Hochfeld‐<sup>27</sup>Al‐NMR‐Untersuchungen zur Aluminiumkoordination in kristallinen Aluminiumphosphaten

Müller, D.; Grunze, I.; Hallas, E.; Ladwig, G.

doi:10.1002/zaac.19835000511

Cited by 80 publications

(24 citation statements)

References 14 publications

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“…6). The tetrahedral aluminum signal at 38 ppm indicated anhydrous AIPO,, while the octahedral resonance at -16 ppm had been previously described by Muller et al as characteristic of solid Al(H,PO,), (25).…”

Section: Investigation Of Aluminum Phosphate Precipitated At Low Phmentioning

confidence: 54%

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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Section: Investigation Of Aluminum Phosphate Precipitated At Low Phmentioning

confidence: 54%

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

Duffy¹,

vanLoon²

1995

Can. J. Chem.

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“…A similar correlation of 618 O of 27A1 with A1-O-P bond angle as for 295i in SiO 2 exists [216]. Metava¡ (A1PO4 9 2H20 ) has a well defined Al(~) coordination [217] while ammonium and alkali phosphates have both A1(4) and Al(~) coordinations [218]. For compounds with phosphorus nnn the 27A1 shift ranges associated with Al(4) and Al(~) are typically (25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35) ppm below the shift ranges associated with aluminates (Fig.…”

Section: Aluminophosphatesmentioning

confidence: 64%

Application of27Al NMR techniques to structure determination in solids

1993

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Abstraer. There have been great improvements in the quality of 27A1 NMR spectra from solids over the last decade. The impact of this technique on structure determination fora wide range of solids is briefly reviewed. Emphasis is placed on the effects arising from the presence of the quadrupolar interaction and strategies that allow unambiguous spectral interpretation. It is demonstrated that in addition to the chemical shift, the quadrupolar interaction itself can be a rich source of local information about solids. The insight obtalned from 27A1 NMR hato atomic level structure often contains surprises, such that previous models of structure and properties have to be reassessed.

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“…2a) presents two peaks at 40.3 and -10.1 ppm related to tetrahedral and octahedral aluminium, respectively. Miiller et al [15] attribute the great shift for both signals as compared to aluminium oxides to the influence of phosphorus atoms located in the second coordination sphere. By heating at 120~ octrahedral aluminium rums out to be tetrahedral (Fig.…”

Section: Resultsmentioning

confidence: 98%

Study of acid-base properties of a SiO2−AlPO4 (80∶20 W/W) catalyst

Aramendía

Boráu

Garcı́a

et al. 1999

React Kinet Catal Lett

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Hochfeld‐²⁷Al‐NMR‐Untersuchungen zur Aluminiumkoordination in kristallinen Aluminiumphosphaten

Cited by 80 publications

References 14 publications

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

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

Application of27Al NMR techniques to structure determination in solids

Study of acid-base properties of a SiO2−AlPO4 (80∶20 W/W) catalyst

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Hochfeld‐27Al‐NMR‐Untersuchungen zur Aluminiumkoordination in kristallinen Aluminiumphosphaten

Cited by 80 publications

References 14 publications

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

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

Application of27Al NMR techniques to structure determination in solids

Study of acid-base properties of a SiO2−AlPO4 (80∶20 W/W) catalyst

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Product

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Hochfeld‐²⁷Al‐NMR‐Untersuchungen zur Aluminiumkoordination in kristallinen Aluminiumphosphaten

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

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