Complexation of Sn with Boom Clay natural organic matter under nuclear waste repository conditions

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Complexation of Sn with Boom Clay natural organic matter under nuclear waste repository conditions. / Durce, Delphine; Salah, Sonia; Wang, Lian; Maes, Norbert.

In: Applied Geochemistry, Vol. 123, 104775, 01.12.2020, p. 1-9.

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@article{8ac720f3251445638039e80397253f56,
title = "Complexation of Sn with Boom Clay natural organic matter under nuclear waste repository conditions",
abstract = "126Sn is a long-lived fission product and as such a waste relevant radioisotope. Understanding its fate under deepgeologicalrepository conditions is a requirement for a complete safety assessment. Yet, due to a limited knowledge of its hydrogeochemical properties, the solubility and speciation of tin in a nuclear waste repository remain uncertain. In Belgium, Boom Clay (BC) is investigated as a potential host rock for high-level and intermediate level waste disposal. It contains a significant amount of dissolved organic matter (DOM), which was shown to strongly influence the mobility of several radionuclides and notably of tetravalent actinides. By chemical analogy, the speciation, sorption and mobility of Sn(IV) in BC is also assumed to be controlled by its binding to DOM. However, the Sn-DOM complexation has never been quantified under relevant repository conditions. In this work, the complexation of Sn with BC DOM was investigated under present-day BC conditions and in synthetic seawater as representative of more saline conditions. The ultrafiltration technique was used to quantify the amount of Sn bound to DOM. The two investigated repository conditions yielded nearly identical binding constants, evidencing a low influence of salinity on the level of binding of Sn to BC DOM. BC DOM forms strong complexes with Sn that would significantly increase Sn solubility in BC pore water. The investigated range of Sn and DOM concentrations (DOMtot/Sntot = 2.8 × 102 to 5.7 × 103) also showed that the binding constants are dependent on the metal loading (5.0 < logK(Sn{\^o}€€€ DOM) < 6.0). A two-site Langmuir isotherm was used to describe this dependency and highlighted the binding of Sn on both strong and weak sites present on DOM. Overall, the experimental data show that the binding of Sn with BC DOM controls the Sn speciation under BC repository conditions, which reveals the importance of taking it into account in safety assessment calculatio",
keywords = "Tin, Dissolved organic matter, Ultrafiltration, Complexation, BC",
author = "Delphine Durce and Sonia Salah and Lian Wang and Norbert Maes",
note = "Score=10",
year = "2020",
month = "12",
day = "1",
doi = "10.1016/j.apgeochem.2020.104775",
language = "English",
volume = "123",
pages = "1--9",
journal = "Applied Geochemistry",
issn = "0883-2927",
publisher = "Elsevier",

}

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TY - JOUR

T1 - Complexation of Sn with Boom Clay natural organic matter under nuclear waste repository conditions

AU - Durce, Delphine

AU - Salah, Sonia

AU - Wang, Lian

AU - Maes, Norbert

N1 - Score=10

PY - 2020/12/1

Y1 - 2020/12/1

N2 - 126Sn is a long-lived fission product and as such a waste relevant radioisotope. Understanding its fate under deepgeologicalrepository conditions is a requirement for a complete safety assessment. Yet, due to a limited knowledge of its hydrogeochemical properties, the solubility and speciation of tin in a nuclear waste repository remain uncertain. In Belgium, Boom Clay (BC) is investigated as a potential host rock for high-level and intermediate level waste disposal. It contains a significant amount of dissolved organic matter (DOM), which was shown to strongly influence the mobility of several radionuclides and notably of tetravalent actinides. By chemical analogy, the speciation, sorption and mobility of Sn(IV) in BC is also assumed to be controlled by its binding to DOM. However, the Sn-DOM complexation has never been quantified under relevant repository conditions. In this work, the complexation of Sn with BC DOM was investigated under present-day BC conditions and in synthetic seawater as representative of more saline conditions. The ultrafiltration technique was used to quantify the amount of Sn bound to DOM. The two investigated repository conditions yielded nearly identical binding constants, evidencing a low influence of salinity on the level of binding of Sn to BC DOM. BC DOM forms strong complexes with Sn that would significantly increase Sn solubility in BC pore water. The investigated range of Sn and DOM concentrations (DOMtot/Sntot = 2.8 × 102 to 5.7 × 103) also showed that the binding constants are dependent on the metal loading (5.0 < logK(Snô€€€ DOM) < 6.0). A two-site Langmuir isotherm was used to describe this dependency and highlighted the binding of Sn on both strong and weak sites present on DOM. Overall, the experimental data show that the binding of Sn with BC DOM controls the Sn speciation under BC repository conditions, which reveals the importance of taking it into account in safety assessment calculatio

AB - 126Sn is a long-lived fission product and as such a waste relevant radioisotope. Understanding its fate under deepgeologicalrepository conditions is a requirement for a complete safety assessment. Yet, due to a limited knowledge of its hydrogeochemical properties, the solubility and speciation of tin in a nuclear waste repository remain uncertain. In Belgium, Boom Clay (BC) is investigated as a potential host rock for high-level and intermediate level waste disposal. It contains a significant amount of dissolved organic matter (DOM), which was shown to strongly influence the mobility of several radionuclides and notably of tetravalent actinides. By chemical analogy, the speciation, sorption and mobility of Sn(IV) in BC is also assumed to be controlled by its binding to DOM. However, the Sn-DOM complexation has never been quantified under relevant repository conditions. In this work, the complexation of Sn with BC DOM was investigated under present-day BC conditions and in synthetic seawater as representative of more saline conditions. The ultrafiltration technique was used to quantify the amount of Sn bound to DOM. The two investigated repository conditions yielded nearly identical binding constants, evidencing a low influence of salinity on the level of binding of Sn to BC DOM. BC DOM forms strong complexes with Sn that would significantly increase Sn solubility in BC pore water. The investigated range of Sn and DOM concentrations (DOMtot/Sntot = 2.8 × 102 to 5.7 × 103) also showed that the binding constants are dependent on the metal loading (5.0 < logK(Snô€€€ DOM) < 6.0). A two-site Langmuir isotherm was used to describe this dependency and highlighted the binding of Sn on both strong and weak sites present on DOM. Overall, the experimental data show that the binding of Sn with BC DOM controls the Sn speciation under BC repository conditions, which reveals the importance of taking it into account in safety assessment calculatio

KW - Tin

KW - Dissolved organic matter

KW - Ultrafiltration

KW - Complexation

KW - BC

UR - https://ecm.sckcen.be/OTCS/llisapi.dll/open/41515064

U2 - 10.1016/j.apgeochem.2020.104775

DO - 10.1016/j.apgeochem.2020.104775

M3 - Article

VL - 123

SP - 1

EP - 9

JO - Applied Geochemistry

JF - Applied Geochemistry

SN - 0883-2927

M1 - 104775

ER -

ID: 6978636