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Zuo R, Xu Z, Wang X, Yang J, Du X, Du C, Cai W, Xu Y, Wu Z. Adsorption characteristics of strontium by bentonite colloids acting on claystone of candidate high-level radioactive waste geological disposal sites. Environ Res 2022; 213:113633. [PMID: 35700766 DOI: 10.1016/j.envres.2022.113633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 05/30/2022] [Accepted: 06/05/2022] [Indexed: 06/15/2023]
Abstract
The bentonite colloid produced in the deep geological repository of high-level radioactive waste can directly affect the migration of radionuclide strontium when it acts on claystone. The adsorption characteristics of strontium were investigated on claystone with the presence or absence of bentonite colloids from the Suhongtu area of China. The effects of different influencing factors, such as pH and solid content, on the adsorption process were investigated by batch adsorption experiments, and spectroscopic techniques were used to characterize the samples before and after adsorption of strontium. The results show that the presence of bentonite colloids can promote the adsorption of strontium on claystone under alkaline conditions. and the general order kinetic model provided the best fit to the experimental data. Strontium is adsorbed on the surface of claystone and bentonite colloid by ion exchange and surface complexation. Most of the Sr2+ formed SrCO3 with CO32- after ion exchange with Ca2+ and Mg2+ in plagioclase and dolomite, and a small amount of Sr2+ was adsorbed by complexation with -OH, Al-O and Si-O. These results provide a scientific basis for predicting the migration of strontium in subsurface porous media and the siting of high-level radioactive waste repositories.
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Affiliation(s)
- Rui Zuo
- College of Water Sciences, Beijing Normal University, Beijing, 100875, China; Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, Beijing, 100875, China
| | - Zuorong Xu
- College of Water Sciences, Beijing Normal University, Beijing, 100875, China; Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, Beijing, 100875, China
| | - Xin Wang
- Jinan Rail Transit Group Co., Ltd., Jinan, 250000, China
| | - Jie Yang
- College of Water Sciences, Beijing Normal University, Beijing, 100875, China; Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, Beijing, 100875, China.
| | - Xiaofeng Du
- Shandong Rail Transit Engineering Consulting Co., Ltd., Jinan, 250000, China
| | - Can Du
- Development and Research Center, China Geological Survey, Beijing, 100037, China
| | - Weihai Cai
- College of Water Sciences, Beijing Normal University, Beijing, 100875, China; Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, Beijing, 100875, China
| | - Yunxiang Xu
- College of Water Sciences, Beijing Normal University, Beijing, 100875, China; Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, Beijing, 100875, China
| | - Ziyi Wu
- College of Water Sciences, Beijing Normal University, Beijing, 100875, China; Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, Beijing, 100875, China
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Rasamimanana S, Lefèvre G, Dagnelie RVH. Adsorption of polar organic molecules on sediments: Case-study on Callovian-Oxfordian claystone. Chemosphere 2017; 181:296-303. [PMID: 28448911 DOI: 10.1016/j.chemosphere.2017.04.086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 04/04/2017] [Accepted: 04/19/2017] [Indexed: 06/07/2023]
Abstract
The release and transport of anthropogenic organic matter through the geosphere is often an environmental criterion of safety. Sedimentary rocks are widely studied in this context as geological barriers for waste management. It is the case of Callovian-Oxfordian claystone (COx), for which several studies report adsorption of anthropogenic organic molecules. In this study, we evaluated and reviewed adsorption data of polar organic molecules on COx claystone. Experiments were performed on raw claystone, decarbonated and clay fractions. Adsorption isotherms were measured with adsorbates of various polarities: adipate, benzoate, ortho-phthalate, succinate, gluconate, oxalate, EDTA, citrate. A significant adsorption was observed for multidentate polycarboxylic acids as evidenced with phthalate, succinate, oxalate, gluconate, EDTA and citrate (Rd = 1.53, 3.52, 8.4, 8.8, 12.4, 54.7 L kg-1 respectively). Multiple linear regression were performed as a statistical analysis to determine the predictors from these adsorption data. A linear correlation between adsorption data (Rd) and dipole moment (μ) of adsorbates was evidenced (R2 = 0.91). Molecules with a high dipole moment, μ(D) > 2.5, displayed a significant adsorption, Rd≫1 L kg-1. A qualitative correlation can be easily estimated using the water/octanol partition coefficient, Pow, of adsorbates (R2 = 0.77). In this case, two opposite trends were distinguished for polar and apolar molecules. The use of organic carbon content in sediments is relevant for predicting adsorption of apolar compounds, log (Pow)>+1. The oxides/clays contents may be relevant regarding polar molecules, log (apparentPow)<-1. The proposed scheme offers a general methodology for investigation of geo-barriers towards heterogeneous organic plumes.
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Affiliation(s)
- S Rasamimanana
- DEN-Service d'Etude du Comportement des Radionucléides (SECR), CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette, France.
| | - G Lefèvre
- PSL Research University, Chimie ParisTech-CNRS, Institut de Recherche de Chimie Paris, 11 rue Pierre et Marie Curie, F-75005, Paris, France
| | - R V H Dagnelie
- DEN-Service d'Etude du Comportement des Radionucléides (SECR), CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette, France
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