Carbonate Hydroxylapatite Research Articles

Reverse flotation process in double stage on the Algerian phosphate ore treatment

Purpose. In this work, the influence of flotation reagents on the separation yield of the phosphate-carbonate system is studied. The investigation is conducted by the reverse flotation process in double stage of the phosphate ores from the Jebel Onk deposit-Algeria. Methodology. The experimental part can be divided into three aspects, a mechanical preparation of the samples, and flotation tests in the first stage followed by a double flotation and, finally, characterization of the flotation products by different physical-chemical analysis techniques. Findings. Reverse flotation double stage process was applied on two classes of phosphate ores (C1: 40–250 and C2: 250–500 m). The samples are constituted by phosphatic elements (apatite), cemented by a mixture of a great amount of dolomite with low amounts of quartz, clay and calcite. Flotation results showed that P2O5 recovery was higher for C2 compared to C1. Thus, oleic acid and double tartrate of sodium-potassium could be considered as the best reagent since the P2O5 recovery content corresponds to 29.27 and 31.25 % for C1 and C2, respectively. Compared to the oleic acid and pine oil reagent, the recoveries of P2O5 were 28.85 and 30.55 % for C1 and C2, respectively. However, when other reagents as (oleic acid  phosphoric acid) and (oleic acid + diesel fuel) were used, the recovered amount of P2O5 was found to be less important, 27.80 and 27.10 % for class C1, and 30.14 and 29.15 % for C2, respectively. Originality. During this study two main axes were discussed: the first one was the influence of flotation reagents on flotation of the first and second stages, the second one was to study the effect of grain size on the flotation yields. The flotation process has been shown to be effective both in terms of depressed phosphate elements in the phosphate concentrates and in gangue floated in the flotation tailings. It can be seen that the concentrate contents of around 32 % is achieved in P2O5 with superior recoveries of 99 %. Practical value. The results of analyses carried out on the flotation products showed, in most cases, that the streams are richer in phosphate elements (fluorapatite, carbonate hydroxylapatite, carbonate fluorapatite) and a low amount of carbonates (dolomite and calcite), unlike floating, mainly made up of dolomite with a small amount of phosphated elements.

Taxonomic status and geographic distribution of Phycogorgia fucata (Valenciennes 1846) (Octocorallia: Gorgoniidae)

ABSTRACT The octocoral research in Chile has been concentrated along the Patagonian coast; there are few reports about octocoral taxa living north of the fjord region. Although some species have been recorded and collected, the taxonomy is not clear and is in need of reappraisal. Herein we revisit the genus Phycogorgia. The original type material of the monospecific genus Phycogorgia was analysed in this study. Additional material was collected along the Chilean coast, and information on geographic distribution gathered, which reflects the limited biogeographic distribution of this genus throughout the eastern Pacific Ocean. Phycogorgia fucata is characterized by having conspicuous frondose, leaf-like branches which are wide, and strongly flattened; the axes are flat and expanded with carbonate hydroxylapatite mineralized fibres in the central core; the polyps are totally retractile in the coenenchyme in low polyp-mounds; the sclerites are basically capstans, and spindles. The species is re-described and a paratype is designated from the original type material of Valenciennes, establishing the species name correctly following the International Code of Zoological Nomenclature regulations. Phycogorgia fucata was found along the Chilean coast from Concepción to Valdivia, 29–40°S, biogeographically called the Intermediate Area, showing colony morphological variation.

Mechanical properties, microstructure and morphological properties of badger teeth

The structure, composition and mechanical properties of badger teeth were characterized. At the same time, the difference between badger teeth and human teeth were analyzed. The micrographs of samples showed that badger teeth contained two layers – that is, enamel and dentin. In contrast to hardness, it indicated that the enamel has a higher hardness than dentin, and both are higher than those of humans. Meanwhile, badger teeth have an obvious hardness difference in enamel and dentin. And the badger enamel has a significant anisotropy, the hardness and the elasticity modulus in the cross-section were higher than those in the axial section. Fourier-transform infrared spectroscopy tests show that both the enamel and dentin consisted of carbonate–hydroxylapatite and hydroxyapatite crystals. And X-ray powder diffraction tests show that both the crystal amounts and size of enamel tended to be higher than those of dentin. The water, organic matrix and biomineral of each species were determined by thermogravimetry. Dentin had higher contents of water, organic matrix and carbonate (CO3) than enamel. In the natural world, the mechanical properties of badger teeth are related to their microstructures and compositions, which potentially provide an inspiration for machinery and bionic designs.

Reasons of Pathologies of Yakutian Mammoths’ Tusks in Late Pleistocene by Data of Isotopic and Geochemical Investigations

Among the remnants of Late Pleistocene mammals collected on the coast of the Laptev Sea, there are the tusks of woolly mammoth (Mammuthus primigenius) with abnormalities. An analysis of the isotopic composition of carbon from their bone carbonate hydroxylapatite, as well as geochemical studies of the substance of such tusks (35 items, a total of 38 samples) by x-ray fluorescence method was conducted. Significant differences in the chemical composition of the tusks with abnormalities and “normal” tusks in such the elements as Sr, Mg, Si, Al, Mn, Fe, Zn, etc. were revealed. An attempt to express the obtained anomalies of the chemical composition in the terms adopted in the description of microelementoses was made. It was determined that most studied mammoths lived in the cold epochs, however, the pathology of the tusks were observed for animals living both in the cold and warm epochs of the Late Pleistocene. The causes of occurrence of pathologies probably were linked to different types of physiological disorders affecting the growth and development of the tusks and, possibly, with changes in the geochemical background influencing the population of woolly mammoth in the North of Yakutia.

Carbonate hydroxylapatite synthesis and crystallization on metallic implants

The work deals with the synthesis of carbonate hydroxylapatite from a prototype human synovial fluid. The process of carbonate hydroxylapatite crystallization on the alloys of different composition, roughness, and treatment techniques is studied. The quantitative characteristics measuring the efficiency of coating deposition by biomimetic synthesis from the model solution of human synovial fluid are calculated.

Mineralogical characterization of calcification in cardiovascular aortic atherosclerotic plaque: A case study

AbstractCalcification in cardiovascular aortic atherosclerotic plaque contains Ca-phosphate minerals. However, most research on cardiovascular calcification has focused on its physiological properties rather than its mineralogical features. In this present study, cardiovascular calcification was characterized by collecting samples from patients’ tissues and applying mineralogical techniques. Synchrotron radiation-based micro-X-ray diffraction showed the calcification had a similar structure to hydroxylapatite (HAp). Transmission electron microscopy showed some structurally HAp-like spherical particles with a diameter of ∼200 nm and acicular crystals ∼100 nm × ∼20 nm in size. Selected-area electron diffraction indicated that these mineral particles belonged to the hexagonal crystal system. Fourier-transform infrared (FTIR) spectroscopy showed three typical peaks at 1469 cm−1, 1455 cm−1and 1413 cm−1, indicating that the carbonate group in the calcification plaque substituted for a hydroxyl group to form B-type CHAp (Ca10(PO4,CO3)x(OH)y). The FTIR mapping results illustrated the intergrowth of calcification and organic tissues and the inhomogeneous substitution of phosphate by carbonate in the calcification area. X-ray absorption near-edge structure analysis affirmed that the chemical environments of Ca in the calcification were close to those in HAp. Based on these mineralogical characteristics, the calcification in plaque is identified as a mixture phase of HAp and B-type carbonate HAp, which is similar to the composition of bones.

Technical Note: An X-ray absorption method for the identification of calcium phosphate species using peak-height ratios

Abstract. X-ray absorption near edge structure (XANES) studies on calcium phosphate species (Ca-P) deal with marginal differences among subtle spectral features despite a hitherto missing systematic breakdown of these differences. Related fingerprinting approaches depend, therefore, on spectral libraries that are not validated against each other, incomplete and scattered among publications. This study compiled a comprehensive spectral library from published reference compound libraries in order to establish more clear-cut criteria for Ca-P determination by distinctive phosphorus K-edge XANES features. A specifically developed normalization method identified diagnostic spectral features in the compiled library, e.g. by uniform calculation of ratios between white-line and secondary peak heights. Post-processing of the spectra (n = 81) verified distinguishability among most but not all phases, which included hydroxylapatite (HAP), poorly crystalline HAP, amorphous HAP, fluorapatite, carbonate fluorapatite (CFAP), carbonate hydroxylapatite, β-tricalcium phosphate, octacalcium phosphate (OCP), brushite, monetite, monocalcium phosphate, amorphous calcium phosphate (ACP), anapaite, herderite, scholzite, messelite, whiteite and P on CaCO3. Particularly, peak-height ratios significantly improved analyte specificity, e.g. by supplementary breakdown into OCP and ACP. The spectral analysis also revealed Ca-P standards that were rarely investigated or inappropriately synthesized, and thus provides a basis for standard selection and synthesis. The method developed and resulting breakdown by species were subsequently tested on Ca-P spectra from studies on bone and sediment. The test indicated that bone material likely comprises only poorly crystalline apatite, which confirms direct nucleation of apatite in bone. This biological apatite formation is likely opposed to that of sedimentary apatite, which apparently forms by both direct nucleation and successive crystallization. Application of the method to μXANES spectra of sediment particles indicated authigenic apatite formation by an OCP precursor.

Structure, composition and morphology of bioactive titanate layer on porous titanium surfaces

A bioactive coating was produced on pore surfaces of porous titanium samples by an amendatory alkali-heat treatment method. Porous titanium was prepared by powder metallurgy and its porosity and average size were 45% and 135 μm, respectively. Coating morphology, coating structure and phase constituents were examined by SEM, XPS and XRD. It was found that a micro-network structure with sizes of <200 nm mainly composed of bioactive sodium titanate and rutile phases of TiO2 covered the interior and exterior of porous titanium cells, and redundant Ca ion was detected in the titanate layer. The concentration distribution of Ti, O, Ca and Na in the coating showed a compositional gradient from the intermediate layer toward the outer surface. These compositional gradients indicate that the coating bonded to Ti substrate without a distinct interface. After immersion into the SBF solution for 3 days, a bone-like carbonate–hydroxylapatite showing a good biocompatibility was detected on the coating surface. And the redundant Ca advanced the bioactivity of the coating. Thus, the present modification is expected to allow the use of the bioactive porous titanium as artificial bones even under load-bearing conditions.

DEPOSITIONAL ENVIRONMENT AND BONE DIAGENESIS OF THE MIO/PLIOCENE LANGEBAANWEG BONEBED, SOUTH AFRICA

Langebaanweg is a world renowned, richly fossiliferous Miocene/Pliocene bone assemblage on the West Coast of South Africa. Despite considerable palaeontological investigation of the biodiversity of the site, few studies have been conducted on the bone diagenesis. This study examines the petrography of fossil bones and teeth in relation to the host sediment matrix. The Langebaanweg bonebed is variably matrix- and clast-supported, containing abundant gravel-size bone and phosphorite clasts in a quartzose sand matrix with minor amounts of peloidal phosphate grains and kaolinitic clay. The bimodal size distribution of clasts and sand matrix indicates a mixture of beach, fluvial and aeolian sources, consistent with a riverine or aquifer-fed waterhole palaeoenvironment proximal to the sea. Both macro- and microfaunal bones exhibit a range of surface colours (cream/brown through dark orange/brown to black) indicative of secondary mineral precipitation (including manganese) and some show physical damage from trampling. Three phases of bone diagenesis are recognised; an early, rapid transformation of bone (bioapatite) to mineral carbonate hydroxylapatite, an apatite cementation phase and a single, late growth of infilling Mn-rich alteration material. Except for rare burnt bones, bones and teeth mostly preserve fine histological detail. Despite differences in secondary mineral burden and physical deformation (trampling), diagenesis is fairly uniform within the deposit. The excellent bone preservation, and the fact that the deposit has not been reworked is important for depositional models. The classic Palaeo-Berg River fluvial depositional model is challenged in this paper by an alternative possibility that the deposit was an aquifer-fed, near coastal waterhole.

Accessing Hunter-Gatherer site structures using Fourier transform infrared spectroscopy: applications at a Taltheilei settlement in the Canadian Sub-Arctic

The results of Fourier transform infrared spectroscopy on soils and caribou bone from a Taltheilei culture settlement in northern Canada contribute to developing micro-archaeological approaches suitable for locating and characterizing hearth and midden features on hunter-gatherer sites. A weak yet pervasive signal for montgomeryite was developed from the diagenesis of dispersed ash and caribou processing residues. Disordered calcite, carbonate hydroxylapatite, charcoal, and burned bone in two pit-house hearth deposits indicate that both wood and bone were used for fuel. Crystallinity indices and carbonate/phosphate ratios for bone indicate high intensity burning. These data, in tandem with the presence of semi-subterranean dwellings, demonstrate that this particular tundra-based encampment was occupied during cold seasons, a type of settlement behaviour previously unrecognized in the Taltheilei archaeological record. Our results confirm that Fourier transform infrared spectroscopy is an accessible, rapid, and cost effective means of discovering micro-archaeological evidence valuable for reconstructing hunter-gatherer site structures.

Impact of Carbonate Hydroxylapatite (CHAP) Addition on Bio-Hydrogen Production from Microwave Pretreated Sludge

In order to promote the hydrolysis and disintegration of waste sludge, the most logical approach is pretreatments to disrupt the microbial cells of sludge. After microwave pretreatments, the heavy metal which were toxicity to H2 production were released from waste sludge, and the increase rate was 10.6 (Cu), 5.5(Cd), 3.6(Zn) and 1.6 (Ni) times after pretreatment. Carbonate hydroxylapatite (CHAP) had high efficiency in heavy metal removal. In this study, the effect of heavy metal removal on bio-hydrogen production from microwave pretreated sludge using CHAP was evaluated. 0.53 g/gVSS CHAP addition could enhance the bio-hydrogen yield by 53.6% compared with control, and the lag time was 9 h. Dosages of CHAP couldinfluence the hydrolysis, fermentation type and hydrogen yield of pretreated sludge.

Adsorption Study of Carbonate Hydroxylapatite for Hexavalent Chromium Ion from Aqueous Solution at Different Carbon Content

The adsorption of Cr6+ from aqueous solution by carbonate hydroxylapatite (CHAP) with different carbon content synthesized by precipitation. The CHAP was characterized and analyzed by TEM、FTIR and XRD. And adsorption was effected by the pH value、CHAP usage、adsorption time and other factors. The results show that under certain conditons, adsorption capacity enhanced with the carbon content increasing.

Preparation and Characterization of Carbon Hydroxyapatite with Different Carbon Content

Carbonate hydroxylapatite (CHAP) with different carbon content synthesized by precipitation, As raw material to calcium nitrate、potassium phosphate、potassium carbonate, by changing the incorporation of potassium carbonate.The CHAP was characterized by XRD、TEM and FTIR. And through analysis compared structure and morphology of carbon hydroxyapatite with different carbon content.

Effect of environmental conditions on the sorption of radiocobalt from aqueous solution to treated eggshell as biosorbent

Carbonate hydroxylapatite (CHAP), prepared from eggshell waste, was used to remove 60Co(II) from aqueous solutions. The sorption of 60Co(II) on CHAP as a function of contact time, pH, ionic strength and foreign ions in the absence and presence of humic acid and fulvic acid under ambient conditions was studied. The sorption of 60Co(II) on CHAP was strongly dependent on pH and ionic strength. The thermodynamic parameters (ΔH 0, ΔS 0, ΔG 0) of 60Co(II) sorption on CHAP were calculated from the temperature-dependent sorption isotherms, and the results indicated that the sorption process of 60Co(II) on CHAP was endothermic and spontaneous. At low pH, the sorption of 60Co(II) was dominated by outer-sphere surface complexation and ion exchange with Na+/H+ on CHAP surfaces, whereas inner-sphere surface complexation was the main sorption mechanism at high pH. Experimental results also indicated that CHAP was a suitable low-cost adsorbent for pre-concentration and solidification of 60Co(II) from large volumes of aqueous solutions.

Iron Age hydraulic plaster from Tell es-Safi/Gath, Israel

Hydraulic plasters or mortars prior to the Roman period are rare. Here, we report the identification and characterization of 3000 year old (Iron Age) hydraulic plaster surfaces from the site of Tell es-Safi/Gath. This site, located in central Israel, was occupied almost continuously from prehistoric through modern times, and is identified as the Canaanite and Philistine city of Gath. A survey using an on-site Fourier transform infrared spectrometer (FTIR) identified the presence of amorphous silicates, in addition to calcite, in each of two superimposed plaster layers. This suite of minerals is characteristic of hydraulic plaster. An in-depth characterization of the plasters using FTIR, acid dissolution, X-ray fluorescence (XRF), X-ray powder diffractometry (pXRD), heating experiments and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (SEM–EDS), shows that special silicate-containing minerals were brought from some distance to the site in order to produce these plaster surfaces. We therefore conclude that the plasters were deliberately produced, and were not the result of a fortuitous addition of local silicate minerals. A layer of around 150 μm thick enriched in carbonate hydroxylapatite was found in both plaster surfaces, and the same mineral was identified by infrared spectrometry in the surrounding sediments. This suggests that organic materials were used on these surfaces. These surfaces are among the oldest hydraulic plasters known.

Mineralization behavior and interface properties of BG-PVA/bone composite implants in simulated body fluid

Due to the non-bioactivity and poor conjunction performance of present cartilage prostheses, the main work here is to develop the bioactive glass–polyvinyl alcohol hydrogel articular cartilage/bone (BG-PVA/bone) composite implants. The essential criterion for a biomaterial to bond with living bone is well-matched mechanical properties as well as biocompatibility and bioactivity. In vitro studies on the formation of a surface layer of carbonate hydroxyl apatite (HCA) and the corresponding variation of the properties of biomaterials are imperative for their clinical application. In this paper, the mineralization behavior and variation of the interface properties of BG-PVA/bone composites were studied in vitro by using simulated body fluid (SBF). The mineralization and HCA layer formed on the interface between the BG-PVA hydrogel and bone in SBF could provide the composites with bioactivity and firmer combination. The compression property, shear strength and interface morphology of BG-PVA/bone composite implants varying with the immersion time in SBF were characterized. Also, the influence laws of the immersion time, content of BG in the composites and aperture of bones to the mineralization behavior and interface properties were investigated. The good mineralization behavior and enhanced conjunction performance of BG-PVA/bone composites demonstrated that this kind of composite implant might be more appropriate cartilage replacements.

Calcium L2,3-edge XANES of carbonates, carbonate apatite, and oldhamite (CaS)

The local electronic structure and stereochemistry of calcite, aragonite, dolomite, ferroan dolomite, manganoan calcite, synthetic carbonate hydroxylapatite (CHAP), and CaS (synthetic oldhamite) have been studied using Ca L 2,3 -edge X-ray absorption near-edge structure (XANES) spectroscopy. The XANES spectra of the calcite- and dolomite-structure carbonates are identical within error of measurement, confirming the local nature of X-ray absorption at the L 2,3 edge of Ca 2+ . The Ca L 2,3 -edge XANES spectrum of aragonite is distinct and indicates a weak crystal-field splitting of positive 10 Dq . Separate Ca1 and Ca2 sites are resolved in the XANES of hydroxylapatite and CHAP: Ca1 appears to have a very weak crystal field of negative 10 Dq , and Ca2 has a weak crystal field of positive 10 Dq . The Ca L 2,3 -edge XANES spectrum of CaS reflects both Ca and S unoccupied 3 d states, and is used to show progressive oxidation of the sulfide on exposure to air. The L 2,3 X-ray absorption edge of 3 d 0 cations is associated with the 2 p 5 3 d 1 excited electronic state. It is, therefore, a novel technique for studying the crystal field of K + , Ca 2+ , Sc 3+ , and Ti 4+ , which do not have populated 3 d orbitals in their ground state.

Study on Adsorption Characteristic of Carbonate Hydroxylapatite for Cu2+ from Aqueous Solution at Different Ca/P Ration

Study on Adsorption Characteristic of Carbonate Hydroxylapatite for Cu2+ from Aqueous Solution at Different Ca/P Ration

Bone diagenesis: New data from infrared spectroscopy and X-ray diffraction

This paper combines non-destructive high-resolution Fourier transform infrared spectroscopic techniques (attenuated total reflectance in the mid-infrared — ATR, and diffuse reflectance in the near-infrared — NIR) with X-ray diffraction and Rietveld analysis, in the study of bone diagenesis. Sixty fossil bones from two Upper Miocene sites in Greece (Pikermi and Chalkoutsi) and one Upper Pleistocene site in Cyprus (Aghia Napa) are investigated in comparison to various mineral and biological apatites. Diagenetic trends, common to all these sites include a subtle but systematic decrease of the unit cell volume and a-axis of carbonate hydroxylapatite, as well as a parallel increase of the coherence length along the c-axis. Chemometric modelling reveals that the changes in the unit cell and the coherence length are highly correlated to (and can be predicted on the basis of) the ATR spectra. Besides using chemometrics as a convenient predictive tool, we have been able to identify that the correlation with the XRD data is primarily based on the intensity of infrared bands at 577, 865 and 1092 cm − 1 , as well as on the position of the ν 1 phosphate mode at ca. 960 cm − 1 . These structural changes constitute the vibrational signature of diagenesis throughout our set of bone samples and can be accounted for by the stabilization of a distorted CO 3 2− species in the B-sites of apatite, and to a lesser extent by the substitution of OH − by F −. NIR spectroscopy allowed for the identification of a well-defined H 2O species, absorbing at 5318 and 7240 cm − 1 . This species is labile, appears to characterize mostly biogenic apatite, and is therefore considered to be chemisorbed on the surface of the crystallites.

Solid-State NMR Study of the Role of H and Na in AB-Type Carbonate Hydroxylapatite

Solid-state nuclear magnetic resonance (NMR) techniques, combined with Fourier transform infrared (FT-IR) spectroscopy, were used to study synthetic AB-type carbonate hydroxylapatite (CHAp). 13C{1H} heteronuclear correlation (HetCor) experiments indicate that the two carbonate environments represented by the peaks at δC = 169.8 and 170.8 ppm are associated with three H environments with one environment represented by a peak centered about δH = 0.0 ppm and two additional peaks located at 1.3 and 5.5 ppm. The peaks near δH = 0.0 ppm correspond to hydroxyl environments within the channels of the CHAp, whereas those at 1.3 and 5.5 exhibit spectral characteristics consistent with bicarbonate ions that donate moderate to weak hydrogen bonds. Possible methods by which bicarbonate incorporation can be accommodated by the apatite structure are discussed. The Na/carbonate ratio and 23Na NMR spectroscopy indicate that Na plays an important role in the carbonate incorporation in these materials.