Modification of the Cement Matrix with Organic Additives for Stabilizing Pertechnetate Ions

Kamorny, D.A.; Safonov, Alexey; Boldyrev, Kirill; Abramova, Elena; Tyupina, E. A.; Горбунова, О. А.

doi:10.1016/j.jnucmat.2021.153295

Cited by 9 publications

(4 citation statements)

References 16 publications

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“…The reason for the 5% dos The coated CH granules (CCHG), as shown in Figure 3, were used as an additive material, and the dosage ratio was 5% of the cement weight. The reason for the 5% dosage was that the HPMC is an organic material, and organic material usually decreases the mechanical performance of cement composites [21][22][23]. Because of this negative effect, the dosage of organic additive had to be less than 5% of the cement weight [22] or water weight [21].…”

Section: Methodsmentioning

confidence: 99%

“…The reason for the 5% dosage was that the HPMC is an organic material, and organic material usually decreases the mechanical performance of cement composites [ 21 , 22 , 23 ]. Because of this negative effect, the dosage of organic additive had to be less than 5% of the cement weight [ 22 ] or water weight [ 21 ]. Therefore, a dosage ratio of 5% of the cement weight was chosen, considering both strength performance and CO 2 sequestration performance.…”

Section: Materials and Experimentsmentioning

confidence: 99%

“…was that the HPMC is an organic material, and organic material usually decreases the mechanical performance of cement composites [21][22][23]. Because of this negative effect, the dosage of organic additive had to be less than 5% of the cement weight [22] or water weight [21].…”

Section: Granulementioning

confidence: 99%

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Performance Assessment of Carbon Dioxide Sequestration in Cement Composites with a Granulation Technique

Lee,

Kim,

Min

et al. 2023

Materials

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The cement industry emits a significant amount of carbon dioxide (CO2). Therefore, the cement industry should recycle the emitted CO2. However, sequestration by carbonation in cement composites absorbs a very small amount of CO2. Therefore, a direct way of achieving this is to improve the absorption performance of CO2 in cement composites. In this study, to improve absorption, unlike in existing studies, a granulation technique was applied, and the material used was calcium hydroxide (CH). In addition, granulated CH was coated to prevent a reaction during the curing of cement paste. The coated CH granule (CCHG) was applied to 5% of the cement weight as an additive material, and the specimens were cured for 91 days to wait for the coating of CCHG to fully phase-change. The experiment of CO2 absorption showed an unexpected result, where the use of blast furnace slag (BFS) and fly ash (FA) had a negative effect on CO2 sequestration. This was because BFS and FA had a filler effect in the cement matrix, and the filler effect caused the blocking of the path of CO2. In addition, BFS and FA are well-known pozzolanic materials; the pozzolan reaction caused a reduction in the amount of CH because the pozzolan reaction consumed the CH to produce a calcium silicate hydrate. Therefore, the pozzolan reaction also had a negative effect on the CO2 sequestration performance combined with the filler effect. The CO2 sequestration efficiency was decreased between ordinary cement paste and BFS-applied specimens by 45.45%. In addition, compared to cases of ordinary cement paste and FA-applied specimens, the CO2 sequestration performance was decreased by 63.64%. Comprehensively, CO2 sequestration performance depends on the porosity and amount of CH.

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Section: Methodsmentioning

confidence: 99%

Section: Materials and Experimentsmentioning

confidence: 99%

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Performance Assessment of Carbon Dioxide Sequestration in Cement Composites with a Granulation Technique

Lee,

Kim,

Min

et al. 2023

Materials

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“…However, some works report microbial activity both on the surface of compressed bentonite and in the system of compacted bentonite with the density of 1.75 and 2 g/cm 3 , where sulfide formation indicates the activity of sulfate-reducing bacteria (SRB) was detected [25,26]. As an alternative to compaction, biocidal additives may be supplemented to the engineering mixtures, e.g., ammonium salt of O,O-dialkyl dithiohosphoric acid [27], polyhexamethyl guanidine [28][29][30], derivatives of isothiazole and brominated nitropropane dioles [31], or Amanat, Rancid, and boric acid [32].…”

Section: Introductionmentioning

confidence: 99%

Characteristics and Rates of Microbial Processes in Clays of Different Mineral and Elemental Composition in Relation to Safety Prediction for ESB Clay Materials

et al. 2022

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Microbial activity in clay barrier materials during radioactive waste disposal can lead to a violation of important physicochemical properties of the barrier system as a whole, thereby reducing the safety of the storage facility. This work evaluates the activity of the microbial complex of five bentonite and two kaolin clays. All clay materials were found to contain microorganisms, mostly with organotrophic aerobic and anaerobic metabolism capable of forming hydrogen sulfide and transforming basic and impurity clay minerals. The activity of microorganisms can increase with the ingress of degradation products of aluminophosphate matrices and cement barriers, as well as radiolysis products. For all clay the rates of microbial processes were shown to exhibit a direct correlation with the content of organic matter, kaolinite, and potassium feldspar, and an inverse correlation with montmorillonite content. A systematic methodological approach is proposed for clay materials and their susceptibility to microbial processes. The approach makes it possible, based on the content of organic matter, biophilic elements in the samples, parameters of the respiratory activity of the microbial complex, the formation of hydrogen sulfide, and other parameters, to assess in advance the possibility of using them in barriers.

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Technetium stabilization in Portland cement and bentonite clay barriers by thiourea

Safonov

Novikov

Volkov

et al. 2023

J Radioanal Nucl Chem

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Modification of the Cement Matrix with Organic Additives for Stabilizing Pertechnetate Ions

Cited by 9 publications

References 16 publications

Performance Assessment of Carbon Dioxide Sequestration in Cement Composites with a Granulation Technique

Performance Assessment of Carbon Dioxide Sequestration in Cement Composites with a Granulation Technique

Characteristics and Rates of Microbial Processes in Clays of Different Mineral and Elemental Composition in Relation to Safety Prediction for ESB Clay Materials

Technetium stabilization in Portland cement and bentonite clay barriers by thiourea

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