神鳥 和彦

Ferric phosphate particles were prepared by aging a solution dissolving Fe(ClO4)(3) and H3PO4 at 40-80 degrees C for 16 h in a Teflon-lined screwcapped Pyrex test tube. The spherical or agglomerated fine particles were only precipitated with an extremely fast rate of reaction. The spherical particles were only produced at a very narrow region in fairly low pH solutions. TEM observation revealed that these particles grew in spherical structure by aggregation of primary small particles. The size of spherical particles was decreased by increase in the solute concentration or raising the aging temperature. Therefore, the formation of spherical particles was explained by a polynuclear layer mechanism proposed by Nielsen. The uniform spherical particles produced are amorphous, but they were crystallized to FePO4 after calcining above 600 degrees C. It was suggested that the voids between the primary particles within the secondary agglomerated particles constitute mesopores. The Fe/P molar ratio determined and weight loss in TG curves gave the chemical formulas of the particles as Fe(PO4)(x)(H2PO4)(y)center dot nH(2)O (x: 0.93-1.00, y: 0-0.22, n: 2.4-2.7). The amorphous spherical ferric phosphate particles showed a high selective adsorption of H2O by penetration of H2O molecules into ultramicropores, produced after outgassing pretreatment, of that size is smaller than N-2 molecule. The more particles grew, the more adsorption selectivity of H2O became remarkable. (c) 2006 Elsevier Inc. All rights reserved.

The structure and composition of the rust formed on the binary Fe-Ni Fe-Cr. and Fe-Cu alloys exposed at different situations for 2 years and 3 years were investigated by N-2 adsorption, Fourier transform infrared (FTIR), transmission electron microscopy (TEM), and inductively coupled plasma-atomic emission spectrometry (ICP-AES) to explore the role of alloying metals in the corrosion resistance of weathering steels. The rust particles formed in all exposure sites were strongly aggregated and microporous. The specific surface area (SA) obtained by N-2 adsorption decreased and then increased by increasing the contents of Ni and Cr. The increase of SA, that is, the reduction of particle size of rust, was remarkable in the exposure site with a high airborne salinity. This result verifies that alloying metals are effective for the corrosion restraint of steels in Cl- environments such as coastal and marine districts. The content ratio of alpha-FeOOH to gamma-FeOOH in rust (alpha/gamma) showed a maximum at alpha/gamma = ca. 0.5, and the corroded amount was very small at alpha/gamma > ca. 1.5, indicating that the alpha/gamma ratio reflects the stability of rust at alpha/gamma > ca. 0.5.

Zinc hydroxide chloride particles were synthesized by hydrolysis of ZnCl2 solutions dissolving AlCl3 at different atomic Al/Zn ratios from 0 to 1.0 and characterized by various techniques. Increasing Al/Zn ratio changed the crystal phases of the products as ZnO -> ZnO + ZHC (Zn-5(OH)(8)Cl-2 (.) H2O) -> ZHC -> LDH (layered double hydroxides, Zn-Al-Cl) and the particle morphology as agglomerates (ZnO) -> fine particles (ZnO) plates (ZHC)+ rods (ZnO)-> plates (ZHC)-> plates (LDH). The atomic Cl/Zn ratios of LDH particles of formed at Al/Zn >= 0.3 were ca. 0.3 despite the increase of Al/Zn ratio, being due to the intercalation of CO32- into the LDH crystal. The OH- content of LDH estimated by TG was reduced by the deprotonation of OH- to Counteract the excess positive charge produced by replacing Zn(II) with Al(III). ZHC exhibited a high adsorption selectivity of H2O. (c) 2006 Elsevier Inc. All rights reserved.

The influence of amino acids on the formation of hematite particles from a forced hydrolysis reaction of acidic FeCl3 solution was examined. The spherical particles were produced on the systems with L-phenylalanine (L-Phe), L-serine (L-Ser) and L-alanine (L-Ala), though L-glutamine (L-Gln) and L-glutamic acid (L-Glu) gave ellipsoidal hematite particles. This morphological change in hematite particles is consistent with the order of stability constant of amino acids against to Fe3+ ions (K). The hematite particles produced with L-Glu, L-Gln and L-Ser were highly porous because they are formed by aggregation of cluster particles. These particles exhibited microporous behavior by outgassing the particles below 200 degrees C while they changed to mesoporous after treating above 300 degrees C by elimination of amino acids molecules remained between the cluster particles within the hematite particles. The hematite particles strongly depended on the nature of amino acids such as alternation of solution pH and adsorption affinity to beta-FeOOH and/or polynuclear primary (PN) particles. The systems on L-Ala and L-Phe, showing very rapid phase transformation from beta-FeOOH to hematite, exhibited the Ostwald ripening. A rotational particle preparation procedure suggested that the morphology of hematite particle is governed by the mode and strength of amino acid adsorption onto beta-FeOOH and/or PN particles. (c) 2005 Elsevier Inc. All rights reserved.

The artificial beta-FeOOH rusts were synthesized by oxidation of FeCl2 solutions and hydrolysis of FeCl3 solutions. Various Na salts such as sulfate, biphosphate, nitrate, and silicate were added to the starting solutions at different anion/Fe molar ratios of 0-0.05. The XRD patterns of the products showed only the diffraction peaks of beta-FeOOH. The crystallinity of the products was noticeably reduced by adding SO42- and HpO(4)(2-) but slightly influenced by adding NO3-. The addition of SiO32- markedly crystallized the products by the hydrolysis of FeCl3. The N-2 adsorption revealed that the products with SO42- were porous particles assembled by beta-FeOOH subcrystals. SO42- and HPO42- strongly coordinating to Fe(III) markedly lowered the crystallinity of the products and remained in the formed particles. (c) 2005 Published by Elsevier Ltd.

Cadmium-calcium hydroxyapatite (CdCaHap) solid solutions with different atomic ratios Cd/(Cd + Ca) (X-Cd) of 0-1 were synthesized by a wet method and characterized by various means. X-Cd of ail the obtained solid solution particles was slightly larger than Cd/(Cd + Ca) atomic ratio in the starting solutions ([X-Cd]), that is, Cd2+ ions were a little more easily incorporated into hydroxyapatite (Hap) crystals compared to Ca2+ ions. With increasing Cd2+ content, the unit cell dimensions a and c decreased, the particles became large spherical agglomerates, and the specific surface area decreased. The amount of CO2 irreversibly adsorbed on CdCaHap was lower on average than those on the other Hap particles. (c) 2005 Elsevier B.V. All rights reserved.

Particles of carbonated barium-calcium hydroxyapatite solid Solutions (BaCaHap) with different Ba/(Ba + Ca) atomic ratios were prepared by a wet method at 100 degrees C and characterized by various means, The crystal phases and qructures of the products strongly depended on the composition of the starting solution, that is, the Ba/(Ba+Ca) atomic ratio (vertical bar X(Ba)vertical bar) and H3PO4 concentration ([H3PO4]) in the solution. BaCaHap with X-Ba <= 0.43 could be prepared at vertical bar X(Ba)vertical bar = 0.7 by changing vertical bar H(3)PO(4)vertical bar bill could never be obtained at [X-Ba] = 0.8-0.95 regardless of vertical bar H(3)PO(4)vertical bar. The carbonated calcium hydroxyapatite particles prepared at vertical bar X(Ba)vertical bar = 0 were line and short rod-shaped particles (ca. 14 x 84 nm). With increasing vertical bar X(Ba)vertical bar from 0 to 0.8. the particles obtained became large spherical agglomerates. The carbonated barium hydroxyapatite particles formed at vertical bar X(Ba)vertical bar = 1 were long rod-shaped agglomerates (ca. 0.2 x 2 mu m) of fine primary particles. The amount of CO2 adsorbed irreversibly on a series of BaCaHaps showed a Minimum at Ma + Ca)/(P + (7) atomic ratio of around 1.56 which agreed well with the minimum cation/P ratio obtained for the other hydroxyapatites was already reported. (c) 2005 Elsevier Inc. All rights reserved.

To clarify the adsorption mechanism of proteins onto calcium hydroxyapatite (Hap), the kinetic studies of dissolution and ion-exchange properties of synthetic Hap particles in the absence and presence of proteins were examined at 15 degrees C. In the absence of proteins, Hap particles slightly dissolved to give low amounts of calcium ([Ca2+] = 0.09-0.14 mu mol m(-2)) and phosphate [PO43-] = 0.01-0.08 mu mol m(-2)) ions in KCl, CaCl2, BaCl2 and AlCl3 solutions. The [Ca2+] increased with increase in the Ca/P ratio of Hap, while the [PO43-] decreased. The [Ca2+] and [PO43-] were independent of the ionic strength. Ba2+ and AI(3+) ions were completely ion-exchanged with calcium ions in Hap lattice within 2 hr. The solution pH was increased by 1.1-1.8 after the dissolution of OH- ions on the Hap surface. In the presence of bovine serum albumin (BSA), the Hap particles dissolved slightly faster than the systems without protein. This fact was explained by a complexation of dissolved ions to functional groups of BSA. The adsorption of BSA induced a reduction of [Ca2+] and [PO43-] in the aqueous medium and minima appeared on [Ca2+] and [PO43-] profiles before the BSA adsorption reached a saturation. This result suggests that the adsorption of BSA onto Hap is governed by [Ca2+] ions complexing to BSA molecules (binding effect) together with the operation of [Ca2+] ions exposing on the Hap surfaces by dissolution of OH- ions, so-called "C-sites". The addition of BaCl2 and AlCl3, BSA steeply increased the amounts of adsorbed BSA (n(BSA)) at the initial adsorption step by the strong binding effect of these di- and trivalent cations between BSA and Hap. However. after eliminating these cations from the Hap surface by the ion-exchange reaction, the binding effects disappeared BSA I and n(BSA) decreased. Since the number of functional groups is small, the binding effect of the counter ions was only slightly detected for the systems with di- and trivalent ions on the adsorption systems of lysozyme (LSZ).

Synthetic colloidal calcium hydroxyapatite (Ca-10(PO4)(6)(OH)(2): CaHap) was treated with pyrophosphoric acid (H4P2O7: PP) in acetone and the materials were characterized by XRD, TEM, FTIR, and N-2 and H2O adsorption measurements. XRD patterns and morphology of CaHap particles were essentially not changed by the modification. The additional amount of PO4 of CaHap was increased with an increase of PP concentration and the Ca/P molar ratio of the particles decreased from 1.62 to 0.81. IR results indicated that the isolated surface P-OH band developed with increasing the PP concentration up to 6.0 mmol dm(-3) by the reaction of isolated surface P-OH groups of CaHap and pyrophosphoric acids. Above 10.2 mmol dm(-3), a hydrogen-bonding surface P-OH band appeared at 2913 cm(-1) and enlarged with increasing the PP concentration, while the isolated Surface P-OH band was weakened. The results of N-2 and H2O adsorption measurements revealed that the modified particles aggregated compared to the unmodified ones, which would be due to the formation of hydrogen-bonding surface P-OH groups among the particles. (C) 2004 Elsevier Inc. All rights reserved.

The influence of polymers on the formation of hematite particles from forced hydrolysis of acidic FeCl3 solution was investigated using vinyl series polymers with different functional groups. The disk-like hematite particles were produced from forced hydrolysis of acidic FeCl3 solution in the presence of polyvinyl alcohol (PVA: 0-1 wt%). On the other hand, spherical particles were produced by addition of very small amounts of polyacrylamide (PAAm: 0-0.004 wt%). The size of spherical particles was slightly decreased with increase in the concentration of PAAm. The ellipsoidal particles were precipitated by addition of a very low concentration of polyacrylic acid (PAAc: 0-0.004 wt%). The effect of polymers on the hematite particle formation was expressed in the order of PVA < PAAm < PAAc that is in the reverse order from their average molecular weight. Therefore it was concluded that the effects of polymer molecules strongly depend on the functional groups of polymers. The secondary reduction steps of the concentration of Fe3+ ions ([Fe]) were observed during aging. This secondary step of [Fe] corresponded to the time of the complete phase transformation from beta-FeOOH to hematite. Thus one was forced to conclude that the dissolution of beta-FeOOH particles is a rate-determining step in the reaction sequence for the systems with polymers. A rotational particle preparation procedure suggested that the morphology of hematite particle is governed by the mode and strength of polymer adsorption onto beta-FeOOH and polynuclear primary particles. (C) 2004 Elsevier Inc. All rights reserved.

Thermodynamic parameters have obtained in the present study by measuring the adsorption isotherms of bovine serum albumin (BSA: isoelectric point (iep) = 4.7), myoglobin (MGB: iep = 7.0) and lysozyme (LSZ: iep = 11.1) onto calcium hydroxyapatite (Hap) at different temperatures (15 degrees C and 35 degrees C) in an attempt to clarify the adsorption mechanism of such proteins. The adsorption affinity of proteins strongly depended on the Ca/P molar ratio of the Hap particles. In the case of BSA, the initial slopes of the adsorption isotherms increased remarkably with an increase in the Ca/P ratio. In contrast, the initial slopes of the adsorption isotherms for LSZ changed gradually with increasing Ca/P ratio. Finally, no Ca/P ratio dependence was observed in the MGB system. These results were explained in terms of the electrostatic interaction between the proteins and Hap. The negative values of Delta G(ads) for the BSA system increased from -34.0 kJ/mol to -36.1 kJ/mol with increasing Ca/P ratio whereas those for the LSZ system decreased from -37.9 kJ/mol to -30.8 kJ/mol. A diminished dependence of Delta G(ads) on the Ca/P ratio was observed in the MGB system. The adsorptions of LSZ and MGB onto Hap were exothermic which again supports an electrostatic attraction mechanism. In contrast, the adsorption of BSA onto Hap exhibited a large positive value for Delta H-ads' indicating that the process was endothermic. The Delta S-ads value of the LSZ system was negative while those for the BSA and MGB systems were positive. Positive values for Delta S-ads, especially for the BSA system, indicate that the adsorption processes for BSA and MGB (both with a lower structural stability) were driven by an entropy gain, i.e. Delta S-ads > 0. Adsorption of these proteins onto the Hap surface was accompanied by a structural rearrangement.

A 0.5 dm(3) aqueous solution of 0.1 M FeCl3 dissolving 1 wt% poly(vinyl alcohol) (PVA) was treated hydrothermally in a stainless steel autoclave at various temperatures (T-h=110-200 degreesC). Highly ordered red corpuscle-like hematite particles around 2 mum in diameter were produced after aging the solution at T-h=110 degreesC for 7 days, though large numbers of spherical PVA microgels around 2-4 mum in diameter were produced together with the red corpuscle-like particles at T(h)greater than or equal to120 degreesC. The number of red corpuscle-like hematite particles decreased but that of spherical PVA microgels increased with increasing T-h, leading to the proposal that the method carried out in the present study will become a new synthetic method of polymer microgels. The ferric ions acted as a cross-linking agent to make PVA insoluble in water. The red corpuscle-like hematite particles produced at T-h=110 degreesC had high specific surface areas and showed high mesoporosity. The mesoporosity appeared to be more pronounced after evacuating the particles above 300 degreesC. The diameter of the mesopores after evacuation above 300 degreesC ranged from 2 to 20 nm, with a maximum at around 5-6 nm. The H2O and N-2 adsorption experiments revealed that there are no ultramicropores in the particles. The H2O and CCl4 adsorption experiments further disclosed that the surface hydrophobicity of the particles is low even though PVA molecules remain after evacuation of the particles at 100-400 degreesC. Furthermore, the micropores produced after evacuation of the particles at 400 degreesC exhibited a high size restriction effect, i.e., the micropores produced were accessible to H2O (diameter 0.253 nm) and N-2 (diameter 0.318 nm) molecules but not to CCl4 (diameter 0.514 nm).

Magnesium-calcium hydroxyapatite solid solution (MgCaHap) particles were immersed into solutions containing Ca2+ ions under different conditions where Ca2+ concentration, immersion period, solution pH and temperature were varied. Mg2+ ions in the particles were released into the solution accompanying the incorporation of Ca2+ ions from the solution into the particles by the treatment, which demonstrates that Mg2+ in MuCaHap was exchanged by Ca2+. The ion-exchange equilibrium was attained within a short time of 15-30 min. The ion-exchange was promoted by raising the Ca2+ concentration and solution temperature and by lowering the solution pH. The exchange of Mg2+ with Ca2+ was shown to take place by the dissolution of surface layer of the MgCaHap particles and the recrystallization of a new hydroxyapatite (Hap) layer on the particles. (C) 2004 Elsevier B.V. All rights reserved.

This paper presents data on adsorption of immunogamma globulin (IgG) onto synthetic rodlike calcium hydroxyapatite particles (CaHaps) with various particle lengths and calcium/phosphate (Ca/P) atomic ratios ranging from 1.54 to 1.65 and compares the obtained results to those of acidic (bovine serum albumin, BSA), neutral (myoglobin, MGB), and basic (lysozyme, LSZ) proteins reported before. The effect of electrolyte concentration on IgG adsorption was also examined. The initial rate of IgG adsorption was similar to that of BSA and was slower than that of MGB and LSZ. This fact was interpreted by the difference in the structural stability and molecular weight of these proteins. The isotherms of I-G adsorption onto the CaHap particles were of pseudo-Langrnuir type. The saturated amount of adsorbed IgG IgG values (n(s)(IgG)) for the particles with mean particle length less than 70 nm decreased with increasing Ca/P ratio. The adsorption behavior of IgG molecules was very similar to that of basic LSZ, though IgG has zero net charge. The n(s)(IgG) value was increased with increased mean particle length of CaHaps; the relationship was less significant than that for BSA but similar to those for MGB and LSZ. The similar adsorption behavior of IgG and LSZ suggested that the F(ab) parts of IgG molecules preferentially adsorb onto CaHap to provide the reversed Y-shaped conformation of IgG. The change of the adsorption mode of IgG molecules from the reversed Y-shaped conformation NG to side-on by "spreading" the F(c) part of IgG molecules onto the particle surface over a longer adsorption time was suggested. The n(s)(IgG)value was increased with increasing electrolyte concentration by screening the intra- and intermolecular electrostatic interactions of proteins. (C) 2004 Elsevier Inc. All rights reserved.

A 0.1 M FeCl3 aqueous solution was hydrothermally treated in a 1.5-dm(3) stainless steel autoclave at varied temperatures (T-h: 110-200 degreesC). Highly ordered cubic particles with uniform micropores 0.8 nm in diameter are produced at T-h = 115 degreesC, although the cubic particles become less uniform with wide pore size distribution by raising the T-h. (C) 2003 Elsevier Inc. All rights reserved.

The artificial rust particles were prepared from ZnCl2 solutions dissolving AI(III), Fe(III), Fe(II), Ni(II), Co(II) and Mg(II) at different atomic ratios from 0 to 0.3 in metal/Zn. With increasing metal/Zn the crystal phases of the products turned following as ZnO --> a mixture of ZnO and Zn-5(OH)(8)Cl-2 . H2O (ZHC) --> ZHC. Al(III) most facilitated the formation of ZHC but Mg(II) and Fe(III) produced no ZHC. The morphology of the formed particles varied following as agglomerate --> fine --> rod --> sheet --> irregular with the increase of metal/Zn. The sheet and irregularly shaped particles were identified as ZHC and the other particles as ZnO. (C) 2003 Elsevier Ltd. All rights reserved.

To investigate the influences of metal ions on beta-FeOOH formation, the beta-FeOOH particles were prepared by aerial oxidation of FeCl2 solutions in the presence of chlorides and sulfates of Ti(IV), Fe(III), Cu(II), and Ni(II), and CrCl3 at different metal/Fe atomic ratios of 0-0.1 and characterized by X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, inductively coupled plasma, thermogravimetry and differential thermal analysis, and N-2 adsorption. The produced particles contained a large quantity of Ti(IV) and Cr(III) but little Cu(II) and Ni(II). All the added metal chlorides and sulfates made the formed particles less crystalline. The sulfate and chloride of Ti(IV) inhibited the formation of beta-FeOOH at a high Ti/Fe by a marked depression of solution pH by hydrolysis of Ti(IV). The metal sulfate ions effectively reduced the crystallinty of beta-FeOOH to give highly microporous particles. The strong inhibitory effect of SO42- on the crystallization of beta-FeOOH can be ascribed to the adsorption of SO42- on the primary particles. This is also evident from the high content of SO42- in the formed particles. (C) 2004 The Electrochemical Society.

2002年4月からは小・中学校,2003年4月からは高等学校でも新学習指導要領が導入された。これに合わせて,教員養成系大学でも2000年度から改組と力リキュラム改革が計られ,今年の3月には初めての卒業生を送りだした。ここでは,教育職員免許法の改正に伴う教員養成系大学の力リキュラム改革と今後の教員養成に対する影響や間題点について紹介する。

The phase composition, morphology, and inner structure of the particles precipitated from a forced hydrolysis reaction of acidic Fe-2(SO4)(3) solution were examined. The shape and size of precipitated particles strongly depended on the concentration of the reactants in the starting solution, particularly on that of Fe-2(SO4)(3). The relatively lower concentration of Fe-2(SO4)(3) produced acicular or rod-like multi-domainic goethite particles, while the higher one provided irregularly shaped hydronium jarosite particles. This difference strongly depended on the pH of the aging solution; acicular goethite particles were produced at pH > 1.6 though jarosite was produced at pH < 1.5. The large goethite and jarosite particles exhibited a high microporosity. The time resolved transmission electron microscope (TEM) observation technique revealed that the rate of hydrolysis reaction for producing goethite was fast and the particle growth was almost terminated after aging for 1 day. On the contrary, the system favoring precipitation of jarosite exhibited a phase transformation from cubic and hexagonal basic iron(III) sulfate, produced in the early stage of the reaction until 10 h, to large irregular jarosite particles. (C) 2003 Elsevier B.V. All rights reserved.

beta-FeOOH particles were synthesized in the presence of Ti(IV), Al(III), and Cr(III) at metal/Fe atomic ratios of 0-0.1 by the following two methods: hydrolysis of aqueous FeCl3 solutions added to the hydrolysis products of these metal ions (subsequent hydrolysis, SH) and hydrolysis of aqueous FeCl3 solutions dissolving these metal ions (combined hydrolysis, CH). On increasing Al/Fe the particle size of the products with AlCl3 by SH method steeply rose at a low Al/Fe and then fell. The similar increase of particle size was seen in SH method with Ti(SO4)(2) though the addition of TiCl4 decreased the particle size. In CH method, Ti(IV) markedly impeded the beta-FeOOH formation but Al(III) and Cr(III) showed no influence. The particles prepared by CH and SH methods contained a large amount of Ti(IV) but a few AI(III) and Cr(III). The large spindle-shaped and rod-shaped particles produced by SH method with AlCl3 and Ti(SO4)(2) were highly microporous and poorly crystallized, indicating that the particles consist of fine primary particles and the aggregation of fine particles would be promoted by SO42-. The different influences of the metal ions on the beta-FeOOH formation were explained by their hydrolysis characteristics. (C) 2003 Elsevier Inc. All rights reserved.

The poorly crystallized steel rusts have been prepared by hydrolysis of aqueous solutions dissolving Fe(III) and different metal ions such as Ti(IV), Cr(III), Ni(II) and Cu(II) at varied atomic ratios in metal/(Fe + metal). The precipitates formed by the hydrolysis were frozen with liquid N-2 to inhibit crystallization and particle growth. The rusts produced were poorly crystalline and nanosized particles with sizes of 4-10 nm and the rust formed without adding metal ions was assigned to ferrihydrite. The crystallite size decreased from 1.1 to 0.7 nm with increasing the added metal ions. It was shown by extended X-ray fine structure and Mossbauer spectroscopy that the short-range structure of poorly crystalline rusts was disturbed by adding Ti(IV). (C) 2002 Elsevier Science Ltd. All rights reserved.

The surface structure and properties of synthetic calcium hydroxyapatite (CaHap) treated with different concentrations of F- ions at neutral pH were investigated by a variety of techniques. The adsorption isotherm of F- ions on CaHap below 0.03 mol dm-3 exhibited the Langmuir type and the saturated amount was estimated to be 1.7 ions nm-2. This value is lower than 2.88 ions nm-2 of surface OH- number calculated from the crystal structure of CaHap, proving that all the surface OH- ions are not replaced with F- ions. The deuteration of column OH- ions of CaHap was interfered with F- ions replaced for OH- ions in the entrance of OH- columns along c-axis, that is, on a b face. When the samples were treated above 0.04 mol dm-3, the surface phase of CaHap was dissolved to produce calcium fluorapatite, so that, the deuteration of column OH- ions of CaHap was more promoted than the materials treated below 0.03 mol dm-3. The surface H2PO4- and HPO42- ions of CaHap were not replaced with F- ions. © 2002 Elsevier Science B.V. All rights reserved.

The effect of poly(ethylene glycol) (PEG) on the formation of spherical hematite particles from a forced hydrolysis reaction in acidic FeCl3 solution was examined. Spherical hematite particles were precipitated under all of the conditions studied, and the diameters of the particles increased from 400 to 1500 nm (1.5 mum) with increasing PEG concentration. The rate of phase transformation from beta-FeOOH to hematite was decreased considerably at higher PEG concentrations as a result of the adsorption of PEG onto both beta-FeOOH and primary polynuclear particles. The hematite particles formed with PEG were hydrohematite with a crystal lattice distortion, and they exhibited a polycrystalline nature. The nanoporous hematite particles were produced in the presence of PEG acting as a prominent templating agent. This study indicates that the forced hydolysis reaction in the presence of PEG is a successful and simple route for producing micrometer-scale nanoporous hematite particles.

Rod-like calcium hydroxyapatites (Hap) with micrometer size were produced by supplying Ca(CH3COO)(2) and NH4H2PO4 solutions into a CH3COONH4 solution by varying their feeding rate at 85 +/- 5 degreesC and pH 7.4 +/- 0.2 under nitrogen atmosphere and vigorously stirring. The size of the Hap particles was increased with increase in feeding time (t(F)) of the solutions with increase in the t(F) the mean particle width and lengths were increased from 0.02 to 0.47 mum and from 0.12 to 5.21 mum, respectively. All these particles were highly crystallized and exhibited a single crystal and Ca-deficient natures with Ca/P atomic ratios of 1.50-1.59. TG and chemical analyses indicated that the chemical composition of the particles can be expressed to Ca10-x-y(HPO4)(x)(PO4)(6-x)(OH)(2-x-27).nH(2)O. The amount of adsorbed bovine serum albumin (BSA) onto the synthesized micrometer-sized Hap particles is strongly dependent upon their mean particle length (LP), while that of lysozyme (LSZ) onto the Hap particles exhibited a minor dependence on the L-p This protein adsorption behavior observed in,he present paper provided a definitive evidence that the C sites exposed on ac or bc crystal faces are the adsorption sites for BSA. (C) 2002 Elsevier Science B.V. All rights reserved.

The effect of polyvinyl alcohol (PVA) on the formation of spherical hematite particles from a forced hydrolysis reaction of acidic FeCl3 solution was examined. With increasing the PVA concentration, the shape of hematite particles was varied from spherical to disk-like by reducing their thickness. TEM and SEM observations clearly revealed that the disk-like hematite particles with average diameters of ca. 500 nm and aspect ratios of about 2 are consisting of aggregated cluster particles with a diameter of ca. 5-10 nm. The hematite particles formed with PVA were hydrohematite with a crystal lattice distortion and exhibited a polycrystalline nature. These particles changed from microporous to mesoporous after elimination of residual PVA molecules adsorbing on cluster particles by evacuating the samples above 300degreesC. This result supports the fact that hematite particles produced by the forced hydrolysis reaction are aggregates, as we further revealed recently by using simultaneous temperature programmed desorption, mass spectroscopy and thermogravimetric measurements (Phys. Chem. Chem. Phys., 2001, 3, 2949). It was suggested that the large voids between the cluster particles filled with PVA molecules within the disk-like particles produce mesopores after eliminating the PVA molecules.

The deuteration of synthetic calcium hydroxyapatite (CaHap) and the effect of fluoridation on the deuteration were investigated by in situ Fourier transform infrared spectroscopy to elucidate the surface structure of CaHap particles. The deuteration of column OH- ions of CaHap was reduced by the fluoridation, indicating that the deuteration does not happen in the columns of which the entrance is closed with F- ions replacing OH- ions. The 2680-cm(-1) band observed on the deuterated CaHap was assigned to the surface OD- ions which react with CO2 molecules. The 2633-cm(-1) band due to the column OD- ions was not influenced by CO2 adsorption. The fluoridated CaHap did not give rise to the surface OD- band, because the surface OH- ions were replaced with F-.

The roles of metal (Me) ions (Cu(II) and Cr(III)) in the morphologies and structures of hematite particles, produced from a forced hydrolysis reaction of FeCl3-HCl at various concentrations of metal ions ranging from 0 to 0.8 in the Me/(Fe + Me) atomic ratio (X-Me), were investigated by separation of the reaction into two steps: precipitation of beta-FeOOH and phase transformation from beta-FeOOH to hematite. The metal ions inhibited the particle growth of beta-FeOOH at a lower concentration region, while they promoted the particle growth at a higher concentration region with incorporation of these ions into the crystal lattice. The beta-FeOOH particles produced with metal ions exhibited high specific surface areas and microporosities. It was suggested that the phase transformation from beta-FeOOH to hematite is strongly affected by the metal ions incorporated into beta-FeOOH particles but not by those adsorbed on the particle surface.