Biogenic Nanoparticles of Calcium Carbonate - Preparation and Behaviour

2020 ◽  
Vol 994 ◽  
pp. 197-204
Author(s):  
Dora Kroisová ◽  
Štěpánka Dvořáčková

Calcium carbonate is one of the most widespread natural material. Biogenic calcium carbonate nanoparticles are biocompatible. Currently, they are of great interest for their possible applications, especially in medicine. The aim of this introductory experimental study is to present a simple preparation of biogenic nanoparticles of calcium carbonate from natural resources with a subsequent specific behaviour of nanoparticles in aquatic environment. Different type of shells were used for the preparation of nanoparticles. All structures were burned at 850°C and then grounded to powder. The obtained powders were left in normal laboratory environment for 2 weeks and then placed in beakers with distilled water. Subsequently, two homogenization routes were used - stirring at 1000 rpm for 5 minutes and ultrasonic stirring for 5 minutes. One part of the particles was separated at the bottom of the beaker, but small formations started to create a fractal structure on the surface of water. These formations gradually increased. Crystalline interconnected structures built up with nanoparticles were confirmed by a subsequent analysis by a scanning electron microscope. EDX analysis confirmed the presence of calcium carbonate.

Author(s):  
Toshihiko Takita ◽  
Tomonori Naguro ◽  
Toshio Kameie ◽  
Akihiro Iino ◽  
Kichizo Yamamoto

Recently with the increase in advanced age population, the osteoporosis becomes the object of public attention in the field of orthopedics. The surface topography of the bone by scanning electron microscopy (SEM) is one of the most useful means to study the bone metabolism, that is considered to make clear the mechanism of the osteoporosis. Until today many specimen preparation methods for SEM have been reported. They are roughly classified into two; the anorganic preparation and the simple preparation. The former is suitable for observing mineralization, but has the demerit that the real surface of the bone can not be observed and, moreover, the samples prepared by this method are extremely fragile especially in the case of osteoporosis. On the other hand, the latter has the merit that the real information of the bone surface can be obtained, though it is difficult to recognize the functional situation of the bone.


2019 ◽  
Vol 966 ◽  
pp. 200-203
Author(s):  
Zaenal Arifin ◽  
Triwikantoro ◽  
Bintoro Anang Subagyo ◽  
Mochamad Zainuri ◽  
Darminto

Abstract. In this study, the CaCO3 powder has been successfully synthesized by mixing CaCl2 from natural limestone and Na2CO3 in the same molar ratio. The mixing process of solutions was carried out by employing the molar contents of 0.125, 0.25, 0.375 and 0.5M at varying temperatures of 30, 40, 60 and 80ᴼC. The produced CaCO3 microparticles were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The highest content of aragonite phase with morphology rod-like of the samples is around 29 wt%, resulting from the process using solution of 0.125 M at 80 ᴼC. While at 30 ᴼC and 40 ᴼC produced 100 wt% calcite phase.


2020 ◽  
Vol 984 ◽  
pp. 3-10
Author(s):  
Wei Fang Zhang ◽  
Xing Yu Gao ◽  
Xiao Peng Liu ◽  
Xue Rong Liu

The fatigue life and fatigue stress of 30CrMnSiA material are studied by fracture retro estimation under experimental conditions. With the help of Scanning electron microscopy (SEM), fatigue crack can be observed. By Paris law, the fatigue life and fatigue stress of 30CrMnSiA material can be estimated by fatigue striation under the experimental environment. The method is simple and feasible, and the relative error is lower.


2016 ◽  
Vol 22 (1) ◽  
pp. 22-38 ◽  
Author(s):  
Gilles Luquet ◽  
Yannicke Dauphin ◽  
Aline Percot ◽  
Murielle Salomé ◽  
Andreas Ziegler ◽  
...  

AbstractThe crayfish Cherax quadricarinatus stores calcium ions, easily mobilizable after molting, for calcifying parts of the new exoskeleton. They are chiefly stored as amorphous calcium carbonate (ACC) during each premolt in a pair of gastroliths synthesized in the stomach wall. How calcium carbonate is stabilized in the amorphous state in such a biocomposite remains speculative. The knowledge of the microstructure at the nanometer level obtained by field emission scanning electron microscopy and atomic force microscopy combined with scanning electron microscopy energy-dispersive X-ray spectroscopy, micro-Raman and X-ray absorption near edge structure spectroscopy gave relevant information on the elaboration of such an ACC-stabilized biomineral. We observed nanogranules distributed along chitin-protein fibers and the aggregation of granules in thin layers. AFM confirmed the nanolevel structure, showing granules probably surrounded by an organic layer and also revealing a second level of aggregation as described for other crystalline biominerals. Raman analyses showed the presence of ACC, amorphous calcium phosphate, and calcite. Elemental analyses confirmed the presence of elements like Fe, Na, Mg, P, and S. P and S are heterogeneously distributed. P is present in both the mineral and organic phases of gastroliths. S seems present as sulfate (probably as sulfated sugars), sulfonate, sulfite, and sulfoxide groups and, in a lesser extent, as sulfur-containing amino acids.


2012 ◽  
Vol 727-728 ◽  
pp. 1313-1316 ◽  
Author(s):  
Maria Virginia Gelfuso ◽  
Gabriel Moreira Lima ◽  
Daniel Thomazini

In this work CCTO have been synthesized in two different chemical precursors: calcium hydroxide and copper sulfate were used to compose CCTO-S powder while calcium carbonate and copper nitrate were used to form CCTO-N powder. Calcinations conditions were dramatically different in terms of shelf time and temperature. The CCTO phase was fully obtained for 3 hours of calcination in CCTO-N against the 24 hours to form the same phase in CCTO-S powder. Ceramic bodies densities values for CCTO-S samples were 95% of theoretical density (5.05 g/cm3) and 98% for CCTO-N. The dielectric constant, at room temperature, was obtained for ceramics processed by two routes. Microstructural analysis was conducted by Scanning Electron Microscopy (SEM) and it was performed to explain the dielectric constant differences between CCTO-S and CCTO-N ceramics.


2009 ◽  
Vol 42 (2) ◽  
pp. 225-233 ◽  
Author(s):  
C. C. Tang ◽  
S. P. Thompson ◽  
J. E. Parker ◽  
A. R. Lennie ◽  
F. Azough ◽  
...  

Vaterite is one of three polymorphs of calcium carbonate (CaCO3) found in nature, the others being calcite and aragonite. Here the formation of vaterite from decomposition of ikaite (CaCO3·6H2O) was investigated using synchrotron powder diffraction and scanning electron microscopy. The crystallite sizes of vaterite (∼40 nm) were found to be much smaller than those of the precursor ikaite (∼0.5–1.0 µm) as a result of vaterite nucleating as ikaite dehydrates. The rate of decomposition to vaterite increases with temperature, indicating kinetic control of this transformation. It is postulated that the structural arrangement of the hydration sphere around Ca2+in ikaite determines the orientation of Ca2+and CO32−ions such that vaterite nucleates upon dehydration. This implies that the dehydration of a precursor hydrated phase such as ikaite is required for vaterite nucleation.


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.


2010 ◽  
Vol 108-111 ◽  
pp. 184-189 ◽  
Author(s):  
Qiang Liu ◽  
Bing Jian Zhang

Historic stone materials have to deal with weathering. The desire to preserve cultural heritage created a wide variety of products to reduce the rate of stone decay and to strengthen decayed stone, but it is difficult to evaluate their protective efficiencies. In this paper, a simple preparation method of an imitation of weathering stone is reported. The imitation was prepared with calcium carbonate particles mixed with water. Then, using imitations as the consolidated objects, the consolidation efficiency of a novel biomimetic protectant was investigated. The experimental results indicate that the evaluation method is simple and feasible, and the selected protectant does perform a favorable function of consolidant. The characterization method is helpful in numerically giving some direct indications of the consolidation effectiveness.


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11527
Author(s):  
Pablo Santana ◽  
Dalila Aldana Aranda

The microstructure and nanostructure of nacre in Pteria colymbus were studied with high-resolution field emission scanning electron microscopy (FESEM). The tablets were found to be flat and polyhedral with four to eight sides, and lengths ranging from 0.6 to 3.0 µm. They consisted of nanocrystals 41 nm wide, growing in the same direction. X-ray diffraction showed the crystals to be mineral phase aragonite, which was confirmed by Raman spectroscopy. Fourier transform infrared spectroscopy identified a band at 1,786.95 cm−1 attributed to carboxylate (carbonyl) groups of the proteins present in the organic matrix as well as bands characteristic of calcium carbonate. X-ray fluorescence showed the nacre to contain 98% calcium carbonate, as well as minor elements (Si, Na, S and Sr) and trace elements (Mg, P, Cu, Al, Fe, Cl, K and Zn).


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