Rapid precipitation of apatite from ethanol-water solution

Lerner, Eyal; Azoury, R.; Sarig, S.

doi:10.1016/0022-0248(89)90576-9

Cited by 54 publications

(39 citation statements)

References 23 publications

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“…Even if a decrease in crystallinity of the new CaP has been reported in some cases [32,33], ethanol is thought to enhance the CaP crystallinity [34][35][36] and to increase the crystallite size, because it increases the supersaturation in the medium [37]. Moreover, ethanol has been reported to intensify the interactions between the ions in the solution, because of the decrease in the dielectric constant [32].…”

Section: Effect Of Ethanol Concentrationmentioning

confidence: 99%

“…Based on molecular dynamics simulations, the hydration shell of PO4 3-, HPO4 2-, H2PO4 -ions has been reported to consist of 16, 20 and 20 water molecules, respectively, which are tightly bound to the ions [38]. Ethanol is able to weaken the bonds in the hydration sphere of ions dissolved in water-ethanol solutions [34,39], thus decreasing the dehydration energies and facilitating the precipitation process [39]. Upon ethanol addition to an aqueous solution of DAP, a decrease in HPO4 2-content and an increase in PO4 3-content have been reported [40].…”

Section: Effect Of Ethanol Concentrationmentioning

confidence: 99%

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Calcium phosphate coatings for marble conservation: Influence of ethanol and isopropanol addition to the precipitation medium on the coating microstructure and performance

et al. 2018

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The effect of adding ethanol and isopropanol to aqueous solutions of diammonium hydrogen phosphate, used to create a passivating layer of calcium phosphates over marble, was investigated. Thanks to its weakening effect on the hydration sphere of ions in solution, ethanol allowed complete coverage of marble surface by a crackfree and pore-free layer of octacalcium phosphate. Even better results were obtained using isopropanol, because it has lower adsorption affinity to calcite than ethanol. Treatments involving alcohols provided good acid protection and also restored cohesion among calcite grains in weathered marble.

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Section: Effect Of Ethanol Concentrationmentioning

confidence: 99%

Section: Effect Of Ethanol Concentrationmentioning

confidence: 99%

Calcium phosphate coatings for marble conservation: Influence of ethanol and isopropanol addition to the precipitation medium on the coating microstructure and performance

et al. 2018

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“…The effect of alcohols on the formation of calcium phosphates have been reported previously [32,33] and it was shown that addition of ethanol and fluoride to the initial solutions of CaCl 2 -NaH 2 PO 4 [35] to synthesize nanocrystalline hydroxyapatite by sol-gel technique at 85°C and the presence of ethanol was said to provide a thermally stable hydroxyapatite formation at a lower temperature than the other existing methods.…”

Section: Introductionmentioning

confidence: 79%

“…8. The unresolved IR absorption peaks belonging to phosphate groups near 565 and 600 cm -1 for the dried sample indicate that this sample has poor crystallinity with respect to the heated sample [33]. The broad adsorption peak between 1000-1150 cm -1 , the peak at 962 cm -1 and the peak at 473 cm -1 are assigned to PO 4 3-group vibrations.…”

Section: Characterization Of the Products Prepared In Water-etoh (50%mentioning

confidence: 92%

Synthesis of hydroxyapatite by using calcium carbonate and phosphoric acid in various water-ethanol solvent systems

Engin

Girgin

2009

Open Chemistry

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Abstract:The purpose of the present study is to synthesize hydroxyapatite by using CaCO 3 and H 3 PO 4 in various water-ethanol solvent systems.It was observed from experiments that formation of ammonium phosphate compounds hindered the formation of calcium phosphates in ethanol medium. Although the reactivity was better in aqueous medium, the carbonate contents of the products obtained were above 8.5%. Best results with a carbonate content as low as 3.82% was obtained in 50% ethanol containing mixed-aqueous medium at 80°C and the FTIR analysis showed that the product was a carbonated apatite with a calculated composition of 14CaO•4.2P 2 O 5 •CO 3 •7.2H 2 O. The amorphous and porous phosphate compound obtained with a BET surface area of 106.6 m 2 g -1 seems to be useful as adsorbent in wastewater treatment. Upon sintering of the amorphous product at 750°C, crystalline hydroxyapatite with a BET surface area of 25.9 m 2 g -1 is obtained that may be used in biomedical applications.

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“…With 10 vol% EtOH addition, the marble surface was completely covered with the new HAP coating, that appeared to be crack-free (Figure 2,b). Such a strong effect of EtOH addition may be explained considering that, in the presence of EtOH, the hydration shell of phosphate ions in the DAP solution is weakened and HAP formation is hence promoted [8].…”

Section: Resultsmentioning

confidence: 99%

Some Recent Findings On Marble Conservation By Aqueous Solutions Of Diammonium Hydrogen Phosphate

et al. 2017

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Given the lack of satisfying treatments for consolidating marble affected by thermally induced grain detachment (the so-called "sugaring"), the use of aqueous solutions of diammonium hydrogen phosphate (DAP) has recently been proposed. The idea is to form a new binding mineral (hydroxyapatite, HAP) as the reaction product between the DAP solution and the calcitic substrate. In this study, we investigated the effects of adding small quantities of ethanol (EtOH) to the DAP solution, with the aim of favoring HAP formation. The results of the study indicate that, when a 0.1 M DAP and 0.1 mM CaCl2 solution in 10 vol% EtOH is used, complete coverage of marble surface with a crack-free coating with reduced porosity is achieved (whereas no coating is formed without EtOH addition). This is thought to be a consequence of the weakening of hydration shells of phosphate ions in the DAP solution, thanks to the presence of ethanol molecules. When used to restore mechanical properties of weathered marble, the treatment with 10 vol% EtOH was found to significantly improve the dynamic elastic modulus after a single application and to completely restore it after a second application.

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Rapid precipitation of apatite from ethanol-water solution

Cited by 54 publications

References 23 publications

Calcium phosphate coatings for marble conservation: Influence of ethanol and isopropanol addition to the precipitation medium on the coating microstructure and performance

Calcium phosphate coatings for marble conservation: Influence of ethanol and isopropanol addition to the precipitation medium on the coating microstructure and performance

Synthesis of hydroxyapatite by using calcium carbonate and phosphoric acid in various water-ethanol solvent systems

Some Recent Findings On Marble Conservation By Aqueous Solutions Of Diammonium Hydrogen Phosphate

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