scholarly journals Influence of Selected Saccharides on the Precipitation of Calcium-Vaterite Mixtures by the CO2 Bubbling Method

Crystals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 117 ◽  
Author(s):  
Donata Konopacka-Łyskawa ◽  
Natalia Czaplicka ◽  
Barbara Kościelska ◽  
Marcin Łapiński ◽  
Jacek Gębicki

Calcium carbonate is a compound existing in living organisms and produced for many biomedical applications. In this work, calcium carbonate was synthesized by a CO2 bubbling method using ammonia as a CO2 absorption promotor. Glucose, fructose, sucrose, and trehalose were added into the reaction mixture to modify characteristics of precipitated calcium carbonate particles. To determine the polymorphic form of produced calcium carbonate particles, Fourier transform infrared spectroscopy (FTIR-ATR) and X-ray diffraction (XRD) analysis were performed. Scanning electron microscopy (SEM) was used to estimate the size and shape of produced particles. Mixtures of vaterite and calcite were synthesized in all experiments. The percentage content of the vaterite in the samples depended on used additive. The highest concentration of vaterite (90%) was produced from a solution containing sucrose, while the lowest concentration (2%) was when fructose was added. Saccharides affected the rate of CO2 absorption, which resulted in a change in the precipitation rate and, therefore, the polymorphic composition of calcium carbonate obtained in the presence of saccharides was more varied.

2012 ◽  
Vol 620 ◽  
pp. 12-16 ◽  
Author(s):  
Abdul Rashid Jamaludin ◽  
Shah Rizal Kasim ◽  
Zainal Arifin Ahmad

The effects of calcium carbonate (CaCO3) addition on the physical properties of ZnO-based crystal glaze batches were investigated. Samples were fired at different gloss firing temperatures ranging from 1180-1220°C with 3 hours soaking at 1060°C crystallization temperature. X-ray diffraction (XRD) analysis identifiedthe crystal phase occurred as willemite (Zn2SiO4) and the scanning electron microscope (SEM) analysis indicated that willemite crystals are in the acicular needle like shape that formed spherulite. The intensities of willemite peaks decreased with CaCO3 addition and completely vanished at 5.0 wt% CaCO3. Varied formation of spherulites developed of the surface of crystal glaze as the flows of the glaze stretched further as the amount of CaCO3 increased.


2021 ◽  
Vol 3 (1) ◽  
pp. 8-11
Author(s):  
Yelmida Azis ◽  
Cory Dian Alfarisi ◽  
Komalasari Komalasari ◽  
Khairat Khairat ◽  
Yusnimar Sahan

Hydroxyapatite (HAp, Ca10(PO4)6(OH)2) is the most stable form of calcium phosphate and widely used in various medical applications, mainly in orthopedics and dentistry due to its close similarities with the inorganic mineral component of bone and teeth. This study aims to synthesize hydroxyapatite from duck eggshell using the precipitation method. The duck eggshell was calcined, hydrated (slaking) and underwent carbonation to form Precipitated Calcium Carbonate (PCC).  Afterwards, (NH4)2HPO4 was added to produce HAp by varying the molar ratio of Ca/P by 1.67, 1.77 and 1.87 and stirring speed by 200, 250, 300rpm under basic condition (pH 10 – 11). The best results were obtained at a molar ratio of 1.77 with 200rpm stirring speed. Furthermore, the X-ray Diffraction (XRD) analysis showed that its crystals were hexagonal with sizes of 23.062nm, in the absence of other crystalline phases. Therefore, the hydroxyapatite was obtained in the agglomerates form with a specific surface area of ??55.929m2/g.


Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1129
Author(s):  
Luyara de Almeida Cavalcante ◽  
Laís Sibaldo Ribeiro ◽  
Mitsuo Lopes Takeno ◽  
Pedro Tupa Pandava Aum ◽  
Yanne Katiussy Pereira Gurgel Aum ◽  
...  

The present work demonstrates the production of chlorapatite (ClAp) through thermal decomposition of chemically treated fish scales, originating from an Amazon fish species (Arapaima gigas). The scales were treated with hydrochloric acid (HCl) solution for deproteinization. Afterwards, the solution was neutralized by sodium hydroxide (NaOH) treatment to obtain an apatite-rich slurry. The heat treatment was carried out at different temperatures including 600 °C, 800 °C, and 1000 °C. The powders obtained were characterized through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM). The XRD analysis and FTIR spectra confirmed the incorporation of chlorine into the apatite structure. The FTIR results showed absorption bands relative to the OH–, PO43− functional groups which are a characteristic of chlorapatite. Moreover, the intensity of the OH–Cl elongation could be observed. Chlorapatite Ca5(PO4)3Cl, NaCl, and NaCaPO4 phases were identified, achieving up to 87.4 wt% for ClAp. The SEM observations show that with increasing temperature, the ClAp obtained consists of slightly larger, more crystalline grains. Furthermore, the grains ranged in size, between 1-5 μm and ClAp1000 sample recorded crystallinity of 84.27%. ClAp and NaCaPO4 can be used in electronics as phosphor materials due to their luminescence and biomedical applications.


2015 ◽  
Vol 3 (1) ◽  
pp. 12
Author(s):  
Budi Hermawan ◽  
Syukri Arief ◽  
Novesar Jamarun

 ABSTRACT Precipitated Calcium Carbonate (PCC) is the limestone product resulting from certain process steps. By XRF measurement it has found that the content of CaO (oxide calcium) in limestone Bukit Tui Padang Panjang as follows 54.19%, SiO2 1.03%, Al2O3 0.39%, MgO 0.46% and Fe2O3 0.2%. Rendemen PCC at optimum concentration of 0.75 M HCl is 69.77%. The formation of PCC by using the highest PCC rendemen aquabides is 9.28% at optimum temperature of 50°C. With 0.75 M HCl, the highest rendemen is 79.32% at optimum temperature 70°C. The formation of crystals in the form vaterite, aragonite and calcite were evidenced by X-ray Diffraction (XRD). Treatment with 2.00 M HCl at 30°C showed the formation of vaterite (45.83%), aragonite (35.93%) and calcite (18.24%) with crystals size of 28.43 nm. In the other case, preparation with 0.75 M HCl at 30°C resulting the percentage of vaterite and aragonite which were 73.01% and 26.99% respectively fairished 28.06 nm. Then for the one which were treated with 0.75 M HCl at 70°C indicated the formation of vaterite (75.53%) fairished 33.68 nm and aragonite (24.47%). SEM (Scanning Electron Microscopy) towards the sample prepared from 0.75 M HCl at 30°C have clearly shown that the particle sphere fairished at 3.68 nm where the one treated with 0.75 M HCl at 70°C having particle sphere fairished at 3.3 µm showing needle like estimated of 3.8 µm. Keywords : Precipitated Calcium Carbonate (PCC), caustic soda method 


TAPPI Journal ◽  
2011 ◽  
Vol 10 (1) ◽  
pp. 17-23
Author(s):  
KEVIN TAYLOR ◽  
RICH ADDERLY ◽  
GAVIN BAXTER

Over time, performance of tubular backpulse pressure filters in kraft mills deteriorates, even with regular acid washing. Unscheduled filter replacement due to filter plugging results in significant costs and may result in mill downtime. We identified acid-insoluble filter-plugging materials by scanning electron microscope/energy-dispersion X-ray spectroscopy (SEM/EDS) and X-ray diffraction (XRD) analysis in both polypropylene and Gore-Tex™ membrane filter socks. The major filter-plugging components were calcium sulfate (gypsum), calcium phosphate (hydroxylapatite), aluminosilicate clays, metal sulfides, and carbon. We carried out detailed sample analysis of both the standard acid-washing procedure and a modified procedure. Filter plugging by gypsum and metal sulfides appeared to occur because of the acid-washing procedure. Gypsum formation on the filter resulted from significant hydrolysis of sulfamic acid solution at temperatures greater than 130°F. Modification of the acid-washing procedure greatly reduced the amount of gypsum and addition of a surfactant to the acid reduced wash time and mobilized some of the carbon from the filter. With surfactant, acid washing was 95% complete after 40 min.


Author(s):  
Erdoğan Karip ◽  
Mehtap Muratoğlu

People are exposed to different kinds of diseases or various accidents in life. Hydroxyapatite (HA) has been widely employed for bone treatment applications. In this study, HA was extracted from sheep bones. Bio-composites were doped with 1, 5, and 10 wt.% of expanded perlite and 5 wt.% of ZrO2–MgO-P2O5. The bio-composites were prepared by the cold isostatic pressing method (250 MPa) and sintered at 900°C for 1 h. In order to evaluate the characteristics of the bio-composites, microhardness, density, X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FT-IR), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) analyses were carried out on them. Additionally, the specimens whose characteristics were determined were kept in synthetic body fluid (SBF), and their in vitro behavior was examined. As a result, it was observed that microhardness increased as both the weight and the grain size of the expanded perlite were increased. Calcium silicate, tri-calcium phosphate, and hydroxyapatite were observed in the XRD analysis of all samples, and the formation of apatite structures was increased by addition of ZrO2–MgO–P2O5.


Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1969
Author(s):  
Riccardo Scarfiello ◽  
Elisabetta Mazzotta ◽  
Davide Altamura ◽  
Concetta Nobile ◽  
Rosanna Mastria ◽  
...  

The surface and structural characterization techniques of three atom-thick bi-dimensional 2D-WS2 colloidal nanocrystals cross the limit of bulk investigation, offering the possibility of simultaneous phase identification, structural-to-morphological evaluation, and surface chemical description. In the present study, we report a rational understanding based on X-ray photoelectron spectroscopy (XPS) and structural inspection of two kinds of dimensionally controllable 2D-WS2 colloidal nanoflakes (NFLs) generated with a surfactant assisted non-hydrolytic route. The qualitative and quantitative determination of 1T’ and 2H phases based on W 4f XPS signal components, together with the presence of two kinds of sulfur ions, S22− and S2−, based on S 2p signal and related to the formation of WS2 and WOxSy in a mixed oxygen-sulfur environment, are carefully reported and discussed for both nanocrystals breeds. The XPS results are used as an input for detailed X-ray Diffraction (XRD) analysis allowing for a clear discrimination of NFLs crystal habit, and an estimation of the exact number of atomic monolayers composing the 2D-WS2 nanocrystalline samples.


Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 852
Author(s):  
Asiful H. Seikh ◽  
Hossam Halfa ◽  
Mahmoud S. Soliman

Molybdenum (Mo) is an important alloying element in maraging steels. In this study, we altered the Mo concentration during the production of four cobalt-free maraging steels using an electroslag refining process. The microstructure of the four forged maraging steels was evaluated to examine phase contents by optical microscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) analysis. Additionally, we assessed the corrosion resistance of the newly developed alloys in 3.5% NaCl solution and 1 M H2SO4 solution through potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. Furthermore, we performed SEM and energy-dispersive spectroscopy (EDS) analysis after corrosion to assess changes in microstructure and Raman spectroscopy to identify the presence of phases on the electrode surface. The microstructural analysis shows that the formation of retained austenite increases with increasing Mo concentrations. It is found from corrosion study that increasing Mo concentration up to 4.6% increased the corrosion resistance of the steel. However, further increase in Mo concentration reduces the corrosion resistance.


2020 ◽  
Vol 849 ◽  
pp. 113-118
Author(s):  
Yayat Iman Supriyatna ◽  
Slamet Sumardi ◽  
Widi Astuti ◽  
Athessia N. Nainggolan ◽  
Ajeng W. Ismail ◽  
...  

The purpose of this study is to characterize Lampung iron sand and to conduct preliminary experiments on the TiO2 synthesis which can be used for the manufacturing of functional food packaging. The iron sand from South Lampung Regency, Lampung Province that will be utilized as raw material. The experiment was initiated by sieving the iron sand on 80, 100, 150, 200 and 325 mesh sieves. Analysis using X-Ray Fluorescence (XRF) to determine the element content and X-Ray Diffraction (XRD) to observe the mineralization of the iron sand was conducted. The experiment was carried out through the stages of leaching, precipitation, and calcination. Roasting was applied firstly by putting the iron sand into the muffle furnace for 5 hours at a temperature of 700°C. Followed by leaching using HCl for 48 hours and heated at 105°C with a stirring speed of 300 rpm. The leaching solution was filtered with filtrate and solid residue as products. The solid residue was then leached using 10% H2O2 solution. The leached filtrate was heated at 105°C for 40 minutes resulting TiO2 precipitates (powder). Further, the powder was calcined and characterized. Characterization of raw material using XRF shows the major elements of Fe, Ti, Mg, Si, Al and Ca. The highest Ti content is found in mesh 200 with 9.6%, while iron content is about 80.7%. While from the XRD analysis, it shows five mineral types namely magnetite (Fe3O4), Rhodonite (Mn, Fe, Mg, Ca) SiO3, Quart (SiO2), Ilmenite (FeOTiO2) and Rutile (TiO2). The preliminary experiment showed that the Ti content in the synthesized TiO2 powder is 21.2%. The purity of TiO2 is low due to the presence of Fe metal which is dissolved during leaching, so that prior to precipitation purification is needed to remove impurities such as iron and other metals.


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