A kinetic study of precipitation from supersaturated calcium phosphate solutions

Kemenade, M.J.J.M. van; Bruyn, P.L de

doi:10.1016/0021-9797(87)90490-5

Cited by 178 publications

(115 citation statements)

References 29 publications

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“…5 In high or medium supersaturated solutions formation of apatite always seems to be preceded by the precipitation of one or more precursor phases. Table 2.2 provides a listing of calcium phosphate phases indicating that the phosphates precipitate in a sequence of compounds.…”

Section: Kinetic Results -Formation Of Crystalline Calcium Phosphatesmentioning

confidence: 99%

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Final Report - Assessment of Potential Phosphate Ion-Cementitious Materials Interactions

Naus¹,

Mattus²,

Dole³

2007

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The objectives of this limited study were to: (1) review the potential for degradation of cementitious materials due to exposure to high concentrations of phosphate ions; (2) provide an improved understanding of any significant factors that may lead to a requirement to establish exposure limits for concrete structures exposed to soils or ground waters containing high levels of phosphate ions; (3) recommend, as appropriate, whether a limitation on phosphate ion concentration in soils or ground water is required to avoid degradation of concrete structures; and (4) provide a "primer" on factors that can affect the durability of concrete materials and structures in nuclear power plants.An assessment of the potential effects of phosphate ions on cementitious materials was made through a review of the literature, contacts with concrete research personnel, and conduct of a "bench-scale" laboratory investigation. Results of these activities indicate that: no harmful interactions occur between phosphates and cementitious materials unless phosphates are present in the form of phosphoric acid; phosphates have been incorporated into concrete as set retarders, and phosphate cements have been used for infrastructure repair; no standards or guidelines exist pertaining to applications of reinforced concrete structures in high-phosphate environments; interactions of phosphate ions and cementitious materials has not been a concern of the research community; and laboratory results indicate similar performance of specimens cured in phosphate solutions and those cured in a calcium hydroxide solution after exposure periods of up to eighteen months. Relative to the "primer," a separate NUREG report has been prepared that provides a review of pertinent factors that can affect the durability of nuclear power plant reinforced concrete structures. iv v

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Section: Kinetic Results -Formation Of Crystalline Calcium Phosphatesmentioning

confidence: 99%

“…At lower pH the calcium hydroxyapatite is preceded by octacalcium phosphate and brushite. 5 Thus these phosphates will act as precursors for formation of calcium hydroxyapatite since the calcium hydroxyapatite is the most thermodynamically stable phase. Table 2.3.…”

Section: Kinetic Results -Formation Of Crystalline Calcium Phosphatesmentioning

confidence: 99%

Final Report - Assessment of Potential Phosphate Ion-Cementitious Materials Interactions

Naus¹,

Mattus²,

Dole³

2007

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“…Recall that the pellet reactor ef ciency depends not only on pH but also on the hydrodynamic conditions (Montastruc et al, 2002a). Moreover, the conversion rate depends on calcium and phosphate ion concentrations, as well as on supersaturation, ionic strength, temperature, ion types, pH but also on time (solid-solid transformation), as noted in the literature (Baronne and Nancollas, 1977;Van Kemenade and de Bruyn, 1987;Boskey and Posner, 1973).…”

Section: Process Descriptionmentioning

confidence: 91%

“…The different forms of crystallized calcium phosphate are presented in Table 1. It is mentioned in the literature (Van Kemenade and de Bruyn, 1987) that phosphate precipitation by calcium salts leads to the formation of both dicalcium phosphate dihydrate (DCPD) and amorphous calcium phosphate (ACP) for a pH value of 7 and only to amorphous calcium phosphate (ACP) within a pH range of 9-10.5. Some experiments carried out in a previous work at a temperature of 26¯C ( Van Kemenade and de Bruyn, 1987) for a pH range of 6-7.4 followed by the evolution of the different calcium phosphate forms.…”

Section: Assumptionsmentioning

confidence: 99%

A General Framework for Pellet Reactor Modelling: Application to P-Recovery

Montastruc

Azzaro‐Pantel

Biscans

et al. 2003

Chemical Engineering Research and Design

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E mphasis in recent years has been focused on improving processes which lead to enhanced phosphate recovery. This paper studies the precipitation features of calcium phosphate in a uidized bed reactor in a concentration range between 4 and 50 mg l 1 and establishes the conditions for optimum phosphate removal ef ciency. For this purpose, two models are coupled for predicting the pellet reactor ef ciency. First, a thermodynamical model is used for predicting calcium phosphate precipitation vs. initial conditions (pH, [P], [Ca], temperature). The second one is a reactor network model. Its parameters are identi ed by an optimization procedure based on simulated annealing and quadratic programming. The ef ciency is computed by coupling a simple agglomeration model with a combination of elementary systems representing basic ideal ow patterns (perfect mixed ow, plug ow, etc.). More precisely, the superstructure represents the hydrodynamical conditions in the uidized bed. The observed results show that a simple combination of ideal ow patterns is involved in pellet reactor modelling, which seems interesting for a future control. The experimental prototype used for validation purpose is rst described. Then, the thermochemical model is presented for calcium phosphate precipitation. The third part is devoted to the reactor networkoriented model. The approach presented is nally validated with experimental runs.

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“…These ions can inhibit crystallization. Therefore, the second coating formed a thick, homogenous calcium phosphate layer compared to the first coating [24][25][26][27][28][29] . As shown in the EDS results, Mg was not detected in the second coating, unlike the first coating.…”

Section: Resultsmentioning

confidence: 99%

The biomimetic apatite-cefalotin coatings on modified titanium

et al. 2012

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Dental implant failure often occurs due to oral bacterial infection. The aim of this study was to demonstrate that antibiotic efficacy could be enhanced with modified titanium. First, the titanium was modified by anodization and heat-treatment. Then, a biomimetic coating process was completed in two steps. Surface characterization was performed with scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. Release of antibiotic was evaluated by UV/VIS spectrometry, and the antibacterial effect was evaluated on Streptococcus mutans. After the second coating step, we observed a thick homogeneous apatite layer that contained the antibiotic, cefalotin. The titanium formed a rutile phase after the heat treatment, and a carbonated apatite phase appeared after biomimetic coating. We found that the modified titanium increased the loading of cefalotin onto the hydroxyapatite coated surface. The results suggested that modified titanium coated with a cefalotin using biomimetic coating method might be useful for preventing local post-surgical implant infections.

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A kinetic study of precipitation from supersaturated calcium phosphate solutions

Cited by 178 publications

References 29 publications

Final Report - Assessment of Potential Phosphate Ion-Cementitious Materials Interactions

Final Report - Assessment of Potential Phosphate Ion-Cementitious Materials Interactions

A General Framework for Pellet Reactor Modelling: Application to P-Recovery

The biomimetic apatite-cefalotin coatings on modified titanium

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