Evaluation of rare earth on layered silicates under subcritical conditions: Effect of the framework and interlayer space composition
Clay-based minerals are considered to be an important component in backfill barriers due to both their ability to seal and adsorb radioactive waste and to interact chemically with it under subcritical conditions. Herein, we describe a systematic study of the properties of layered silicates that coul...
| Authors: | ; ; ; ; |
|---|---|
| Format: | Article |
| Status: | Submitted version |
| Publication date: | 2013 |
| Country: | España |
| Institution: | Universidad de Sevilla (US) |
| Repository: | idUS. Depósito de Investigación de la Universidad de Sevilla |
| OAI Identifier: | oai:idus.us.es:11441/70496 |
| Online Access: | https://hdl.handle.net/11441/70496 https://doi.org/10.1016/j.chemgeo.2013.03.006 |
| Access Level: | Open access |
| Keyword: | Subcritical conditions Hydrothermal 35 treatment Rare-earth Radioactive waste Engineered barrier X-ray diffraction MAS-NMR Disilicates Bentonite Smectite |
| _version_ | 1878736010716643328 |
|---|---|
| author | Chain Villar, Pablo |
| author2 | Cota Reguero, Agustín Pavón González, Esperanza Pazos Zarama, Mery Carolina Alba Carranza, María Dolores |
| author2_role | author author author author |
| author_browse | Alba Carranza, María Dolores Chain Villar, Pablo Cota Reguero, Agustín Pavón González, Esperanza Pazos Zarama, Mery Carolina |
| author_facet | Chain Villar, Pablo Cota Reguero, Agustín Pavón González, Esperanza Pazos Zarama, Mery Carolina Alba Carranza, María Dolores |
| author_role | author |
| collection | idUS. Depósito de Investigación de la Universidad de Sevilla |
| description | Clay-based minerals are considered to be an important component in backfill barriers due to both their ability to seal and adsorb radioactive waste and to interact chemically with it under subcritical conditions. Herein, we describe a systematic study of the properties of layered silicates that could affect their hydrothermal reactivity, namely type of layers, octahedral occupancy, origin and total amount of the layer charge, and nature of the interlayer cation. The silicates studied were selected on the basis of their different characteristics associated with these properties and were treated hydrothermally at 300 °C for 48 h in a 7.3 · 10− 2 M Lu(NO3)3 · 3.6H2O solution. The final products were analyzed by X-ray diffraction and solid-state NMR spectroscopy. All the layered silicates studied were found to be able to generate a Lu2Si2O7 phase after hydrothermal treatment under subcritical conditions, thereby confirming the participation of a chemical mechanism of the clay barrier generating phases being stables with temperature and pH conditions. However, the extent of this reaction depends to a large extent on the physicochemical properties of the framework and the interlayer space composition, such as the presence or absence of an octahedral sheet, the degree of occupancy of this sheet, and the origin and total layer charge. Therefore, this study allows tuning the clay mineral framework characteristic that favors the rare earth cations (as trivalent actinide simulator) immobilization. |
| eu_rights_str_mv | openAccess |
| format | article |
| id | ES_87323ca33b5fc97b2865500a79bf40db |
| institution | Universidad de Sevilla (US) |
| instname_str | Universidad de Sevilla (US) |
| network_acronym_str | ES |
| network_name_str | España |
| oai_identifier_str | oai:idus.us.es:11441/70496 |
| publishDate | 2013 |
| publishDateSort | 2013 |
| publisher | Elsevier |
| publisherStr | Elsevier |
| reponame_str | idUS. Depósito de Investigación de la Universidad de Sevilla |
| spelling | Evaluation of rare earth on layered silicates under subcritical conditions: Effect of the framework and interlayer space composition Chain Villar, Pablo Cota Reguero, Agustín Pavón González, Esperanza Pazos Zarama, Mery Carolina Alba Carranza, María Dolores Subcritical conditions Hydrothermal 35 treatment Rare-earth Radioactive waste Engineered barrier X-ray diffraction MAS-NMR Disilicates Bentonite Smectite Clay-based minerals are considered to be an important component in backfill barriers due to both their ability to seal and adsorb radioactive waste and to interact chemically with it under subcritical conditions. Herein, we describe a systematic study of the properties of layered silicates that could affect their hydrothermal reactivity, namely type of layers, octahedral occupancy, origin and total amount of the layer charge, and nature of the interlayer cation. The silicates studied were selected on the basis of their different characteristics associated with these properties and were treated hydrothermally at 300 °C for 48 h in a 7.3 · 10− 2 M Lu(NO3)3 · 3.6H2O solution. The final products were analyzed by X-ray diffraction and solid-state NMR spectroscopy. All the layered silicates studied were found to be able to generate a Lu2Si2O7 phase after hydrothermal treatment under subcritical conditions, thereby confirming the participation of a chemical mechanism of the clay barrier generating phases being stables with temperature and pH conditions. However, the extent of this reaction depends to a large extent on the physicochemical properties of the framework and the interlayer space composition, such as the presence or absence of an octahedral sheet, the degree of occupancy of this sheet, and the origin and total layer charge. Therefore, this study allows tuning the clay mineral framework characteristic that favors the rare earth cations (as trivalent actinide simulator) immobilization. Dirección General de Investigaciones Científicas y Técnicas CTQ2010-14874 Elsevier https://hdl.handle.net/11441/70496 https://doi.org/10.1016/j.chemgeo.2013.03.006 |
| spellingShingle | Evaluation of rare earth on layered silicates under subcritical conditions: Effect of the framework and interlayer space composition Chain Villar, Pablo Subcritical conditions Hydrothermal 35 treatment Rare-earth Radioactive waste Engineered barrier X-ray diffraction MAS-NMR Disilicates Bentonite Smectite |
| status_str | submittedVersion |
| title | Evaluation of rare earth on layered silicates under subcritical conditions: Effect of the framework and interlayer space composition |
| title_full | Evaluation of rare earth on layered silicates under subcritical conditions: Effect of the framework and interlayer space composition |
| title_fullStr | Evaluation of rare earth on layered silicates under subcritical conditions: Effect of the framework and interlayer space composition |
| title_full_unstemmed | Evaluation of rare earth on layered silicates under subcritical conditions: Effect of the framework and interlayer space composition |
| title_short | Evaluation of rare earth on layered silicates under subcritical conditions: Effect of the framework and interlayer space composition |
| title_sort | Evaluation of rare earth on layered silicates under subcritical conditions: Effect of the framework and interlayer space composition |
| topic | Subcritical conditions Hydrothermal 35 treatment Rare-earth Radioactive waste Engineered barrier X-ray diffraction MAS-NMR Disilicates Bentonite Smectite |
| topic_facet | Subcritical conditions Hydrothermal 35 treatment Rare-earth Radioactive waste Engineered barrier X-ray diffraction MAS-NMR Disilicates Bentonite Smectite |
| url | https://hdl.handle.net/11441/70496 https://doi.org/10.1016/j.chemgeo.2013.03.006 |