XPS, 29Si, 27Al, 11B MAS -NMR, ATR-IR and FESEM characterization of geopolymer based on borax modified water glass activated Fly ash-GGBS blend

Revathi, T.; Jeyalakshmi, R.

doi:10.1088/2053-1591/ab255e

Cited by 29 publications

(6 citation statements)

References 48 publications

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“…The results from the current study further show that borax can reduce yield stress and plastic viscosity. Furthermore, borax has no negative effect on the strength of AAC mixtures; in fact, it slightly improves the compressive strength [ 41 , 42 , 43 ]. This is of high importance, as the admixture technology in AAC is still in its early stages.…”

Section: Resultsmentioning

confidence: 99%

Rheology of Alkali-Activated Blended Binder Mixtures

2021

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Alkali-activated cement (AAC) is an alternative cement that has been increasingly studied over the past decades mainly because of its environmental benefits. However, most studies are on heat-cured AACs and are focused on mechanical properties. There is a lack of research on the fresh properties of ambient-cured AAC systems. This study investigates the rheological properties of ambient-temperature-cured alkali-activated blended binder mixtures activated with sodium silicate and sodium hydroxide solutions. The influence of binder amount, alkaline solid to binder ratio (AS/B), sodium silicate to sodium hydroxide solids ratio (SS/SH), and total water content to total solid (from the binding materials) ratio (TW/TS) on the rheological properties are investigated. The effect of borax as an admixture and silica fume as a replacement for fly ash is also investigated. The results showed that both the yield stress and plastic viscosity are mainly affected by the binder content and TW/TS ratio decreasing with the increase of each parameter. The yield stress increased with the increase of the SS/SH ratio. Borax significantly reduced the yield stress, while silica fume’s effect was dependent on its dosage.

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Section: Resultsmentioning

confidence: 99%

Rheology of Alkali-Activated Blended Binder Mixtures

2021

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“…Figure exhibits the XPS survey spectrum and corresponding high revolution spectra of YMAS:0.01Eu 2+ ,0.01Ce 3+ , which further indicates the presence of Y, Mg, Al, Si, Eu, Ce, and O. Thereinto, the two peaks at 159.5 and 157.8 eV are attributed to Y 3d 3/2 and Y 3d 5/2 , respectively . The binding energies at 50.1, 74.2, and 102.1 eV are related to Mg 2p, Al 2p, and Si 2p, respectively. , The Eu 3d spectra are composed of two peaks at 1158.3 and 1123.9 eV, ascribed to Eu 3d 3/2 and Eu 3d 5/2 of Eu 2+ , respectively . The binding energies at 906.8 and 885.5 eV are attributed to Ce 3d 3/2 and Ce 3d 5/2 , respectively .…”

Section: Resultsmentioning

confidence: 85%

“…39 The binding energies at 50.1, 74.2, and 102.1 eV are related to Mg 2p, Al 2p, and Si 2p, respectively. 40,41 The Eu 3d spectra are composed of two peaks at 1158.3 and 1123.9 eV, ascribed to Eu 3d 3/2 and Eu 3d 5/2 of Eu 2+ , respectively. 42 The binding energies at 906.8 and 885.5 eV are attributed to Ce 3d 3/2 and Ce 3d 5/2 , respectively.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Luminescence and Energy Transfer of Color-Tunable Y₂Mg₂Al₂Si₂O₁₂:Eu²⁺,Ce³⁺ Phosphors

Zhang

Zheng

et al. 2021

Inorg. Chem.

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Color-tunable phosphors can be obtained through codoping strategies and energy transfer regulation. Ce 3+ and Eu 2+ are the most common and effective activator ions used in phosphor materials. However, the energy transfer from Eu 2+ to Ce 3+ is rarely reported. In this work, Y 2 Mg 2 Al 2 Si 2 O 12 (YMAS):Eu 2+ ,Ce 3+ phosphors were successfully synthesized, which was confirmed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Rietveld refinement, scanning electron microscopy (SEM) and element mapping images, and spectral information. The luminescent color of YMAS:Eu 2+ ,Ce 3+ phosphors could be tuned from blue to cyan to light green to yellow-green and finally to green-yellow, which was achieved by adjusting the energy transfer between different dopants. The energy transfer from Eu 2+ to Ce 3+ was confirmed by photoluminescence spectra and fluorescence decay curves. Within the experimental gradient, the energy transfer efficiency could reach up to 48%. At 373 K, the Y 1.99 Mg 1.99 Al 2 Si 2 O 12 :0.01Eu 2+ ,0.01Ce 3+ (YMAS:0.01Eu 2+ ,0.01Ce 3+ ) phosphor exhibited a total integral emission loss of only 8%, and the emission peak intensity decreased to 95%, indicating the excellent thermal stability. The white light-emitting diode (WLED) fabricated by the YMAS:0.01Eu 2+ ,0.01Ce 3+ phosphor has the same level correlated color temperature (CCT = 5841 K), greatly improved color rendering index (R a = 87.8), and higher quality white light color (CIE = (0.3258, 0.3214)) than the WLED made by the YMAS:0.01Eu 2+ phosphor, indicating that the performance of the phosphor was significantly improved by introducing Ce 3+ . This work provides an effective guide for the design and development of highly efficient color-tunable phosphors involving energy transfer from Eu 2+ to Ce 3+ in some specific materials, such as garnet structures.

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“…The intensification of O, Si, and Al peaks occurs mainly due to the geopolymerization of aluminosilicate. There are three types of primary chemical states of oxygen in geopolymer including Si-O-Al, Si-O-Si and Si-O-H, with the main spectral line positions at 531, 532 and 533 eV, according to the literature [ 57 , 58 , 59 ]. The fitted parameters of the O1 s XPS spectra are shown in Figure 4 , Figure 5 and Figure 6 b for GPNd and GPSm, respectively.…”

Section: Resultsmentioning

confidence: 99%

Structural and Chemical Properties of Geopolymer Gels Incorporated with Neodymium and Samarium

Nenadović

Kljajević

Ivanović

et al. 2021

Gels

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The present work was focused on doping of 1% and 5% both of Nd2O3 and Sm2O3 in geopolymer gels. One of the main goals was to determine the influence of the behavior of Nd and Sm as dopants and structural nanoparticles changes of the final geopolymer formed. It is shown that the disorder formed by alkali activation of metakaolin can accommodate the rare earth cations Nd3+ and Sm3+ into their aluminosilicate framework structure. The main geopolymerization product identified in gels is Al-rich (Na)-AS-H gel comprising Al and Si in tetrahedral coordination. Na+ ions were balancing the negative charge resulting from Al3+ in tetrahedral coordination. The changes in the structures of the final product (geopolymer/Nd2O3; Sm2O3), has been characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) analysis with energy dispersive spectrometry (EDS). Nucleation at the seed surfaces leads to the formation of phase-separated gels from rare earth phase early in the reaction process. It is confirmed that Nd and Sm have been shown to form unstable hydroxides Nd(OH)3 and Sm(OH)3 that are in equilibrium with the corresponding oxides.

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XPS, ²⁹Si, ²⁷Al, ¹¹B MAS -NMR, ATR-IR and FESEM characterization of geopolymer based on borax modified water glass activated Fly ash-GGBS blend

Cited by 29 publications

References 48 publications

Rheology of Alkali-Activated Blended Binder Mixtures

Rheology of Alkali-Activated Blended Binder Mixtures

Luminescence and Energy Transfer of Color-Tunable Y₂Mg₂Al₂Si₂O₁₂:Eu²⁺,Ce³⁺ Phosphors

Structural and Chemical Properties of Geopolymer Gels Incorporated with Neodymium and Samarium

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XPS, 29Si, 27Al, 11B MAS -NMR, ATR-IR and FESEM characterization of geopolymer based on borax modified water glass activated Fly ash-GGBS blend

Cited by 29 publications

References 48 publications

Rheology of Alkali-Activated Blended Binder Mixtures

Rheology of Alkali-Activated Blended Binder Mixtures

Luminescence and Energy Transfer of Color-Tunable Y2Mg2Al2Si2O12:Eu2+,Ce3+ Phosphors

Structural and Chemical Properties of Geopolymer Gels Incorporated with Neodymium and Samarium

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XPS, ²⁹Si, ²⁷Al, ¹¹B MAS -NMR, ATR-IR and FESEM characterization of geopolymer based on borax modified water glass activated Fly ash-GGBS blend

Luminescence and Energy Transfer of Color-Tunable Y₂Mg₂Al₂Si₂O₁₂:Eu²⁺,Ce³⁺ Phosphors