Generation and stability of bentonite colloids at the bentonite/granite interface of a deep geological radioactive waste repository

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doi: 10.1016/S0169-7722(02)00110-9
Authors:Missana, Tiziana; Alonso, Úrsula; Turrero, María Jesús
Author Affiliations:Primary:
CIEMAT, Departamento de Impacto Ambiental de la Energia, Madrid, Spain
Volume Title:8th international conference on Chemistry and migration behaviour of actinides and fission products in the geosphere; Migration '01
Volume Authors:Kim, Jae-Il, editor; Geckeis, Horst
Source:Journal of Contaminant Hydrology, 61(1-4), p.17-31; 8th international conference on Chemistry and migration behaviour of actinides and fission products in the geosphere; Migration '01, Bregenz, Austria, Sept. 16-21, 2001, edited by Jae-Il Kim and Horst Geckeis. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0169-7722
Publication Date:2003
Note:In English. 35 refs.; illus., incl. 1 table
Summary:The possible mechanisms of colloid generation at the near field/far field interface of a radioactive repository have been investigated by means of novel column experiments simulating the granite/bentonite boundary, both in dynamic and in quasi-static water flow conditions. It has been shown that solid particles and colloids can be detached from the bulk and mobilised by the water flow. The higher the flow rate, the higher the concentration of particles found in the water, according to an erosion process. However, the gel formation and the intrinsic tactoid structure of the clay play an important role in the submicron particle generation even in the compacted clay and in a confined system. In fact, once a bentonite gel is formed, in the regions where the clay is contacted with water, clay colloids can be formed even in quasi-static flow conditions. The potential relevance of these colloids in radionuclide transport has been studied by evaluating their stability in different chemical environments. The coagulation kinetics of natural bentonite colloids was experimentally studied as a function of the ionic strength and pH, by means of time-resolved light scattering techniques. It has been shown that these colloids are very stable in low saline (∼1×10-3 M) and alkaline (pH≥8) waters. Abstract Copyright (2003) Elsevier, B.V.
Subjects:Alkalinity; Bentonite; Clastic rocks; Colloidal materials; Concentration; Controls; Dynamic properties; Experimental studies; Gels; Granites; Igneous rocks; Kinetics; Migration of elements; Parent materials; PH; Physicochemical properties; Plutonic rocks; Pollution; Radioactive waste; Sedimentary rocks; Simulation; Stability; Underground disposal; Waste disposal; Waste disposal sites; Water quality
Record ID:2003043691
Copyright Information:GeoRef, Copyright 2018 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands
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