Radionuclide and Metal Sorption on Cement and Concrete

Mallants, Dirk; Ochs, Michael F.; Wang, Lian

doi:10.1007/978-3-319-23651-3

Cited by 63 publications

(75 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…It can be anticipated that K d ’s measured for 36 Cl in all of the C–S–H gels were null within the experimental error ( K d < 2 mL g –1 ), in agreement with previous studies. 5,7,8…”

Section: Methodsmentioning

confidence: 99%

“…Thus, despite the number of papers qualitatively describing sorption processes of (oxy)anions on cementitious materials, the mechanisms of their interactions are not yet very well established 5 and, to the best of our knowledge, literature on detailed modeling of selenite retention in C–S–H phases, including possible additional interaction effects with other adsorbing ions, especially cations, is not available.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Selenite Retention and Cation Coadsorption Effects under Alkaline Conditions Generated by Cementitious Materials: The Case of C–S–H Phases

et al. 2019

View full text Add to dashboard Cite

Contaminant migration is strongly controlled by sorption reactions; thus, the behavior of anions, which are (almost) not sorbing under alkaline conditions, is an issue of environmental concern. This is especially relevant in the frame of low and intermediate-low radioactive waste repositories, where the pH generated by cement-based materials is hyperalkaline. Selenite (SeO 3 2– ) sorption on calcium silicate hydrate (C–S–H) phases—the main cement sorbing minerals—has been investigated by batch experiments, ζ-potential measurements, and thermodynamic modeling to elucidate retention mechanisms and possible competitive/synergetic effects of cation coadsorption. Selenite sorption was shown to be nonlinear and slightly increasing with the C–S–H Ca/Si ratio; precipitation of CaSeO 3 (s) was observed for Se concentration higher than 2 × 10 –3 M. Indeed, the presence of Ca is essential to enable selenite retention under alkaline conditions. Progressive additions of Na 2 SeO 3 or NaCl salt to the phases produced a change in the C–S–H surface properties, that is, a decrease in the ζ-potential, in apparent agreement with anion adsorption. However, this effect had to be also correlated to Na coadsorption, as Cl showed null retention on the C–S–H phases. At the same time, anion adsorption had a clear effect on the retention of other cations (Ba) in the system. The distribution coefficient of Ba (at trace concentrations) suffered a moderate decrease by the presence of Na + and Cl – , but it was improved by the presence of Na + and SeO 3 2– , indicating complex competitive/synergetic effects between anions and cations. All of the experimental data were satisfactorily modeled considering a classical double-layer approach.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Selenite Retention and Cation Coadsorption Effects under Alkaline Conditions Generated by Cementitious Materials: The Case of C–S–H Phases

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Instead, Cs+ remains solvated in the aqueous phase, although its transport remains retarded [15]. Studies [16,17] focused on the hydrated cement paste and concrete compositions with silica ballast [18,19], silica fume and fly ash [20]. Jakubick et al [20] provide autoradiographic evidence of cesium concentrating on biotite, pyroxene and magnetite inclusions within the cement.…”

Section: Introductionmentioning

confidence: 99%

“…It may be, however, that the cement component of concrete is less important to adsorption if the cesium can interact with aggregate mineral surfaces at or near the surface of structural concrete. Indeed, Ochs [17] wrote to the significance of high affinity aggregate materials -"Since aggregates are the most abundant component of concrete, impurities present in nominally pure limestones, e.g. montmorillonite or illite, could contribute significantly to the sorption potential" (pg.…”

Section: Introductionmentioning

confidence: 99%

A case study of cesium sorption onto concrete materials and evaluation of wash agents: Implications for wide area recovery

Kaminski

Mertz

Jerden

et al. 2019

Journal of Environmental Chemical Engineering

View full text Add to dashboard Cite

To support the viability of a wash-down approach to mitigating nuclear contamination, this study presents a characterization of the aggregate of a common concrete by optical microscopy and the sorption-desorption characteristics of cesium from these into potential wash solutions. Various minerals with weathered surfaces displayed strong affinity for 137Cs with an effective partition coefficient Kd=120 mL/g for micas,>25-90 mL/g for feldspars, and>25-30 mL/g for amphiboles. The desorption Kd into 0.1M NH 4 Cl varied greatly but for amphiboles, sandstones, granite, and fine-grained quartzite it was>200 mL/g as a result of irreversible sorption. These same mineral phases are prevalent in all types of building materials, extending our conclusions more broadly to the problem of wide-area urban decontamination. In contrast, ionic solutions desorbed up to 98% of 137 Cs from cement, suggesting that fresh concretes with an intact surface layer of cement could be more easily decontaminated if Cs + interactions with the underlying minerals could be avoided. For practical applications common, non-hazardous chemicals such as sodium, potassium, and ammonium salts are as effective or more effective than harsher chemicals and expensive chelating agents. For example, when treated shortly after exposure, on timescales commensurate with early response phase activities, 0.5M KCl could remove nearly 50% of bound 137 Cs from concrete aggregate. Statistical analyses showed that desorption from the fine aggregate benefited from higher K + and NH 4 + concentrations. These results suggest that contamination in large areas of the urban environment can be dramatically reduced using common chemicals obtained readily from local stores.

show abstract

“…Immobilising hazardous cations like caesium-137 ( 137 Cs + , T1/2 = 30.05 a) and strontium-90 ( 90 Sr 2+ , T1/2 = 28.80 a) is key in handling RAW, especially concerning nuclear power plants [2,3], since these radionuclides are most often present in cooling water of nuclear reactors [4]. The main solidification mechanism for cationic species in OPC-based binders, which is based on precipitation of the corresponding hydroxides due to the highly alkaline pore solution, is not valid for Cs + causing a low retention and high diffusion towards the biosphere [5].…”

Section: Introductionmentioning

confidence: 99%

Incorporating Cs and Sr into blast furnace slag inorganic polymers and their effect on matrix properties

Vandevenne

Iacobescu

Pontikes

et al. 2018

Journal of Nuclear Materials

View full text Add to dashboard Cite

Minimizing harmful effects to the environment in waste-management practices requires continuous innovation. This is especially important in the field of radioactive waste management. Alternatives to the commonly used ordinary Portland cement matrices are being increasingly studied for improved immobilisation purposes. The development of inorganic polymers (IP) from industrial residues has been successfully studied for the immobilisation of caesium (Cs +) and strontium (Sr 2+). However, knowledge of the effect of these introduced elements on the IP-matrix is scarce, especially considering that studied effects are dependent on the IP-precursor characteristics and the form in which the Cs + and Sr 2+ are introduced. In this study, IPs containing varying amounts of CsNO3 and Sr(NO3)2 were developed to study the effect of the introduced elements on the IP-characteristics. IPsamples were developed from ground granulated blast furnace slag (GGBFS) and 6 M NaOH activating solution. Cs + and Sr 2+ were added to account for 0.5, 1 and 2 wt% of the total IP-mass. Throughout the entire study, Cs +-addition showed no significant effects on the studied parameters. Calorimetric results showed that Sr 2+ severely affects reaction kinetics, consuming hydroxide ions necessary for the alkali activation reaction. Sr 2+-addition also caused a severe decrease in compressive strength, increased calcium leaching, and decreased sodium and hydroxide leaching. Micro-chemical analyses showed that Cs + is almost fully incorporated in the formed IP-matrix, while Sr 2+ mainly precipitates as Sr(OH)2 in concentrated regions throughout the IP-structure. The findings presented in this paper give insights on the effect of contaminant elements on the immobilizing matrix.

show abstract

Radionuclide and Metal Sorption on Cement and Concrete

Cited by 63 publications

References 0 publications

Selenite Retention and Cation Coadsorption Effects under Alkaline Conditions Generated by Cementitious Materials: The Case of C–S–H Phases

Selenite Retention and Cation Coadsorption Effects under Alkaline Conditions Generated by Cementitious Materials: The Case of C–S–H Phases

A case study of cesium sorption onto concrete materials and evaluation of wash agents: Implications for wide area recovery

Incorporating Cs and Sr into blast furnace slag inorganic polymers and their effect on matrix properties

Contact Info

Product

Resources

About