The effect of α-isosaccharinic acid on the stability of and Th(IV) uptake by hardened cement paste

Wieland, Erich; Tits, J.; Döbler, Jens; Spieler, P.

doi:10.1524/ract.2002.90.9-11_2002.683

Cited by 28 publications

(13 citation statements)

References 13 publications

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“…Studies with Th(IV) [13][14][15][16][17][18] report strong uptake behaviour with sorption distribution ratios ( d values) typically ≥ 10 5 L kg −1 . Th(IV) uptake by cementitious materials was interpreted in terms of innersphere complexation at the surface of the C-S-H phases in cement [16,18]. Recently, an EXAFS study showed that C-S-H phases are responsible for Np(IV) retention by hardened cement paste (HCP) and that Np(IV) is predominantly incorporated in the interlayer of C-S-H phases [19].…”

Section: Introductionmentioning

confidence: 99%

Influence of the redox state on the neptunium sorption under alkaline conditions: Batch sorption studies on titanium dioxide and calcium silicate hydrates

Tits¹,

Laube²,

Wieland

et al. 2014

Radiochimica Acta

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Influence of the redox state on the neptunium sorption under alkaline conditions: Batch sorption studies on titanium dioxide and calcium silicate hydrates Abstract: Wet chemistry experiments were carried out to investigate the effect of the redox state and aqueous speciation on the uptake of neptunium by titanium dioxide (TiO 2 ) and by calcium silicate hydrates (C-S-H) under alkaline conditions. TiO 2 was chosen as a reference sorbent to determine the surface complexation behaviour of neptunium under alkaline conditions. C-S-H phases are important constituents of cement and concrete. They may contribute significantly to radionuclide retention due to their high recrystallization rates making incorporation the dominating sorption mechanism for many radionuclides (e.g. the actinides) on these materials. The sorption of neptunium on both solids was found to depend strongly on the degree of hydrolysis. On TiO In addition to the effect of hydrolysis, the presence of Ca is found to promote Np(V) and Np(VI) sorption on TiO 2 whereas on C-S-H phases, the present wet chemistry data do not give unambiguous evidence. Thus, the aqueous speciation appears to have a similar influence on the sorption of the actinides on both types of solids despite the different sorption mechanism.The similar d values for Np(IV,V,VI) sorption at pH = 10 can be explained qualitatively by invoking inter-ligand electrostatic repulsion between OH groups in the coordination sphere of Np(V) and Np(VI). This mechanism was proposed earlier in the literature for the prediction of actinide complexation constants with inorganic ligands. A limiting coordination number for each Np redox state, resulting from the inter-ligand electrostatic repulsion, allows the weaker sorption of the highest hydrolysed Np(V,VI) species to be explained.

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Section: Introductionmentioning

confidence: 99%

Influence of the redox state on the neptunium sorption under alkaline conditions: Batch sorption studies on titanium dioxide and calcium silicate hydrates

Tits¹,

Laube²,

Wieland

et al. 2014

Radiochimica Acta

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“…They also could be sorbed onto the HCP surface with a competing effect on anionic RN uptake. The influence of organics such as isosaccharinic acid (ISA), the most important degradation product of cellulose, on the behaviour of cationic fission products and actinides has already been studied in cementitious solution and materials [6][7][8][9][10][11]. The sorption of ISA on undegraded HCP surface has already been observed and measured [12], and its competing effect on anionic species sorption onto HCP has already been observed [13].…”

Section: Introductionmentioning

confidence: 99%

Uptake of anionic radionuclides onto degraded cement pastes and competing effect of organic ligands

Pointeau¹,

Coreau²,

Reiller³

2008

Radiochimica Acta

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To cite this version:I. Pointeau, N. Coreau, Pascal E. Reiller. Uptake of anionic radionuclides onto degraded cement pastes and competing effect of organic ligands. Radiochimica Acta, R Oldenbourg Verlag GMBH, 2008, 96 (6) .0), corresponding to the decalcification of the calcium silicate hydrate (C-S-H) phases. The behaviour of anionic RN seems to be correlated to the evolution of calcium concentration and is opposed to the evolution of sulphate concentration in solution which could have a competing effect. Comparison is done with the behaviour of caesium and uranium(VI), which is a cationic RN but has a major negative hydrolysed species at high pH. As awaited, the uranium(VI) behaviour is very different from purely anionic RN one in accord with spectroscopic analyses from literature works. The R d values have also been measured for the organic ligands isosaccharinate (ISA) and EDTA. The uptake of ISA can be important and competing effect with the sorption of SeO 3 2− has been evidenced in HCP suspensions as a function of the ISA concentration.

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“…Isosaccharinic acid (ISA) was found to be the main degradation product [29]. ISA forms stable complexes, especially with tri-and tetravalent nuclides and can significantly influence the sorption of radionuclides [30][31][32]. The extent of the effect, however, depends on the ISA concentration in solution.…”

Section: Influence Of Organics and Colloidsmentioning

confidence: 99%

“…The aqueous ISA concentration was estimated to be below ~ 3.10 -7 M based on realistic assumptions concerning the cellulose inventory, the degree of degradation and the extent of sorption under repository conditions [4]. Note that no effect of ISA on the uptake of the safety-relevant radionuclides by HCP has been observed experimentally at this concentration level [30,32,34].…”

Section: Influence Of Organics and Colloidsmentioning

confidence: 99%

Development of a sorption data base for the cementitious near-field of a repository for radioactive waste

2003

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The migration of radionuclides within a repository for radioactive waste is retarded due to interaction with the engineered barrier system. Sorption processes play a decisive role in the retardation of radionuclides in the repository environment, and thus, the development of sorption data bases (SDBs) is an important task and an integral part of performance assessment. The methodology applied in the development of a SDB for the cementitious near-field of a repository for long-lived intermediate-level waste is presented in this study. The development of such a SDB requires knowledge of the chemical conditions of the near-field and information on the uptake process of radionuclides by hardened cement paste. The principles upon which the selection of the "best available" laboratory sorption values is based are outlined. The influence of cellulose degradation products, cement additives and cement-derived colloids on the sorption behaviour of radionuclides is addressed in conjunction with the development of the SDB.

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The effect of α-isosaccharinic acid on the stability of and Th(IV) uptake by hardened cement paste

Abstract: Hardened cement paste / Stability / Thorium / Sorption / Isosaccharinic acid

Cited by 28 publications

References 13 publications

Influence of the redox state on the neptunium sorption under alkaline conditions: Batch sorption studies on titanium dioxide and calcium silicate hydrates

Influence of the redox state on the neptunium sorption under alkaline conditions: Batch sorption studies on titanium dioxide and calcium silicate hydrates

Uptake of anionic radionuclides onto degraded cement pastes and competing effect of organic ligands

Development of a sorption data base for the cementitious near-field of a repository for radioactive waste

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