Physicochemical evolution of a geopolymer wasteform for immobilizing thermally treated spent ion exchange resins: structural changes and cesium leachability

Gianni F. Vettese; Taavi Vierinen; Laura Stefanini; Kathleen A. Law; You Cheng Khng; Sami Hietala; Juhani Virkanen; Suvi Lamminmäki; Tandré Oey; Tapio Vehmas; Matti Nieminen; Jaana Laatikainen-Luntama; Marianna Kemell; Gareth T.W. Law

doi:10.1007/s10967-025-10405-7

Physicochemical evolution of a geopolymer wasteform for immobilizing thermally treated spent ion exchange resins: structural changes and cesium leachability

Gianni F. Vettese^*
, Taavi Vierinen
, Laura Stefanini
, Kathleen A. Law
, You Cheng Khng
, Sami Hietala
, Juhani Virkanen
, Suvi Lamminmäki
, Tandré Oey
, Tapio Vehmas
, Matti Nieminen
, Jaana Laatikainen-Luntama
, Marianna Kemell
, Gareth T.W. Law

^*Corresponding author for this work

University of Helsinki

Research output: Contribution to journal › Article › Scientific › peer-review

Abstract

Thermally-treated spent ion-exchange resins (OIXRs) were immobilized by mixing 1 wt% ash with a metakaolin geopolymer. Stable ¹³³Cs simulated ¹³⁷Cs. Year-long semi-dynamic leaching experiments at pH 12.5 monitored changes in pH, conductivity and dissolved ions. Na, Al, Si were rapidly released into solution and 32% of Cs leached within 28 days. Ca uptake dominated, driving Na-Ca exchange and progressive N–A–S–H to C–A–S–H transformation. XRD, FE-SEM–EDX and ²⁷Al/²⁹Si MAS-NMR showed depolymerization, Ca-rich precipitates and loss of tetrahedral Al. Despite 59% Cs loss after 1 year, results demonstrate the matrix’s long-term chemical evolution and its promise as a sustainable OIXR wasteform.

Original language	English
Pages (from-to)	7167-7177
Journal	Journal of Radioanalytical and Nuclear Chemistry
Volume	334
Issue number	10
DOIs	https://doi.org/10.1007/s10967-025-10405-7
Publication status	Published - Oct 2025
MoE publication type	A1 Journal article-refereed

Funding

This project has received funding from the Euratom research and training program 2019-2020 under grant agreement No 945098.

Keywords

Cesium immobilization
Geopolymers
Leaching behavior
Low-and intermediate-level radioactive waste
Solid-state NMR
Spent ion exchange resins

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10.1007/s10967-025-10405-7Licence: CC BY

Cite this

Vettese, G. F., Vierinen, T., Stefanini, L., Law, K. A., Khng, Y. C., Hietala, S., Virkanen, J., Lamminmäki, S., Oey, T., Vehmas, T., Nieminen, M., Laatikainen-Luntama, J., Kemell, M., & Law, G. T. W. (2025). Physicochemical evolution of a geopolymer wasteform for immobilizing thermally treated spent ion exchange resins: structural changes and cesium leachability. Journal of Radioanalytical and Nuclear Chemistry, 334(10), 7167-7177. https://doi.org/10.1007/s10967-025-10405-7

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title = "Physicochemical evolution of a geopolymer wasteform for immobilizing thermally treated spent ion exchange resins: structural changes and cesium leachability",

abstract = "Thermally-treated spent ion-exchange resins (OIXRs) were immobilized by mixing 1 wt\% ash with a metakaolin geopolymer. Stable 133Cs simulated 137Cs. Year-long semi-dynamic leaching experiments at pH 12.5 monitored changes in pH, conductivity and dissolved ions. Na, Al, Si were rapidly released into solution and 32\% of Cs leached within 28 days. Ca uptake dominated, driving Na-Ca exchange and progressive N–A–S–H to C–A–S–H transformation. XRD, FE-SEM–EDX and 27Al/29Si MAS-NMR showed depolymerization, Ca-rich precipitates and loss of tetrahedral Al. Despite 59\% Cs loss after 1 year, results demonstrate the matrix{\textquoteright}s long-term chemical evolution and its promise as a sustainable OIXR wasteform.",

keywords = "Cesium immobilization, Geopolymers, Leaching behavior, Low-and intermediate-level radioactive waste, Solid-state NMR, Spent ion exchange resins",

author = "Vettese, \{Gianni F.\} and Taavi Vierinen and Laura Stefanini and Law, \{Kathleen A.\} and Khng, \{You Cheng\} and Sami Hietala and Juhani Virkanen and Suvi Lamminm{\"a}ki and Tandr{\'e} Oey and Tapio Vehmas and Matti Nieminen and Jaana Laatikainen-Luntama and Marianna Kemell and Law, \{Gareth T.W.\}",

year = "2025",

month = oct,

doi = "10.1007/s10967-025-10405-7",

language = "English",

volume = "334",

pages = "7167--7177",

journal = "Journal of Radioanalytical and Nuclear Chemistry",

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Vettese, GF, Vierinen, T, Stefanini, L, Law, KA, Khng, YC, Hietala, S, Virkanen, J, Lamminmäki, S , Oey, T, Vehmas, T, Nieminen, M , Laatikainen-Luntama, J, Kemell, M & Law, GTW 2025, 'Physicochemical evolution of a geopolymer wasteform for immobilizing thermally treated spent ion exchange resins: structural changes and cesium leachability', Journal of Radioanalytical and Nuclear Chemistry, vol. 334, no. 10, pp. 7167-7177. https://doi.org/10.1007/s10967-025-10405-7

Physicochemical evolution of a geopolymer wasteform for immobilizing thermally treated spent ion exchange resins: structural changes and cesium leachability. / Vettese, Gianni F.; Vierinen, Taavi; Stefanini, Laura et al.
In: Journal of Radioanalytical and Nuclear Chemistry, Vol. 334, No. 10, 10.2025, p. 7167-7177.

Research output: Contribution to journal › Article › Scientific › peer-review

TY - JOUR

T1 - Physicochemical evolution of a geopolymer wasteform for immobilizing thermally treated spent ion exchange resins

T2 - structural changes and cesium leachability

AU - Vettese, Gianni F.

AU - Vierinen, Taavi

AU - Stefanini, Laura

AU - Law, Kathleen A.

AU - Khng, You Cheng

AU - Hietala, Sami

AU - Virkanen, Juhani

AU - Lamminmäki, Suvi

AU - Oey, Tandré

AU - Vehmas, Tapio

AU - Nieminen, Matti

AU - Laatikainen-Luntama, Jaana

AU - Kemell, Marianna

AU - Law, Gareth T.W.

PY - 2025/10

Y1 - 2025/10

N2 - Thermally-treated spent ion-exchange resins (OIXRs) were immobilized by mixing 1 wt% ash with a metakaolin geopolymer. Stable 133Cs simulated 137Cs. Year-long semi-dynamic leaching experiments at pH 12.5 monitored changes in pH, conductivity and dissolved ions. Na, Al, Si were rapidly released into solution and 32% of Cs leached within 28 days. Ca uptake dominated, driving Na-Ca exchange and progressive N–A–S–H to C–A–S–H transformation. XRD, FE-SEM–EDX and 27Al/29Si MAS-NMR showed depolymerization, Ca-rich precipitates and loss of tetrahedral Al. Despite 59% Cs loss after 1 year, results demonstrate the matrix’s long-term chemical evolution and its promise as a sustainable OIXR wasteform.

AB - Thermally-treated spent ion-exchange resins (OIXRs) were immobilized by mixing 1 wt% ash with a metakaolin geopolymer. Stable 133Cs simulated 137Cs. Year-long semi-dynamic leaching experiments at pH 12.5 monitored changes in pH, conductivity and dissolved ions. Na, Al, Si were rapidly released into solution and 32% of Cs leached within 28 days. Ca uptake dominated, driving Na-Ca exchange and progressive N–A–S–H to C–A–S–H transformation. XRD, FE-SEM–EDX and 27Al/29Si MAS-NMR showed depolymerization, Ca-rich precipitates and loss of tetrahedral Al. Despite 59% Cs loss after 1 year, results demonstrate the matrix’s long-term chemical evolution and its promise as a sustainable OIXR wasteform.

KW - Cesium immobilization

KW - Geopolymers

KW - Leaching behavior

KW - Low-and intermediate-level radioactive waste

KW - Solid-state NMR

KW - Spent ion exchange resins

UR - https://www.scopus.com/pages/publications/105018778403

U2 - 10.1007/s10967-025-10405-7

DO - 10.1007/s10967-025-10405-7

M3 - Article

AN - SCOPUS:105018778403

SN - 0236-5731

VL - 334

SP - 7167

EP - 7177

JO - Journal of Radioanalytical and Nuclear Chemistry

JF - Journal of Radioanalytical and Nuclear Chemistry

IS - 10

ER -

Physicochemical evolution of a geopolymer wasteform for immobilizing thermally treated spent ion exchange resins: structural changes and cesium leachability

Abstract

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Keywords

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PREDIS: PRE-DISposal management of radioactive waste

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Physicochemical evolution of a geopolymer wasteform for immobilizing thermally treated spent ion exchange resins: structural changes and cesium leachability

Abstract

Funding

Keywords

Access to Document

Other files and links

Fingerprint

Projects

PREDIS: PRE-DISposal management of radioactive waste

Cite this