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Ellina Bernard - One of the best experts on this subject based on the ideXlab platform.
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aluminum incorporation into Magnesium Silicate hydrate m s h
Cement and Concrete Research, 2020Co-Authors: Ellina Bernard, Barbara Lothenbach, Isabelle Pochard, Celine Cauditcoumes, Daniel RentschAbstract:Abstract The incorporation of aluminum in Magnesium Silicate hydrate (M-S-H) phases was investigated. Magnesium (alumino) Silicate hydrate (M-(A-)S-H) with Mg/Si ratios equal to 1.1 or 1.7 and Al/Si ranging from 0 to 0.2 were synthetized in batch experiments and equilibrated at 20, 50 and 70 °C. pH values between 9 and 10.5 were observed and aluminum up to Al/Si ~0.15–0.18 was incorporated in M-(A-)S-H. Thermogravimetric analysis (TGA), X-ray diffraction (XRD), X-ray pair distribution function (PDF) analysis, transmission electron microscopy (TEM), 29Si and 27Al MAS NMR data showed that the M-(A-)S-H phases formed were similar to M-S-H with limited coherent size and a comparable polymerization degree of the tetrahedral Silicates. Aluminum was incorporated in both tetrahedral and octahedral sites of M-S-H, while no aluminum was present as exchangeable cation on the surface sites.
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alkali binding by Magnesium Silicate hydrates
Journal of the American Ceramic Society, 2019Co-Authors: Ellina Bernard, Barbara Lothenbach, Isabelle Pochard, Celine CauditcoumesAbstract:The binding of Na+, K+, and Li+ by Magnesium Silicate hydrate (M–S–H) was investigated in batch sorption experiments. Sorption isotherms and cation exchange measurements indicated the binding of alkalis in cation exchange sites compensating the negative surface charge of M–S–H. Higher pH values led to further deprotonation of the silanol groups and a higher alkali uptake by M–S–H. No significant incorporation of alkalis in the main silica or Magnesium oxide sheets was observed. However, the silica sheets were less polymerized in the presence of higher alkali hydroxide concentrations.
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characterization of Magnesium Silicate hydrate m s h
Cement and Concrete Research, 2019Co-Authors: Ellina Bernard, Barbara Lothenbach, Isabelle Pochard, Christophe Chlique, Mateusz Wyrzykowski, Alexandre Dauzeres, Celine CauditcoumesAbstract:Abstract In this study, the structure of synthetic Magnesium Silicate hydrated phases (M-S-H) and the distribution of water as a function of the Mg/Si ratio were investigated. Different analytical techniques indicated that M-S-H phases are nano-crystallite hydrated phylloSilicates with relatively short coherence length (1.2 nm) and small particle size (>200 m2/g). Zeta potential and cations exchange capacity measurements showed a negative surface charge on M-S-H from the deprotonation of the silanol groups. The negative surface charge is compensated by exchangeable Magnesium or others cations. Combined analyses were used to characterize the water distribution in M-S-H revealing the following: i) confined water; its amount depends mainly on the relative humidity ii) very confined water (or possibly water coordinated to Magnesium), and iii) hydroxyl groups bound to Magnesium and to silicon.
Barbara Lothenbach - One of the best experts on this subject based on the ideXlab platform.
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aluminum incorporation into Magnesium Silicate hydrate m s h
Cement and Concrete Research, 2020Co-Authors: Ellina Bernard, Barbara Lothenbach, Isabelle Pochard, Celine Cauditcoumes, Daniel RentschAbstract:Abstract The incorporation of aluminum in Magnesium Silicate hydrate (M-S-H) phases was investigated. Magnesium (alumino) Silicate hydrate (M-(A-)S-H) with Mg/Si ratios equal to 1.1 or 1.7 and Al/Si ranging from 0 to 0.2 were synthetized in batch experiments and equilibrated at 20, 50 and 70 °C. pH values between 9 and 10.5 were observed and aluminum up to Al/Si ~0.15–0.18 was incorporated in M-(A-)S-H. Thermogravimetric analysis (TGA), X-ray diffraction (XRD), X-ray pair distribution function (PDF) analysis, transmission electron microscopy (TEM), 29Si and 27Al MAS NMR data showed that the M-(A-)S-H phases formed were similar to M-S-H with limited coherent size and a comparable polymerization degree of the tetrahedral Silicates. Aluminum was incorporated in both tetrahedral and octahedral sites of M-S-H, while no aluminum was present as exchangeable cation on the surface sites.
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alkali binding by Magnesium Silicate hydrates
Journal of the American Ceramic Society, 2019Co-Authors: Ellina Bernard, Barbara Lothenbach, Isabelle Pochard, Celine CauditcoumesAbstract:The binding of Na+, K+, and Li+ by Magnesium Silicate hydrate (M–S–H) was investigated in batch sorption experiments. Sorption isotherms and cation exchange measurements indicated the binding of alkalis in cation exchange sites compensating the negative surface charge of M–S–H. Higher pH values led to further deprotonation of the silanol groups and a higher alkali uptake by M–S–H. No significant incorporation of alkalis in the main silica or Magnesium oxide sheets was observed. However, the silica sheets were less polymerized in the presence of higher alkali hydroxide concentrations.
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characterization of Magnesium Silicate hydrate m s h
Cement and Concrete Research, 2019Co-Authors: Ellina Bernard, Barbara Lothenbach, Isabelle Pochard, Christophe Chlique, Mateusz Wyrzykowski, Alexandre Dauzeres, Celine CauditcoumesAbstract:Abstract In this study, the structure of synthetic Magnesium Silicate hydrated phases (M-S-H) and the distribution of water as a function of the Mg/Si ratio were investigated. Different analytical techniques indicated that M-S-H phases are nano-crystallite hydrated phylloSilicates with relatively short coherence length (1.2 nm) and small particle size (>200 m2/g). Zeta potential and cations exchange capacity measurements showed a negative surface charge on M-S-H from the deprotonation of the silanol groups. The negative surface charge is compensated by exchangeable Magnesium or others cations. Combined analyses were used to characterize the water distribution in M-S-H revealing the following: i) confined water; its amount depends mainly on the relative humidity ii) very confined water (or possibly water coordinated to Magnesium), and iii) hydroxyl groups bound to Magnesium and to silicon.
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properties of Magnesium Silicate hydrates m s h
Cement and Concrete Research, 2016Co-Authors: Dominik Nied, Kasper Enemarkrasmussen, E Lhopital, Jorgen Skibsted, Barbara LothenbachAbstract:Abstract Investigations of synthetic Magnesium Silicate hydrate (M-S-H) samples have shown that M-S-H aged for 1 year can exhibit variable compositions with molar Mg/Si ratios in the range 0.7 ≤ Mg/Si ≤ 1.5. At lower Mg/Si ratio, additional silica is present whereas brucite is observed for Mg/Si ≥ 1.3. FT-IR and 29 Si NMR data reveal a high degree of Silicate polymerisation, indicating the formation of Silicate sheets. TGA shows the presence of bound water and of hydroxyl groups bound to Mg and as silanol groups in the M-S-H, in accord with 29 Si{ 1 H}CP/MAS and high-speed 1 H NMR measurements. Raman and XRD data suggest that the M-S-H structure is related to a disordered talc precursor at low Mg/Si and to a serpentine precursor at high Mg/Si ratio. Solubility products for M-S-H phases were calculated on basis of the compositions of the aqueous solutions and a solid solution model was suggested.
Guozhong Wang - One of the best experts on this subject based on the ideXlab platform.
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microwave assisted synthesis of magnetic fe3o4 mesoporous Magnesium Silicate core shell composites for the removal of heavy metal ions
Microporous and Mesoporous Materials, 2017Co-Authors: Zhengfu Zhao, Xian Zhang, Hongjian Zhou, Mingguang Kong, Guozhong WangAbstract:Abstract An ultrafast and facile microwave assisted hydrothermal approach was applied to synthesize magnetic Fe 3 O 4 -mesoporous Magnesium Silicate (FMMS) core-shell composites for effective removal of Cu 2+ , Cd 2+ and Pb 2+ from aqueous solutions. The FMMS composites have mesoporous Magnesium Silicate shells encapsulated Fe 3 O 4 spheres core structures, and the mesoporous shell assembled by a large number of intercrossed nanosheets with a diameter of 4.0 nm pores, thus exhibited the excellent capability to remove Pb 2+ (223.2 mg/g) and Cu 2+ (53.5 mg/g) ions from aqueous solutions. The superior removal capacity of the FMMS composites can be ascribed to its mesoporous structures with abundant adsorption active sites. The competitive adsorption studies showed that the adsorbent affinity order of three metal ions by FMMS composites is Cu 2+ >Pb 2+ >Cd 2+ . It is noteworthy that the heavy metal ions could not only adsorb on the surface of FMMS composites, but also intercalate into the intercrossed nanosheets of mesoporous Magnesium Silicate shell, which reveals the synergistic effect of the electrostatic attraction, surface complexation and ion exchange coupled with the adsorption bonding with surface hydroxyl groups. Furthermore, the FMMS composites exhibited excellent sorption-regeneration performance, which can be easily separated and recovered by external magnet. All results demonstrated that the magnetic FMMS core-shell composite was a promising sorbent material for the preconcentration and separation of heavy metal ions from the waste water.
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chemical template synthesis of micro nanoscale Magnesium Silicate hollow spheres for waste water treatment
Chemistry: A European Journal, 2010Co-Authors: Yongqiang Wang, Guozhong Wang, Hongqiang Wang, Changhao Liang, Lide ZhangAbstract:Micro/nanoscale Magnesium Silicate hollow spheres were synthesized by using silica colloidal spheres as a chemical template in one pot. The hollow spherical structure, consisting of well-separated nanoscale units, was microscale as a whole and could be easily handled in solution. The as-synthesized Magnesium Silicate hollow spheres with large specific surface area showed availability for the removal of organic and heavy-metal ions efficiently from waste water. Importantly, the micro/nanoscale Magnesium Silicate hollow spheres that had adsorbed organic pollutants could be regenerated by calcination and used repeatedly in pollutant removal. Magnesium Silicate hollow spheres synthesized by a scaled-up chemical template method may have potential applications in removing cationic dyes and heavy-metal ions from waste water.
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Chemical‐Template Synthesis of Micro/Nanoscale Magnesium Silicate Hollow Spheres for Waste‐Water Treatment
Chemistry: A European Journal, 2010Co-Authors: Yongqiang Wang, Guozhong Wang, Hongqiang Wang, Changhao Liang, Lide ZhangAbstract:Micro/nanoscale Magnesium Silicate hollow spheres were synthesized by using silica colloidal spheres as a chemical template in one pot. The hollow spherical structure, consisting of well-separated nanoscale units, was microscale as a whole and could be easily handled in solution. The as-synthesized Magnesium Silicate hollow spheres with large specific surface area showed availability for the removal of organic and heavy-metal ions efficiently from waste water. Importantly, the micro/nanoscale Magnesium Silicate hollow spheres that had adsorbed organic pollutants could be regenerated by calcination and used repeatedly in pollutant removal. Magnesium Silicate hollow spheres synthesized by a scaled-up chemical template method may have potential applications in removing cationic dyes and heavy-metal ions from waste water.
Lide Zhang - One of the best experts on this subject based on the ideXlab platform.
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chemical template synthesis of micro nanoscale Magnesium Silicate hollow spheres for waste water treatment
Chemistry: A European Journal, 2010Co-Authors: Yongqiang Wang, Guozhong Wang, Hongqiang Wang, Changhao Liang, Lide ZhangAbstract:Micro/nanoscale Magnesium Silicate hollow spheres were synthesized by using silica colloidal spheres as a chemical template in one pot. The hollow spherical structure, consisting of well-separated nanoscale units, was microscale as a whole and could be easily handled in solution. The as-synthesized Magnesium Silicate hollow spheres with large specific surface area showed availability for the removal of organic and heavy-metal ions efficiently from waste water. Importantly, the micro/nanoscale Magnesium Silicate hollow spheres that had adsorbed organic pollutants could be regenerated by calcination and used repeatedly in pollutant removal. Magnesium Silicate hollow spheres synthesized by a scaled-up chemical template method may have potential applications in removing cationic dyes and heavy-metal ions from waste water.
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Chemical‐Template Synthesis of Micro/Nanoscale Magnesium Silicate Hollow Spheres for Waste‐Water Treatment
Chemistry: A European Journal, 2010Co-Authors: Yongqiang Wang, Guozhong Wang, Hongqiang Wang, Changhao Liang, Lide ZhangAbstract:Micro/nanoscale Magnesium Silicate hollow spheres were synthesized by using silica colloidal spheres as a chemical template in one pot. The hollow spherical structure, consisting of well-separated nanoscale units, was microscale as a whole and could be easily handled in solution. The as-synthesized Magnesium Silicate hollow spheres with large specific surface area showed availability for the removal of organic and heavy-metal ions efficiently from waste water. Importantly, the micro/nanoscale Magnesium Silicate hollow spheres that had adsorbed organic pollutants could be regenerated by calcination and used repeatedly in pollutant removal. Magnesium Silicate hollow spheres synthesized by a scaled-up chemical template method may have potential applications in removing cationic dyes and heavy-metal ions from waste water.
Celine Cauditcoumes - One of the best experts on this subject based on the ideXlab platform.
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aluminum incorporation into Magnesium Silicate hydrate m s h
Cement and Concrete Research, 2020Co-Authors: Ellina Bernard, Barbara Lothenbach, Isabelle Pochard, Celine Cauditcoumes, Daniel RentschAbstract:Abstract The incorporation of aluminum in Magnesium Silicate hydrate (M-S-H) phases was investigated. Magnesium (alumino) Silicate hydrate (M-(A-)S-H) with Mg/Si ratios equal to 1.1 or 1.7 and Al/Si ranging from 0 to 0.2 were synthetized in batch experiments and equilibrated at 20, 50 and 70 °C. pH values between 9 and 10.5 were observed and aluminum up to Al/Si ~0.15–0.18 was incorporated in M-(A-)S-H. Thermogravimetric analysis (TGA), X-ray diffraction (XRD), X-ray pair distribution function (PDF) analysis, transmission electron microscopy (TEM), 29Si and 27Al MAS NMR data showed that the M-(A-)S-H phases formed were similar to M-S-H with limited coherent size and a comparable polymerization degree of the tetrahedral Silicates. Aluminum was incorporated in both tetrahedral and octahedral sites of M-S-H, while no aluminum was present as exchangeable cation on the surface sites.
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alkali binding by Magnesium Silicate hydrates
Journal of the American Ceramic Society, 2019Co-Authors: Ellina Bernard, Barbara Lothenbach, Isabelle Pochard, Celine CauditcoumesAbstract:The binding of Na+, K+, and Li+ by Magnesium Silicate hydrate (M–S–H) was investigated in batch sorption experiments. Sorption isotherms and cation exchange measurements indicated the binding of alkalis in cation exchange sites compensating the negative surface charge of M–S–H. Higher pH values led to further deprotonation of the silanol groups and a higher alkali uptake by M–S–H. No significant incorporation of alkalis in the main silica or Magnesium oxide sheets was observed. However, the silica sheets were less polymerized in the presence of higher alkali hydroxide concentrations.
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characterization of Magnesium Silicate hydrate m s h
Cement and Concrete Research, 2019Co-Authors: Ellina Bernard, Barbara Lothenbach, Isabelle Pochard, Christophe Chlique, Mateusz Wyrzykowski, Alexandre Dauzeres, Celine CauditcoumesAbstract:Abstract In this study, the structure of synthetic Magnesium Silicate hydrated phases (M-S-H) and the distribution of water as a function of the Mg/Si ratio were investigated. Different analytical techniques indicated that M-S-H phases are nano-crystallite hydrated phylloSilicates with relatively short coherence length (1.2 nm) and small particle size (>200 m2/g). Zeta potential and cations exchange capacity measurements showed a negative surface charge on M-S-H from the deprotonation of the silanol groups. The negative surface charge is compensated by exchangeable Magnesium or others cations. Combined analyses were used to characterize the water distribution in M-S-H revealing the following: i) confined water; its amount depends mainly on the relative humidity ii) very confined water (or possibly water coordinated to Magnesium), and iii) hydroxyl groups bound to Magnesium and to silicon.
