University of Surrey

Test tubes in the lab Research in the ATI Dance Research

Solubility constraints affecting the migration of selenium through the cementitious backfill of a geological disposal facility

Felipe-Sotelo, M, Hinchliff, J, Evans, NDM and Read, D (2016) Solubility constraints affecting the migration of selenium through the cementitious backfill of a geological disposal facility Journal of Hazardous Materials, 305. pp. 21-29.

Full text not available from this repository.

Abstract

This work presents the study of the solubility of selenium under cementitious conditions and its diffusion, as SeO32−, through monolithic cement samples. The solubility studies were carried out under alkaline conditions similar to those anticipated in the near-field of a cement-based repository for low- and intermediate-level radioactive waste. Experiments were conducted in NaOH solution, 95%-saturated Ca(OH)2, water equilibrated with a potential backfill material (Nirex reference vault backfill, NRVB) and in solutions containing cellulose degradation products, with and without reducing agents. The highest selenium concentrations were found in NaOH solution. In the calcium-containing solutions, analysis of the precipitates suggests that the solubility controlling phase is Ca2SeO3(OH)2·2H2O, which appears as euhedral rhombic crystals. The presence of cellulose degradation products caused an increase in selenium concentration, possibly due to competitive complexation, thereby, limiting the amount of calcium available for precipitation. Iron coupons had a minor effect on selenium solubility in contrast to Na2S2O4, suggesting that effective reduction of Se(IV) occurs only at Eh values below −300 mV. Radial through-diffusion experiments on NRVB and in a fly ash cement showed no evidence of selenium breakthrough after one year. However, autoradiography of the exposed surfaces indicated that some migration had occurred and that selenium was more mobile in the higher porosity backfill than in the fly ash cement.

Item Type: Article
Subjects : Chemistry
Authors :
NameEmailORCID
Felipe-Sotelo, MUNSPECIFIEDUNSPECIFIED
Hinchliff, JUNSPECIFIEDUNSPECIFIED
Evans, NDMUNSPECIFIEDUNSPECIFIED
Read, Dd.read@surrey.ac.ukUNSPECIFIED
Date : March 2016
Identification Number : 10.1016/j.jhazmat.2015.11.024
Copyright Disclaimer : © 2015 Elsevier B.V. All rights reserved.
Uncontrolled Keywords : Selenium, Solubility, Through-diffusion, Cement, Cellulose degradation products
Depositing User : Symplectic Elements
Date Deposited : 17 May 2017 13:58
Last Modified : 18 May 2017 12:54
URI: http://epubs.surrey.ac.uk/id/eprint/841037

Actions (login required)

View Item View Item

Downloads

Downloads per month over past year


Information about this web site

© The University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom.
+44 (0)1483 300800