Fuller, AJ, Shaw, S, Peacock, CL orcid.org/0000-0003-3754-9294 et al. (4 more authors) (2014) Ionic strength and pH dependent multi-site sorption of Cs onto a micaceous aquifer sediment. Applied Geochemistry, 40. pp. 32-42. ISSN 0883-2927
Abstract
Caesium-137 (t1/2 = 30 years) is a common contaminant at nuclear legacy sites. Often the mobility of 137Cs in the environment is governed by its sorption to charged sites within the sediment. To this end it is important to understand the sorption behaviour of caesium across a wide range of environmental conditions. This work investigates the effect of varying solution composition (pH and competing ions) on the sorption of caesium to micaceous aquifer sediment across a large concentration range (1.0 × 10−11 – 1.0 × 10−1 mol L−1 Cs+). Experimental results show that Cs+ exhibits three distinct sorption behaviours at three different concentration ranges. At very low concentrations < 1.0 × 10−6 mol L−1 Cs+ sorption was unaffected by competition with Na+ or H+ but significantly reduced in high ionic strength K+ solution. Secondly between 1 × 10−6 and 1.0 × 10−3 mol L−1 Cs+ is strongly sorbed in a neutral pH, low ionic strength background but sorption is significantly reduced in solutions with either a high concentration of Na+ or K+ ions or low pH. At high concentrations > 1.0 × 10−3 mol L−1 Cs+ sorption is reduced in all systems due to saturation of the sediment’s sorption capacity. A multi-site cation exchange model was used to interpret the sorption behaviour. From this it was determined that at low concentrations Cs+ sorbs to the illite frayed edge sites only in competition with K+ ions. However, once the frayed edge sites are saturated the Cs+ sorbs to the Type II and Planar sites in competition with K+, Na+ and H+ ions. Therefore sorption of Cs+ at concentrations > 1.0 × 10−6 mol L−1 is significantly reduced in both high ionic strength and low pH solutions. This is a significant result with regard to predicting the migration of 137Cs+ in acidic or high ionic strength groundwaters.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | (c) 2013 The Authors. Published by Elsevier Ltd.This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Earth Surface Science Institute (ESSI) (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 29 Sep 2014 12:25 |
Last Modified: | 15 Jan 2021 10:26 |
Published Version: | http://dx.doi.org/10.1016/j.apgeochem.2013.10.017 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.apgeochem.2013.10.017 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:80294 |