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1.
In order to develop new bioactive calcium phosphate (CaP) materials to repair bone defects, it is important to ensure these materials more closely mimic the non-stoichiometric nature of biological hydroxyapatite (HA). Typically, biological HA combines various CaP phases with different impurity ions, which substitute within the HA lattice, including strontium (Sr2+), zinc (Zn2+), magnesium (Mg2+), carbonate (CO32-) and fluoride (F-), but to name a few. In addition to this biological HA have dimensions in the nanometre (nm) range, usually 60?nm in length by 5–20?nm wide. Both the effects of ion substitution and the nano-size crystals are seen as important factors for enhancing their potential biofunctionality. The driving hypothesis was to successfully synthesise nanoscale hydroxyapatite (nHA), co-substituted with strontium (Sr2+) and zinc (Zn2+) ions in varying concentrations using an aqueous precipitation method and to understand their chemical and physical properties. The materials were characterised using Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), X-Ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM) techniques. The FTIR, XRD and XPS results confirmed that the nHA was successfully co-substituted with Sr2+ and Zn2+, replacing Ca2+ within the nHA lattice at varying concentrations. The FTIR results confirmed that all of the samples were carbonated, with a significant loss of hydroxylation as a consequence of the incorporation of Sr2+ and Zn2+ into the nHA lattice. The TEM results showed that each sample produced was nano-sized, with the Sr/Zn-10%nHA having the smallest sized crystals approximately 17.6 ± 3.3?nm long and 10.2 ± 1.4?nm wide. None of the materials synthesised here in this study contained any other impurity CaP phases. Therefore, this study has shown that co-substituted nHA can be prepared, and that the degree of substitution (and the substituting ion) can have a profound effect on the attendant materials’ properties.  相似文献   

2.
The incorporation of therapeutic ions like Sr2+, Si4+, Zn2+ and Li+ into biomaterials has become a promising approach to promote bone regeneration. However, the effects of Sr2+ and Zn2+ co-substitution on the crystal structure and properties of β-tricalcium phosphate (β-TCP) have not been elucidated well. In this study, Sr2+/Zn2+ co-substituted β-tricalcium phosphate (SrZnTCP) nano-powders with different extents of substitution (0–4.8 mol%) were synthesized by poly(ethylene glycol)-assisted co-precipitation and subsequent heat treatment. The as-synthesized SrZnTCP nano-powders were characterized by x-ray diffraction, Fourier transform infrared spectroscopy, elemental analysis, Rietveld refinement and differential scanning calorimetry. The results showed that the conversion of calcium-deficient apatite to β-TCP was achieved after heat-treatment above 800 °C. The a-axis and c-axis lattice parameters gradually decreased with increasing level of Sr2+/Zn2+ co-substitution in β-TCP lattice. Sr2+ and Zn2+ preferentially occupied the ninefold coordinated Ca (4) sites and the sixfold coordinated Ca (5) sites, respectively. The co-substitution of Sr2+ and Zn2+ for Ca2+ significantly improved the thermal stability of β-TCP. The release rate of Zn2+ from SrZnTCP depended on Ca2+ concentration over 63-day immersion in PBS solution while that of Sr2+ was not affected by Ca2+ concentration. The amount of Sr2+ released increased with increasing Sr2+ content in SrZnTCP. Collectively, SrZnTCP showed great promise as a Sr2+/Zn2+-releasing biomaterial for bone repair, although no obvious mineralization was observed on β-TCP and SrZnTCP disc samples during 56 days of immersion in simulated body fluid.  相似文献   

3.
《Ceramics International》2017,43(12):9084-9091
This paper reports the preparation of Eu3+ doped Gadolinium oxyorthosilicate (Gd2SiO5:Eu3+) phosphor with different concentration of Eu3+(0.1–2.5 mol%) using the modified solid state reaction method. The synthesis procedure of the Gd2SiO5:Eu3+phosphor using inorganic materials such as Gd2O3, silicon dioxide (SiO2), europium oxide (Eu2O3) and boric acid (H3BO3) as flux is discussed in detail. The prepared phosphor samples were characterized by using X-Ray Diffraction (XRD), Field Emission Gun Scanning Electron Microscopy (FEGSEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), Photoluminescence (PL) and Thermoluminescence (TL). The Commission Internationale de l′Eclairage(CIE) coordinates were also calculated. The PL emission was observed in the 350–630 nm range for the Gd2SiO5:Eu3+ phosphor. PL excitation peaks were observed at 266, 275, 312 and 395 nm while the emission peaks were observed at 380, 416, 437, 545, 579, 589, 607, 615 and 628 nm. The emission peak at 615 nm was the most intense peak for all the different Eu3+ concentration samples. From the XRD data, using the Scherrer's formula, the average crystallite size of the Gd2SiO5:Eu3+ phosphor was calculated to be 33 nm. TL was carried out for the phosphor after both UV and gamma irradiation. The TL response of the Gd2SiO5:Eu3+ phosphor for the two different radiations was compared and studied in detail. It was found that the present phosphor can acts as a single host for red emission (1.5 mol%) for display devices and light emitting diode (LED) and white light emission for Eu3+(0.1 mol%) and it might be used as a TL dosimetric material for gamma dose detection.  相似文献   

4.
Eu2+, Mn2+ doped Sr1.7Mg0.3SiO4 phosphors were prepared by high temperature solid-state reaction method. Their luminescence properties were studied. The emission spectra of Eu2+ singly doped Sr1.7Mg0.3SiO4 consist of a blue band (455 nm) and a green band (550 nm). The relative intensities of two emissions varied with Eu2+ concentration. Eu2+ and Mn2+ co-doped Sr1.7Mg0.3SiO4 phosphors emit three color lights and present whitish color. The blue (455 nm) and green (550 nm) emissions are attributed to the transitions of Eu2+, while the red (670 nm) emission is originated from the transition of Mn2+ ion. The results indicate the energy transfer from Eu2+ to Mn2+. The mechanism of the energy transfer is resonance-type energy transfer due to the spectral overlap between the emission of Eu2+and the absorption of Mn2+.  相似文献   

5.
《Ceramics International》2017,43(11):8497-8501
Single-component white-emitting Sr3Y(PO4)3:Dy3+ phosphors were synthesized by a high-energy deformation process. X-ray diffraction patterns showed the resulting crystallized phase to be of cubic structure, space group I-43d (no. 220). The broad-band excitation spectra between 250 and 500 nm were observed by monitoring the emission wavelength at 576 nm, which matches well with commercial near-UV or blue LED chips. Under a 352 nm excitation, the emission peaks were observed at 483 nm (blue), 576 nm (yellow), and 666 nm (red), corresponding to the 4F9/26H15/2, 4F9/26H13/2, and 4F9/26H11/2 transitions of Dy3+ ions. The optimized doping concentration of Dy3+ ion was 8 mol%. By controlling the Dy3+ ion concentration, tunable colors from white to yellow were obtained in Sr3Y(PO4)3:Dy3+ phosphors. These results reveal that studied materials may be a promising candidate for white LED applications.  相似文献   

6.
《Ceramics International》2017,43(13):9860-9871
A brick clay mixture from a company localized in the north west of France is used for this study. The feasibility of producing geopolymer materials from a clay mixture was investigated. The final aim is to find a new application for this aluminosilicate material. One metakaolin (for a reference), the brick clay mixture, and the clay mixture calcined at two temperatures were compared after reaction with each of three alkaline solutions with different reactivity (the reactivity of each is defined). Physical, chemical, structural (FTIR and XRD) and thermal characterization (DTA) were first performed on the raw materials. Then, the structural evolution of the formed geopolymers was investigated using FTIR spectroscopy and XRD. Thus, this study demonstrates the feasibility of producing consolidated materials from a calcined brick clay (containing calcium oxides), which exhibits higher reactivity than brick clay. Plus, from a mixture of 25 wt% of less reactive materials such as ground brick clay and 75 wt% of reactive materials, it is possible to obtain geopolymer materials. FTIR study reveals the presence of a Ca2+ release phenomena, with a simultaneous polycondensation reaction for products based on calcined brick clay, which is different according to the silicate solution. Moreover, a link between [M++M2+] and the different networks formed in the samples based on calcined clay was found. Indeed, it appears that the concentration within the range 10.5–14 mol/l favors the geopolymer network formation.  相似文献   

7.
A series of red-emitting phosphors Eu3+-doped Sr3Y(PO4)3 have been successfully synthesized by conventional solid-state reaction, and its photoluminescence properties have been investigated. The excitation spectra reveal strong excitation bands at 392 nm, which match well with the popular emissions from near-UV light-emitting diode chips. The emission spectra of Sr3Y(PO4)3:Eu3+ phosphors exhibit peaks associated with the 5D0  7FJ (J = 0, 1, 2, 3, 4) transitions of Eu3+ and have dominating emission peak at 612 nm under 392 nm excitation. The integral intensity of the emission spectra of Sr3Y0.94(PO4)3:0.06Eu3+ phosphors excited at 392 nm is about 3.4 times higher than that of Y2O3:Eu3+ commercial red phosphor. The Commission Internationale de l’Eclairage chromaticity coordinates, the quantum efficiencies and decay times of the phosphors excited under 392 nm are also investigated. The experimental results indicate that the Eu3+-doped Sr3Y(PO4)3 phosphors are promising red-emitting phosphors pumped by near-UV light.  相似文献   

8.
《Ceramics International》2017,43(11):8306-8313
New glassy materials in the system xCuO-(50-x) CdO–50B2O3 were prepared by a melting-quench technique. Their UV–vis, FTIR, electrical, dielectric, SEM, XRD patterns and density properties were investigated. SEM and XRD studies confirmed their amorphous nature and the presence of crystalline phases in the sample with 50 mol% CuO. Replacing CdO with increasing concentrations of CuO decreased the density and increased the molar volume. Optical reflectance spectra revealed the presence of Cu2+ ions in octahedral coordination, as well as the presence of Cu1+ and Cuº in the samples with greater than 30% CuO. FTIR measurements confirmed the conversion of BO4 units to BO3 units with increasing CuO contents. The conduction in the CuO-containing samples increased as the CdO was completely replaced by CuO. The CuO-containing samples exhibited a slight increase in the ɛʹ values with increasing temperature and a decrease with increasing frequency. The ɛʹ values gradually increase upon replacing CdO with up to 40 mol% CuO. An abrupt increase in ɛʹ was recorded for the sample with 50 mol% CuO, particularly at high temperature. The latter sample showed an εʹ value of 927at 100 Hz and 298 K. Prepared samples with high ɛʹ values are promising candidates for capacitor materials in electronic devices.  相似文献   

9.
《Ceramics International》2017,43(14):11244-11249
Sr3(PO4)2:Re3+, Li+ (Re = Eu, Sm) red phosphors were prepared via a high temperature solid state reaction, and their structure and luminescence properties were investigated. X-ray diffraction patterns indicate that the phase of as-prepared samples is in good agreement with standard Sr3(PO4)2 structure. Under 395 nm excitation, the emission of Sr3(PO4)2:Eu3+ consists of a strong peak centered at 622 nm and two weak peaks centered at 598 nm and 660 nm, which correspond to 5D07F2, 5D07F1 and 5D07F3 transitions, respectively. Also, the emission spectrum of Sr3(PO4)2:Sm3+ shows three main peaks at 568 nm, 603 nm and 651 nm, which are attributed to 4G5/26HI/2 (I = 5, 7, 9) transitions of Sm3+. Furthermore, luminescence properties of Sr3(PO4)2:Re3+, Li+ (Re = Eu, Sm) samples are enhanced significantly by Li+ ions doping as charge compensator. Results indicate that as-prepared Sr3(PO4)2:Re3+, Li+ (Re = Eu, Sm) could be the potential red phosphors used in white light-emitting diodes.  相似文献   

10.
Chelating EDTA-based bichromophores, 1,4-bis(methylenecarboxy)-1,4-bis(N-1-naphthylmethylacetamide)-1,4- diazabutane (1) and its 2-napthyl isomer (2), were synthesized, and their fluorescence emission and complexation with Cd2+ and Zn2+ were studied. The fluorescence spectrum of 2 exhibited an emission band due to intramolecular excimer at about 400 nm in addition to a band from a monomeric (or isolated) chromophore at 335 nm. Complexation with Cd2+ sensitively intensified the excimer band and weakened the monomer band, as a result of formation of a [CdL2]2− type complex. In contrast, Zn2+ formed [ZnL]0, leading to depression of the excimer emission and enhancement of the monomer emission. The extent of the changes in emission intensities in the Cd2+ complex was larger than that of the Zn2+ complex contrary to the common metal-ion effect on fluorescence. Such a characteristic emission property was not observed for isomer 1. Ligand 2 has the high Cd-sensing capability that originates from monomer–excimer interconversion.  相似文献   

11.
12.
To synthesize various complex oxide materials and their solid solutions, we applied a novel “melt-synthesis technique” rather than conventional solid-state reaction techniques. Rapid synthesis methods to develop those double oxides have been strongly anticipated. During melt synthesis, the mixture of oxides or their precursors is melted rapidly (1–60 s) in an arc-imaging furnace using strong light radiation. A spherical molten sample with multiple homogeneously mixed cations was solidified directly on a copper hearth with rapid cooling of ca. 102 °C/s.We studied the synthesis of A2BO4 type double oxides (AA′)2BO4 (A = Sr2+, Ca2+, A′ = La3+, Gd3+, Y3+, Eu3+, B = Al) using this method. Homogeneous samples with Eu3+ dopants were synthesized using liquid phase mixing in a few seconds, which is much faster than diffusions of ions in solid phase. Red fluorescence under the irradiation of ultraviolet light (254 and 365 nm) was observed. The excitation band shifted.  相似文献   

13.
Sorption of Cd(II), Ni(II) and U(VI) ions onto a novel cast PVA/TiO2/APTES nanohybrid adsorbent with variations in adsorbent dose, pH, contact time, initial metal concentration and temperature has been investigated. The adsorbent were characterized by SEM and FTIR analysis. BET surface area, pore diameter and pore volume of adsorbent were 35.98 m2 g−1, 3.08 nm and 0.059 cm3 g−1, respectively. The kinetic and equilibrium data were accurately described by the double-exponential and Freundlich models for all metals. The maximum sorption capacities were 49.0, 13.1 and 36.1 mg g−1 for Cd(II), Ni(II) and U(VI) ions with pH of 5.5, 5 and 4.5, respectively. Thermodynamic studies showed that the sorption process was favored at higher temperature. The adsorbent can be easily regenerated after 5 cycles of sorption–desorption.  相似文献   

14.
《Ceramics International》2016,42(9):10579-10586
Bulk and thin film forms of titanium dioxide (TiO2) have been studied many times due to its very promising optical properties. In this study, low-cost flame spray pyrolysis (FSP) synthesis of Nd3+/Er3+doped TiO2 nanoparticles has been reported for the first time. The produced particles were post-annealed after FSP process at 550 °C in order to obtain crystalline structure. The phase and elemental analysis of the produced materials were performed by X-Ray Diffraction (XRD) and X-Ray Photoelectron Spectroscopy (XPS), respectively. The surface morphology, accurate size and specific surface area of the primary particles were identified using scanning electron microscopy (SEM) and particle size analyser. Luminescent properties of the produced nanoparticles were investigated by steady state and time resolved fluorescence spectra. Doping of TiO2 nanoparticles with the rare earths of Nd3+and Er3+resulted in visible and near-infrared light emission when excited at 364 nm. The utilized nanoparticles yielded bi-and tri-exponential decay curves. Additionally, they exhibited typical upconversion luminescence when radiated by 810 nm.  相似文献   

15.
16.
SBA-15 functionalized with 3-aminopropyltrimethoxy-silane was studied as potential absorbent for Cd2+, Co2+, Cu2+, Zn2+, Pb2+, Ni2+, Al3+ and Cr3+. The adsorption capacity and selectivity of the materials were investigated in single and multi-metal solutions. Using single-metal solutions, the adsorbent was found to have an affinity (molar basis) for metal ions in decreasing order of Al3+ > Cu2+ > Ni2+ > Zn2+ > Co2+ > Cd2+ > Pb2+ > Cr3+. Using very dilute solutions, i.e., 10 ppm, more than 95% of cations were removed, except Co2+ and Cr3+, indicating the high sensitivity of the current adsorbent. The affinity for coexisting metal cations decreased in the order of Al3+ > Ni2+ > Cr3+ > Pb2+ > Zn2+ > Cd2+ > Co2+ > Cu2+. The adsorption capacities in multi-metal solutions were lower than in single-metal ones because of competition between metallic elements for the amine groups, with a preference for Al3+. The amine-modified SBA-15 adsorbent exhibited an excellent selectivity against sodium, potassium, and calcium, indicating that the ionic strength does not affect the adsorption properties. Application of this material to remove copper in tap water, river water, and electroplating wastewater was shown to be successful.  相似文献   

17.
Ba2Zn(1+x)Si2O(7+x) ceramics were prepared using the conventional solid-state method at 1200 °C for 3 h in air. Apart from the previously reported Ba2Zn(1+x)Si2O(7+x) (x = 0) with a monoclinic structure (C 2/c), the end-member compositions at x = −1 and 1 exhibit single-phase β-BaSiO3 with an orthorhombic structure (P212121) and BaZnSiO4 with a hexagonal structure (P63), and possess a coexistence of weak ferroelectricity and low-permittivity microwave dielectric properties. A reduction in Zn2+ content mainly decreases the intensity of the εr anomaly peak at lower temperature and increases the εr (or frequency) stability against temperature. The Zn2+-rich BaZnSiO4 phase has a τf value of −181 ppm/°C, whereas the τf value of Zn2+-free BaSiO3 phase decreases to −35.4 ppm/°C. The Zn2+ deficiency in Ba2ZnSi2O7 composition could inhibit the presence of BaZnSiO4 phase and improve the τf value, whereas excessive Zn2+ cations prompt the formation of the BaZnSiO4 phase to deteriorate significantly the τf value.  相似文献   

18.
《Ceramics International》2016,42(13):14956-14962
SrxCa1−xAlSiN3: Eu2+ phosphors were prepared by using the high temperature solid state reaction in a 1.1 Mpa N2 atmosphere. The phase structures, photoluminescence (PL) properties, and chromaticity properties of the phosphors affected by Sr/Ca Substitution have been investigated in detail. With increasing Sr content (x value), the crystal grain became bigger and the average grain size increased from 5 µm to 10 µm. PL emission bands of SrxCa1−xAlSiN3: Eu2+ showed a blue-shift from 660 (x=0) to 617 nm (x=0.8), the shoulder of the excitation spectra around 550 nm showed a slightly blue-shift and decay lifetime shortened from 776.96 (x=0.2) to 642.35 ns (x=0.8). Both the emission and excitation intensity of peak position increased with Sr content increased. The ideal white light with high CRI (Ra>88) can be obtained by mixing the SrxCa1−xAlSiN3: Eu2+ phosphors and commercial green phosphors with appropriate proportion of the components.  相似文献   

19.
《Ceramics International》2016,42(3):4080-4089
The influences of PZN content and Sr2+ substitution on the structure and electrical properties of Pb(Zn1/3Nb2/3)O3–Pb(Ni1/3Nb2/3)O3–Pb(Zr0.52Ti0.48)O3 (abbreviated as PZN–PNN–PZT) piezoelectric ceramics were studied. All as-prepared PZN–PNN–PZT ceramics presented single phase of perovskite structure, while higher PZN contents favored rhombohedral symmetry and larger grain size. Meanwhile, with the increase in Sr2+ content, the phase structure changed from a mix of tetragonal and rhombohedral symmetries to a pure rhombohedral symmetry. Although the ferroelectric Curie temperature (TC) was decreased with increasing the PZN and Sr2+ contents, the piezoelectric constant (d33) exhibited the opposite trend. As a result, optimum comprehensive electrical properties were obtained in the 0.1PZN–0.1PNN–0.8PZT composition with 10 mol% Sr2+ substitution: d33~800 pC/N, kp ~0.65, ɛr~4081, TC~176 °C, Pr~30.92 µC/cm2. Thus, the 10 mol% Sr2+-substituted 0.1PZN–0.1PNN–0.8PZT ceramic is a promising candidate for high performance applications.  相似文献   

20.
A reusable chelating fiber containing polyamino–polycarboxylic acid ligands was prepared via the stepwise modification of polyacrylonitrile fiber with diethylenetriamine and chloroacetic acid. The amination and carboxylmethylation conditions were optimized, and the modified fiber was characterized by elemental analysis, XRD, SEM and FTIR. For Cd2+ in water, this chelating fiber has prominent adsorption abilities such as low adsorption limitation (0.001 mg/L), high adsorption capacity (1.34 mmol/g) and fast response speed (half-saturation adsorption time less than 0.5 min based on 1 mg/mL Cd2+). The effectiveness of this chelating fiber has been proved by using it to treat actual sewage water, where the concentration of Cd2+ was reduced from 0.540 to below 0.001 mg/L. This level easily meets drinking water standards (0.003 mg/L) issued by the World Health Organization. Moreover, this chelating fiber is also very effective at treating other metal ions such as Cu2+, Ca2+, Zn2+, Mg2+, Pb2+, Ni2+, Ag+ and Hg2+.  相似文献   

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