Hydrolysis of condensed phosphates in an anion-exchange resin

Miyazaki, Yoshinobu; Kura, Genichiro; Tsuzuki, Hirohisa; Sakashita, Hirofumi

doi:10.1039/ft9969203587

Cited by 19 publications

(11 citation statements)

References 22 publications

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“…To produce HAp in this system, much efforts should be done for increasing hydrolysis fraction of tpp. Since it is known that the hydrolysis reaction of tpp is accelerated with acids such as hydrochloric acid (HCl) 6,7 , the addition of HCl in the solution is expected to be a more suitable method for producing HAp particles. Therefore, the authors investigated the effects of the addition of HCl on the formation of HAp under the same condition examined in our previous study.…”

Section: Introductionmentioning

confidence: 99%

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PREPARATION AND CHARACTERIZATION OF CALCIUM HYDROXYAPATITE FROM FORCED HYDROLYSIS OF Ca(OH)2-TRIPHOSPHATE-HCl MIXED SOLUTION

Kandori

Matsui

2013

Phosphorus Research Bulletin

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The effects of hydrochloric acid (HCl) on the formation of calcium hydroxyapatite (HAp) particles produced by aging Ca(OH)2 and sodium triphosphate (sodium tripolyphosphate, Natpp: Na5P3O10) mixed solution at 100 o C for 18 h were examined. The effect of addition of urea was also investigated. In the absence of HCl, the spherical secondary particles with ca. 60 nm in diameter composing by aggregation of spherical primary particles with ca. 20 nm in diameter were produced. Similar aggregated secondary spherical particles were formed up to HCl concentration ([HCl]) of 8 mM. On the contrary, the particles produced at [HCl]≥12 mM were elongated to c-axis and exhibit aggregated rod-like shape, though those produced at [HCl]=20 mM were spherical aggregates with ca. 20 nm in diameter. All the particles produced at[HCl]≤16 mM were HAp, though the sample produced at 20 mM was amorphous. The specific surface areas of the samples were ranged among 84-98 m 2 /g and were fairly agreed with the estimated value of spherical primary particle with 20 nm in diameter. The in situ IR spectra of the HAp particles exhibited very small bulk OH -band at 3570 cm -1 . This result indicated that the HAp particles are produced by aggregation mechanism and OH -ions along with c-axis in the poorly crystallized primary particles were disordered. The HAp particles with Ca/P molar ratio larger than theoretical value of 1.67 were not exhibited surface P-OH groups at 3656 and 3683 cm -1 . However, the addition of urea produces CaCO3 (calcite) together with HAp and no single HAp crystal was produced. It was revealed that forced hydrolysis reaction of tpp was accelerated by HCl and aggregated secondary spherical particles with unique structure and high specific surface area were obtained.

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Section: Introductionmentioning

confidence: 99%

“…tpp: P3O10 5-) ions, is endothermic process [5][6][7] , the phosphate (orthophosphate: PO4 3-) ions can be produced slowly by heating the solution, so called as a forced hydrolysis reaction.…”

Section: Introductionmentioning

confidence: 99%

PREPARATION AND CHARACTERIZATION OF CALCIUM HYDROXYAPATITE FROM FORCED HYDROLYSIS OF Ca(OH)2-TRIPHOSPHATE-HCl MIXED SOLUTION

Kandori

Matsui

2013

Phosphorus Research Bulletin

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“…The amounts of the functional group were estimated by subtracting the amounts of acid (HCl or HClO4) remaining in the acid solutions equilibrated with the resins from the initial amounts at a sufficiently high acid concentration. The water content of the resin and the interstitial volume of the resin bed were obtained by a column operation, 14 and the volume ratio of the resin internal solution to the external solution for the bed, Rv, was then estimated. Strong and weak acid cation-exchange resins, Bio-Rad AG 50W-X4 and Bio-Rex 70 (Bio-Rad Laboratories, Inc.), of the sodium ion form were used for comparison.…”

Section: Resins and Reagentsmentioning

confidence: 99%

“…(1) with RV = 0.83 obtained by the column operation. 14 In this work, the volume ratio Rv was assumed to be equal to …”

Section: Electrolyte Concentrations In the Amphoteric Ion-exchange Rementioning

confidence: 99%

Ion Exchange and Protonation Equilibria of an Amphoteric Ion-exchange Resin in the Presence of Simple Salt

Miyazaki

Konaka

2008

ANAL. SCI.

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“…Since the hydrolysis of condensed phosphate ions, such as diphosphate (pyrophosphate, pp: P 2 O 7 4À ) and triphosphate (tripolyphosphate. tpp: P 3 O 10 5À ) ions, is an endothermic process, [18][19][20] the phosphate (orthophosphate: PO 4 3À ) ions can be produced slowly by heating the solution, a so called forced hydrolysis reaction. Therefore, it can be expected that the forced hydrolysis reaction of the mixed solution of Ca 2þ and condensed phosphate ions can be applied for producing new calcium phosphate particles with unique shape and inner structure.…”

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confidence: 99%

Preparation and Characterization of Spherical and Balloon-Like Calcium Phosphate Particles

Kandori

Tada²,

Fukusumi³

et al. 2008

Bulletin of the Chemical Society of Japan

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Calcium phosphate particles were prepared by aging a solution of CaCl 2 and sodium triphosphate (sodium tripolyphosphate, Natpp: Na 5 P 3 O 10 ) at 100-150 C for 16 h in a Teflon-lined screw-capped Pyrex test tube. The rod-like and spherical particles were precipitated at an extremely fast rate of reaction under 100 C. The spherical particles were only produced in a very narrow region at 100 C by aggregation of primary small particles. The rod-like particles were CaNa 2 P 2 O 7Á 4H 2 O but the uniform spherical ones were amorphous and the latter ones were crystallized to -Ca 2 P 2 O 7 after being calcined above 600 C. The aging temperature drastically varied the particle shape under conditions for producing uniform spherical particles; solid spherical particles were produced up to the aging temperature of 115 C but balloon-like hollow spheres were precipitated at 120 C. However, large and irregular agglomerates made up of extremely small rod-like particles were precipitated after aging the solution above 125 C. TEM observation and ICP-AES measurements revealed that the balloon-like hollow spheres were produced by dissolving the interior of solid spherical particles after reinforced their shell by the adsorption of unhydrolyzed tpp. The spherical and balloon-like calcium phosphate particles with amorphous crystal form showed high selective adsorption of H 2 O by rehydration of Ca 2þ ions by penetrated H 2 O molecules into the particles. In particular, the balloon-like hollow spheres of calcium phosphate may hold potential as drug delivery vehicles and have biocompatibility advantages.Various metal phosphates have many applications in pigments, catalysis, adsorbents, and bioceramics.

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Hydrolysis of condensed phosphates in an anion-exchange resin

Cited by 19 publications

References 22 publications

PREPARATION AND CHARACTERIZATION OF CALCIUM HYDROXYAPATITE FROM FORCED HYDROLYSIS OF Ca(OH)2-TRIPHOSPHATE-HCl MIXED SOLUTION

PREPARATION AND CHARACTERIZATION OF CALCIUM HYDROXYAPATITE FROM FORCED HYDROLYSIS OF Ca(OH)2-TRIPHOSPHATE-HCl MIXED SOLUTION

Ion Exchange and Protonation Equilibria of an Amphoteric Ion-exchange Resin in the Presence of Simple Salt

Preparation and Characterization of Spherical and Balloon-Like Calcium Phosphate Particles

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