Hydroxyapatite synthesised from nanosized calcium carbonate via hydrothermal method (original) (raw)
Related papers
Hydrothermal synthesis and nanostructure of carbonated calcium hydroxyapatite
Journal of Materials Science-materials in Medicine, 2006
The influence of precursor concentration, pressure, temperature and time of hydrothermal synthesis on the development of calcium hydroxyapatite structure has been analyzed. The obtained results show that it is possible to adjust the conditions of hydrothermal synthesis from solutions of relatively high concentrations to obtain calcium hydroxyapatite nanopowders of well-defined structure. The relationship between the synthesis and the lattice parameters, as well as the crystallite size and the microstructure of synthesized hydroxyapatite has been established. The synthesized powders are preferentially carbonated hydroxyapatite of the B type in the form of agglomerates that accommodate two-modal size pores of 1.5–10 and 50–200 nm. The structure of calcium hydroxyapatite particles consists of crystallites 8–22 nm in size, bound within prime particles, which size is between 10 and 63 nm, that in turn form bigger agglomerates 200 nm in size, which further cluster building up agglomerates 5–20 μm in size.
Materials Science and Engineering: B, 2012
The synthesis of calcium hydroxyapatite (Ca-HA) starting from calcium carbonate and different orthophosphate sources, including orthophosphoric acid, potassium, sodium and ammonium dihydrogen orthophosphates, was investigated under ambient conditions. The reaction started with calcium carbonate dissolution in an acid medium, followed by rapid precipitation of calcium cations with orthophosphate species to form calcium phosphate based particles which were in the size range of 0.4-1 m. These particles then agglomerated into much larger ones, up to 350 m in diameter (aggregates). These aggregates possessed an unstable porous structure which was responsible for the porosity of the final products. The highest specific surface area and pore volume were obtained with potassium dihydrogen orthophosphate. On the other hand, orthophosphoric acid led to the highest dissolution of calcium carbonate and the complete precipitation of orthophosphate species. Under ambient conditions, calcium phosphate based solid products of low crystallinity were formed. Different intermediates were identified and a reaction pathway proposed.
Revista Romana de materiale = Romanian journal of materials = RRM
În această lucrare este prezentată o metodă de sinteză a unui biomaterial ceramic de tipul hidroxiapatitei, Ca 10 (PO 4 ) 6 (OH) 2 , componentul mineral al ţesuturilor dure din organismele vii. Pulberile de hidroxiapatită au fost obţinute prin metoda de coprecipitare chimică, prin utilizarea hidroxidului de calciu şi a acidului ortofosforic ca surse de calciu şi fosfor. Pulberile obţinute au fost caracterizate prin intermediul difracţiei de raze X, metodei de difuzie dinamică a luminii (DLS) şi a microscopiei electronice cu baleiaj (SEM). Metoda propusă a condus la obţinerea unei hidroxiapatite cu o cristalinitate mai mare de 80%, în cazul tuturor probelor tratate termic la 800 0 C.
Synthesis of hydroxyapatite by hydrolysis of α-Ca3(PO4)2
Russian Chemical Bulletin, 2005
Conditions for hydroxyapatite (HAP) synthesis in aqueous solutions by hydrolysis of α Са 3 (РО 4) 2 were studied. Temperature exerts a substantial effect on the rate of α Ca 3 (PO 4) 2 hydrolysis and also changes the morphology of the reaction products. At 40 °C, the plate like intersecting (perpendicular to the surface of the initial particles) crystals of HAP grow. Their maximum size after the 24 h hydrolysis is 1-2 µm. Needle like HAP crystals are formed upon boiling of the suspension. The morphology observed for the HAP particles agrees well with the conclusions obtained by analysis of the kinetics of tricalcium phosphate hydrolysis.
Journal of Materials Science & Technology, 2013
The syntheses of nanosized carbonated hydroxyapatite (CHA) were performed by comparing dropwise and direct pouring of acetone solution of Ca(NO 3) 2 $4H 2 O into mixture of (NH 4) 2 HPO 4 and NH 4 HCO 3 at room temperature controlled at pH 11. Direct pouring method was later applied to study the increment of carbonate content in syntheses. The as-synthesized powders were characterized by various characterization techniques. The crystallographic results of the produced powders were obtained from X-ray diffraction analysis, whilst the carbonate content in the produced powders was determined by the CHNS/O elemental analyzer. Fourier transform infrared analysis confirmed that the CHA powders formed were B-type. Field emission scanning electron microscopy revealed that the powders were highly agglomerated in nanosized range and hence energy filtered transmission electron microscopy was employed to show elongated particles which decreased with increasing carbonate content.
Journal of the American Ceramic Society, 2006
Hydroxyapatite (HAp: Ca 10 (PO 4 ) 6 (OH) 2 ) was synthesized by aqueous precipitation using CaCl 2 and Na 3 PO 4 with NaOH added to ensure completion of the reaction at room temperature. The HAp powder prepared using stoichiometric amounts of NaOH was stable even at 12001C, but the HAp prepared with sub-stoichiometric amounts of NaOH resulted in its transformation into b-tricalcium phosphate at 6001C. The reaction pH, X-ray diffraction, thermal analysis, scanning electron microscopy, Fourier transform infrared analyses and inductively coupled plasma-optical emission spectroscopy were used to characterize the phase purity, thermal stability, morphology, and chemical composition of the synthesized HAp powder.
IOSR Journal of Applied Chemistry, 2014
Hydroxyapatite Ca 10 (PO4) 6 (OH) 2 (HA) is an important biomaterial and is the principal inorganic constituent of bones and teeth. It is also used as implant in the human body. By this investigation, hydroxyapatite nanostructured (18-56 nm) powders were prepared using novel wet precipitation method with calcium hydroxide and orthophosphoric acid solution as calcium and phosphorus precursors respectively. The Ca/P molar ratios of initial reagents are equal to 2.5. The HA filtered was dried at 90°C and calcined to different temperatures (300-1000°C). X-ray diffraction and Fourier transform infra-red spectroscopy used to characterize the calcined powder. The calcination reveals HA nano-powders. The particle size and crystallinity increase with the temperature. We note the formation of CaO at 1000°C. The refinement of cells parameters was performed by Fullprof-suite program. Thermal analysis (TG-DTA) was carried out to investigate the thermal stability of the powder.
A novel hydrothermal synthesis of nanohydroxyapatite from eggshell-calcium-oxide precursors
Heliyon, 2020
Hydroxyapatite (HA) is a material that has been widely applied to replace the damaged bone as a bone implant. Different types of HA have been successfully synthesized by a hydrothermal method based on calcium oxide (CaO) which was originated from chicken eggshells and diammonium hydrogen phosphate (DHP)/(NH 4) 2 HPO 4 as their precursors. We present a novel approach to the hydrothermal synthesis of HA form eggshells as a new precursor via a one-step synthesis method. The influence of temperature was also observed to study the effect on the crystallinity, purity, and morphology of obtained HAs. The synthesis was carried out at two different temperatures, 200 C (HA-200) and 230 C (HA-230) for 48 h respectively. The structures, purities, and morphologies of hydroxyapatite were analyzed by X-ray Diffraction (XRD), Fourier Transform Infra-Red (FTIR), and Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS), and Transmission electron microscopy (TEM). The XRD patterns show the HA main phase indicated the purity of 96.5% for HA-200 and 99.5% for HA-230. The TEM micrograph suggested a hexagonal-like of HA with an average particle size of 92.61 nm. Hexagonal-like of HAs are suitable for bone implants and further application.
Nanomaterials
Biogenic calcium carbonates naturally contain ions that can be beneficial for bone regeneration and therefore are attractive resources for the production of bioactive calcium phosphates. In the present work, cuttlefish bones, mussel shells, chicken eggshells and bioinspired amorphous calcium carbonate were used to synthesize hydroxyapatite nano-powders which were consolidated into cylindrical pellets by uniaxial pressing and sintering 800–1100 °C. Mineralogical, structural and chemical composition were studied by SEM, XRD, inductively coupled plasma/optical emission spectroscopy (ICP/OES). The results show that the phase composition of the sintered materials depends on the Ca/P molar ratio and on the specific CaCO3 source, very likely associated with the presence of some doping elements like Mg2+ in eggshell and Sr2+ in cuttlebone. Different CaCO3 sources also resulted in variable densification and sintering temperature. Preliminary in vitro tests were carried out (by the LDH assay)...
Synthesis and Characterization of Thermally Stable Hydroxyapatite
Annales De Chimie-science Des Materiaux, 2021
Nanocrystalline and thermally stable hydroxyapatite (HA) powder with nominal composition of Ca10(PO4)6(OH)2 was prepared by wet chemical route from calcium hydroxide Ca(OH)6 and mono ammonium phosphate NH4H2PO4 as calcium and phosphate sources, respectively. The effect of calcination temperature on the structure, microstructure, molecular bonding, thermal behavior and morphology was investigated by X-ray diffraction patterns (XRD), Fourier Transform Infra-Red (FT-IR), Raman spectroscopy, thermogravimetry (TGA), differential thermal analysis (DTA) and scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS) analysis. The XRD patterns of the as-prepared and calcined powders exhibit a single phase of hydroxyapatite. The crystallite size of as-prepared and calcined HA is in the range of 44−182 nm. FT-IR and Raman spectroscopy results are in good agreement with XRD ones. The EDS analysis reveals the presence of all elements. The thermal stability of the synthesized powders is evidenced by TGA/DTA scans which show a weight loss smaller than 2%.