Radioisotope determination of the surface concentrations of calcium and phosphorus on hydroxylapatite in aqueous solution

Kukura, M.; Bell, L. C.; Posner, A. M.; Quirk, J. P.

doi:10.1021/j100650a019

Cited by 73 publications

(43 citation statements)

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“…This would simplify our system by excluding the third and sixth equilibria of Table 2. However, we consider that no real credit can be given to the ascription made by Wu et al Indeed equal concentrations of (Ca-OH) and (P-OH) is unlikely for apatite (27), and there was no chemical evidence to reinforce the attribution of the constants although it could have been given in several different ways due to the equal concentrations of both sites.…”

Section: Exchange Equilibriamentioning

confidence: 79%

“…The theoretical sorption capacity at the surface can be estimated from the concentration of PO 4 groups in the superficial plane of crystal cells. Using a calculation similar to that used by Kukura et al (27) and considering that, due to the elongated shapes of crystallites, the main contribution to the surface results from [100] faces, we obtained a theoretical surface P concentra- The XPS results indicate that selenium is not homogeneously distributed in the solid, but they cannot discriminate between groups located on the surface of crystal cells and groups in a layer including a few superficial cells.…”

Section: Estimated Thickness Of the Sorption Layermentioning

confidence: 99%

See 1 more Smart Citation

Sorption of Selenite (SeO32−) on Hydroxyapatite: An Exchange Process

Monteil-Rivera

Fédoroff

Jeanjean

et al. 2000

Journal of Colloid and Interface Science

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Section: Exchange Equilibriamentioning

confidence: 79%

Section: Estimated Thickness Of the Sorption Layermentioning

confidence: 99%

Sorption of Selenite (SeO32−) on Hydroxyapatite: An Exchange Process

Monteil-Rivera

Fédoroff

Jeanjean

et al. 2000

Journal of Colloid and Interface Science

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“…[4], and the brackets symbolize molar concentrations (mol/dm 3 ). (33), respectively. According to the proposed adsorption model the protonated amino group may form complexes with the negatively charged HAP surface, whereas the deprotonated carboxyl group orients itself with the maximum possible distance from the surface because of electrostatic repulsion.…”

Section: Figmentioning

confidence: 97%

Model Studies on the Interaction of Amino Acids with Biominerals: The Effect of L-Serine at the Hydroxyapatite–Water Interface

Spanos

Klepetsanis

Koutsoukos

2001

Journal of Colloid and Interface Science

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“…Exchange experiments have been carried out by a number of investigators [1-6V In some cases, the studies were conducted under conditions where other interactions such as dissolution, prec ipitation and hydrolysis were also present and, therefore, in suc h cases th e application of exchange I kinetics is evidently not valid. We have chosen to reinterpret the data collected by Avni melech [4][5][6][7]. These experiments were performed under th e conditions of saturation at various hydrogen ion concentrations at 25°C using a homogeneous nonlabile solid phase which was stab ilized by prolonged boiling.…”

Section: Introductionmentioning

confidence: 99%

“…Th e scatterin g of data may be related to the variable contamination of th e surface laye rs of hydroxylapatite [10,11]. Probabl y, th e surface concentrations of constituent ions are best obtained at th e point of zero charge of the substrate [5]. Mean ± standard dev iati on 1.…”

mentioning

confidence: 99%

Isoionic isotope exchange with hydroxylapatite and the dilution effect

Misra¹

1979

J. RES. NATL. BUR. STAN.

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Isoioni c isotope exchange data of 45Ca2+ and 32PO."-in a saturated soluti on with hydroxylapatite at 25°C, collected by Avnimelech, have been re int erpre ted on the basis that the processes con s isted of three pool s: hyd ration shell , s urface layer a nd " rec rys talli zati on of crystallit es." These processes are regarded as st ri ctl y separable. Thi s theoreti call y a ll ows: (i) a quantitative e valuati on of the constants in vo lved in the processes; (ii ) an estimati on of the exc han ge c apaciti es of hydration and s urface laye rs (fast poo ls) whi ch may be pH-de pe nd e nt ; a nd (iii ) a dete rminati on of the isoioni c exchange rat e constant s. The consta nts are esse nti a ll y the same for Ca 2 + a nd P04 3 -at a give n 1'1 -1 if the cross-sectional areas of the ions a re take n as 23 A,2 and 33 A,2 respectively: they, perhaps, inc rease linearly with the hyd roge n ion conce ntrati on of the soluti ons.The effects of three consec utive abru pt dilutions of the radioactive ion s without c hanging the concentrations (or pH) of the nonradioactive co mpon e nt s of the so luti on are predi ctab le by a mathemati cal mode l based on th e comple te reversibility of the two fa s t pools and the kineti cs of the in-evers ible third poo l.Ke y words: Dilution effec t, at same pH and concentrati on; hydration s hell , role of; hydroxylpatite , at diffe re nt pH s; isotopi c excha nge, isoion ic; recrysta lli zat ion , role of; s urface layer, role or. . IntroductionThe determination of th e iso ioni c isotope exchange rates of 45Ca2+ and 3 2 P04 3 -in a saturated soluti on with hydroxy lap-. atite ("bone mineral", OHAp) may have some fundam ental role in understand ing th e growth, dissolution, adhesion mechani sms and calcium and phosphate homeostasis of bone and tooth ti ssues. An adequate experimental stud y with proper th eoretical understanding of the exc hange mechanism should also throw some light on the surface chem istry of " hydroxylapatite which is of immense importance in th e fi elds . of mineral processing and agriculture in addition to dental and medical research. Exchange experiments have been carried out by a number of investigators [1-6V In some cases, the studies were conducted under conditions where other interactions such as dissolution, prec ipitation and hydrolysis were also present and, therefore, in suc h cases th e application of exchange I kinetics is evidently not valid. We have chosen to reinterpret the data collected by Avni melech [4][5][6][7]. These experiments were performed under th e conditions of saturation at various hydrogen ion concentrations at 25°C using a homogeneous nonlabile solid phase which was stab ilized by prolonged boiling. We have treated Avnimelec h's full data, although partial treatments have been reported [4,7]Various th eoreti cal mod els have bee n proposed to explain th e kin etics of the iso ion ic exchange process with hydroxylapatite. In general , the iso ionic exchange is assumed to comprise three [1,4, 91] or more [3 , 8] processes ,...

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Radioisotope determination of the surface concentrations of calcium and phosphorus on hydroxylapatite in aqueous solution

Cited by 73 publications

References 4 publications

Sorption of Selenite (SeO32−) on Hydroxyapatite: An Exchange Process

Sorption of Selenite (SeO32−) on Hydroxyapatite: An Exchange Process

Model Studies on the Interaction of Amino Acids with Biominerals: The Effect of L-Serine at the Hydroxyapatite–Water Interface

Isoionic isotope exchange with hydroxylapatite and the dilution effect

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