Analysis of barium retention mechanisms on calcium silicate hydrate phases

Missana, Tiziana; Garcı́a-Gutiérrez, Miguel; Mingarro, M.; Alonso, Úrsula

doi:10.1016/j.cemconres.2016.12.004

Cited by 38 publications

(18 citation statements)

References 31 publications

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“…This can be explained considering that Ca 2+ is the ion determining the potential (IDP) of the C–S–H phases. 12,15…”

Section: Resultsmentioning

confidence: 99%

“…The surface properties of the C–S–H phases needed for sorption modeling were already defined in ref 15 and are summarized in Table S1 (Supporting Information); they were fixed in the model. The adsorption behavior of Na on these C–S–H phases was analyzed in a previous paper: 24 the parameters used to account for Na coadsorption are included in Table S1 and fixed as well.…”

Section: Resultsmentioning

confidence: 99%

“…The mean N 2 -Brunauer–Emmett–Teller surface area measured for C–S–H (0.8), C–S–H (1), and C–S–H (1.2) was 144 ± 40 m 2 g –1 ; the mean value measured for C–S–H (1.6) was approximately halved (73 m 2 g –1 ) due to portlandite precipitation, as previously discussed. 15…”

Section: Methodsmentioning

confidence: 99%

“…C–S–H phases may show different affinities for anions or cations, as the sign of their surface charge varies with the Ca/Si ratio. − Anion and cations can be simultaneously adsorbed on the phases to a different extent, but C–S–H with low Ca/Si ratios, presenting negative surface charge, should retain preferentially cations, whereas gels with higher Ca/Si ratios are expected to better retain anions.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2019

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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.

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“…This can be explained considering that Ca 2+ is the ion determining the potential (IDP) of the C–S–H phases. 12,15…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

et al. 2019

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“…The concentration of dissolved Ca 2+ and the variation of pH for different samples were shown in Figure 5. The modified calcium silicate hydrates can increase the concentration of dissolved Ca 2+ and pH of solution [29]. Comparing with the P-CSHs sample, the concentration of dissolved Ca…”

Section: The Analysis Of Dissolving Property For Calcium Silicatementioning

confidence: 99%

The Internal Recycle Reactor Enhances Porous Calcium Silicate Hydrates to Recover Phosphorus from Aqueous Solutions

Guan

Tian

2017

Journal of Chemistry

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In this experiment, the porous calcium silicate hydrates (P-CSHs) were prepared via a hydrothermal method and then modified by polyethylene glycol (PEG). The modified P-CSHs combined with an internal recycle reactor could successfully recover the phosphorus from electroplating wastewater. The modified P-CSHs were characterized by X-ray diffraction (XRD), N 2 adsorptiondesorption isotherms, and Fourier transform infrared spectroscopy (FT-IR). After compared with different samples, the modified P-CSHs-PEG2000 sample had larger specific surface area of 87.48 m 2 /g and higher pore volume of 0.33 cm 3 /g, indicating a high capacity for phosphorus recovery. In the process of phosphorus recovery, the pH value of solution was increased to 9.5, which would enhance the recovery efficiency of phosphorus. The dissolution rate of Ca 2+ from P-CSH-PEG2000 was fast, which was favorable for phosphorus precipitation and phosphorus recovery. The effects of initial concentration of phosphorus, P-CSHs-PEG2000 dosage, and stirring speed on phosphorus recovery were analyzed, so the optimal operation conditions for phosphorus recovery were obtained. The deposition was analyzed by XRD, N 2 adsorption-desorption, and SEM techniques; it was indicated that the pore volume and surface area of the P-CSHs-PEG2000 were significantly reduced, and the deposition on the surface of P-CSHs-PEG2000 was hydroxyapatite.

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Uptake of 226Ra in cementitious systems: A complementary solution chemistry and atomistic simulation study

Lange

Kowalski

Pšenička

et al. 2018

Applied Geochemistry

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Analysis of barium retention mechanisms on calcium silicate hydrate phases

Cited by 38 publications

References 31 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

The Internal Recycle Reactor Enhances Porous Calcium Silicate Hydrates to Recover Phosphorus from Aqueous Solutions

Uptake of 226Ra in cementitious systems: A complementary solution chemistry and atomistic simulation study

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