Solid-state aluminium-27 nuclear magnetic resonance chemical shift and quadrupole coupling data for condensed AlO<sub>4</sub>tetrahedra

Müller, D.; Geßner, W.; Samoson, Ago; Lippmaa, É.; Scheler, G.

doi:10.1039/dt9860001277

Cited by 105 publications

(54 citation statements)

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“…The broad peak at 30-32 ppm assigned to AlO 5 begins to decline in relative intensity beyond 925 ºC and its elimination appears to be the only significant change in the nature or distribution of 27 Al NMR signals that coincide with the second DSC exotherm at 1020 ºC. The broad strong peak centred at 63 ppm can be assigned to a range of AlO 4 environments that are bonded through neighbouring AlO 6 structural units (Müller et al, 1986). The interpretation is consistent with the presence of the transition alumina phases such as θ-Al 2 O 3 and potentially -Al 2 O 3 in which aluminium is distributed equally between octahedral and tetrahedral sites.…”

Section: Thermal and Structural Transformations Of Phosphoric Acid Mementioning

confidence: 98%

“…This is characteristic of AlO 4 environments bonded through AlO 6 structural units (Müller et al 1986) as found in the ccp -alumina phase. No differences were found between the NMR spectra of the samples heated at 900 °C and 1000 °C (containing -alumina) and that of the 1100 °C sample, shown by XRD to contain principally -alumina.…”

Section: Thermal and Structural Transformations Of Sulphuric Acid Memmentioning

confidence: 99%

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Fabrication, Structure and Properties of Nanostructured Ceramic Membranes

Brown¹,

Wu²,

Smith³

2012

Ceramic Materials - Progress in Modern Ceramics

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Section: Thermal and Structural Transformations Of Phosphoric Acid Mementioning

confidence: 98%

Section: Thermal and Structural Transformations Of Sulphuric Acid Memmentioning

confidence: 99%

Fabrication, Structure and Properties of Nanostructured Ceramic Membranes

Brown¹,

Wu²,

Smith³

2012

Ceramic Materials - Progress in Modern Ceramics

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“…The increase in intensity of the Raman vibrational band corresponding to AlO 6 units at 500 cm À1 and the change in chemical shi of the 27 Al MAS-NMR spectra for the Al(OP) 6 units (Table 3), further suggests that the ionic character between Al and O might be decreased through the decrease of the average Al-O bond length in the Al(OP) 6 unit. 31,61 This indicates the rearrangement of Q 0 (3Al) and Q 0 (2Al) units with the addition of boron. This activity could be explained based on the formation of borate and borophosphate domains in NCABP glass.…”

Section: 65mentioning

confidence: 99%

“…Therefore, the peaks appeared aer the deconvolution are assigned to the following structural units: the peak at around 60 ppm is attributed to the AlO 4 tetrahedra connected to the AlO 6 octahedra units, the peak at around 50 ppm is assigned to Al(OP) 4 units, the peak at around 26 ppm is assigned to Al(OP) 5 units, the peak at around 16 ppm is allocated to Al(OAl) 6 units, and the peak at around À2.5 ppm is attributed to Al(OP) 6 units. 61 Nevertheless, the deconvolution peaks obtained from the 27 Al MAS-NMR spectra for NCAGP glass appeared in the more deshielded region compared to that of NCAP glass. This shi was attributed to the effect of partial substitution of Ga for Al in AlO 6 sites, which are attached to the AlO 4 tetrahedron, and Ga for P in PO 4 units, which were connected in Al(OP) 5 and Al(OP) 6 units.…”

mentioning

confidence: 99%

Structural elucidation of NASICON (Na₃Al₂P₃O₁₂) based glass electrolyte materials: effective influence of boron and gallium

et al. 2018

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Understanding the conductivity variations induced by compositional changes in sodium super ionic conducting (NASICON) glass materials is highly relevant for applications such as solid electrolytes for sodium (Na) ion batteries. In the research reported in this paper, NASICON-based NCAP glass (Na 2.8 Ca 0.1 Al 2 P 3 O 12 ) was selected as the parent glass. The present study demonstrates the changes in the Ga nuclei) were used. The Raman spectrum revealed that the NCAP glass structure is more analogous to the AlPO 4 mesoporous glass structure. The Ga MAS-NMR spectrum suggests that gallium cations in the NCAGP glass compete with the alumina cations and occupy four (GaO 4 ), five (GaO 5 ) and six (GaO 6 ) coordinated sites. The Raman spectrum of NCAGP glass indicates that sodium cations have also been substituted by gallium cations in the NCAP glass structure. From impedance analysis, the dc conductivity of the NCAP glass ($3.13 Â 10 À8 S cm À1) is slightly decreased with the substitution of gallium ($2.27 Â 10 À8 S cm À1) but considerably decreased with the substitution of boron ($1.46 Â 10 À8 S cm À1 ). The variation in the conductivity values are described based on the structural changes of NCAP glass with the substitution of gallium and boron.

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“…High-resolution solid-state MAS NMR has recently become an important tool for providing specific chemical and structural information of a type that has been unattainable by more traditional means (7)(8)(9)(10)(11)(12)(13). X-ray diffraction (XRD) analysis is one of the traditional methods and is used to determine the crystalline nature of solid materials.…”

mentioning

confidence: 99%

Investigations of aluminum hydroxyphosphates and activated sludge by ²⁷Al and ³¹P MAS NMR

Duffy¹,

vanLoon²

1995

Can. J. Chem.

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High-resolution solid-state 2 7~1 and 3 1~ MAS NMR has been used to investigate the nature of aluminum-and phosphorus-containing solids formed during wastewater treatment. Although difficult to characterize by conventional techniques, these amorphous solids can be characterized by MAS NMR, providing information about their short-range ordering. In the present study, most of the solids were precipitated under conditions of high alkalinity, similar to those encountered during wastewater treatment. The ageing time of the aluminum hydroxide prior to the addition of phosphate (t,), the ageing time of the aluminum hydroxyphosphates after the addition of phosphate (t2), and the phosphorus to aluminum molar ratio were controlled while the effects of changing the parameters were examined. It was found that the aluminum MAS NMR chemical shift was related to the amount of phosphate present in the solid, which in turn was related to t,, t2, and the P:AI molar ratio. The results also lend support to the hypothesis that phosphate removal occurs through an adsorption process onto amorphous aluminum hydroxide, rather than through direct precipitation of aluminum phosphate. The increased understanding of aluminum and phosphate chemistry and the species formed during wastewater treatment will be useful in optimizing wastewater treatment processes.Key words: aluminum, phosphate, NMR, activated sludge, wastewater treatment.Resume : On a utilisC la RMN MAS du 2 7~1 et du "P pour Ctudier la nature de solides, contenant du phosphore et de I'aluminium, formCs au cours du traitement des eaux usCes. M&me s'ils sont difficiles caractkriser par les techniques conventionnelles, ces solides amorphes peuvent facilement &tre caractCrisCs par la RMN MAS et on obtient ainsi des informations sur leur arrangement B courte distance. Dans la presente ttude, la plupart des solides ont CtC prCcipitCs dans des conditions d'alcalinitk ClevCe semblables B celles utiliskes durant le traitement des eaux usCes. Le temps de vieillissement de l'hydroxyde d'aluminium avant I'addition du phosphate (t,), le temps de vieillissement des hydroxyphosphates d'aluminium aprks l'addition du phosphate (t,) et les rapports molaires du phosphore l'aluminium ont CtC contr81Cs alors que les effets d'un changement de ces parametres ont CtC examinks. On a trouvC que le dCplacement chimique de l'aluminium dans la RMN MAS est reliC a la quantitC de phosphate prCsente dans le solide qui, a son tour, est relie B t , , a t, et au rapport molaire P : Al. Les rCsultats supportent aussi l'hypothkse selon laquelle l'enlkvement du phosphate se produit par un processus de surface sur I'hydroxyde d'aluminium plut6t que par une prkcipitation directe du phosphate d'aluminium. La meilleure comprkhension de la chimie de I'aluminium et des phosphates ainsi que des espkces qui se forment au cours du traitement des eaux usCes sera utile pour l'optimisation dc ces procCdCs de traitement.Mots elks : aluminium, phosphate, RMN, boues activCes, traitement des eaux usCes.[Traduit par la rCd...

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Solid-state aluminium-27 nuclear magnetic resonance chemical shift and quadrupole coupling data for condensed AlO₄tetrahedra

Cited by 105 publications

References 1 publication

Fabrication, Structure and Properties of Nanostructured Ceramic Membranes

Fabrication, Structure and Properties of Nanostructured Ceramic Membranes

Structural elucidation of NASICON (Na₃Al₂P₃O₁₂) based glass electrolyte materials: effective influence of boron and gallium

Investigations of aluminum hydroxyphosphates and activated sludge by ²⁷Al and ³¹P MAS NMR

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Solid-state aluminium-27 nuclear magnetic resonance chemical shift and quadrupole coupling data for condensed AlO4tetrahedra

Cited by 105 publications

References 1 publication

Fabrication, Structure and Properties of Nanostructured Ceramic Membranes

Fabrication, Structure and Properties of Nanostructured Ceramic Membranes

Structural elucidation of NASICON (Na3Al2P3O12) based glass electrolyte materials: effective influence of boron and gallium

Investigations of aluminum hydroxyphosphates and activated sludge by 27Al and 31P MAS NMR

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Solid-state aluminium-27 nuclear magnetic resonance chemical shift and quadrupole coupling data for condensed AlO₄tetrahedra

Structural elucidation of NASICON (Na₃Al₂P₃O₁₂) based glass electrolyte materials: effective influence of boron and gallium

Investigations of aluminum hydroxyphosphates and activated sludge by ²⁷Al and ³¹P MAS NMR