 99 (12) ◽  
pp. 1803-1810
Author(s):  
I. A. Kaliev ◽  
S. T. Mukhambetzhanov ◽  
G. S. Sabitova
Keyword(s):  
Mathematical Modeling ◽  
Equilibrium Sorption ◽  
Non Equilibrium

scholarly journals Neumann boundary value problem for system of equations of non-equilibrium sorption

2019 ◽  
Vol 11 (4) ◽  
pp. 33-39
Author(s):  
Ibragim Adietovich Kaliev ◽  
Gul'nara Sagyndykovna Sabitova
Keyword(s):  
Boundary Value Problem ◽  
Boundary Value ◽  
Neumann Boundary ◽  
System Of Equations ◽  
Equilibrium Sorption ◽  
Neumann Boundary Value Problem ◽  
Non Equilibrium

scholarly journals Numerical modeling of the non-equilibrium sorption process

2016 ◽  
Vol 8 (2) ◽  
pp. 39-43 ◽  
Author(s):  
Ibragim Adietovich Kaliev ◽  
Saltanbek Talapedenovich Mukhambetzhanov ◽  
Gul'nara Sagyndykovna Sabitova
Keyword(s):  
Numerical Modeling ◽  
Sorption Process ◽  
Equilibrium Sorption ◽  
Non Equilibrium

Nuclide migration under non-equilibrium sorption in a rock matrix surrounding a repository

1984 ◽  
Vol 11 (12) ◽  
pp. 611-621 ◽  
Author(s):  
A.K. Ray ◽  
S. Nair
Keyword(s):  
Rock Matrix ◽  
Equilibrium Sorption ◽  
Non Equilibrium
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