Physicochemical characterization of biogenic calcium carbonate

MRS Advances ◽  
2018 ◽  
Vol 3 (61) ◽  
pp. 3569-3574
Author(s):  
Katari P. Rocha ◽  
Santiago Botasini ◽  
Eduardo Méndez

ABSTRACTBiogenic minerals are widely studied materials for their particular properties derived from their hierarchical structure, using building blocks with sizes spanning several orders of magnitude. These special features can be assessed with different analytical tools, and it is important to know their capabilities and limitations. In order to determine the hierarchical structure of the shells, the nacre and prismatic layers of two marine animals were characterized by infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. Based on these assessments, we found that the combination of these three techniques is useful to describe each structure level, and to explain some of the unique properties observed in these natural materials.

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 4200-4211
Author(s):  
Ulises Carranza-Nuñez ◽  
Salomon Ramiro Vasquez-Garcia ◽  
Nelly Flores-Ramirez ◽  
Hamdy Ahmed Abdel-Gawwad ◽  
José Luis Rico ◽  
...  

Characterization of Ceiba aesculifolia (CA) fibers by various techniques is herein reported. The seed pods were collected, and the fibers surrounding the seeds were characterized or treated in an oven at 100 °C prior to characterization by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis coupled with a differential scanning calorimeter (TGA-DSC). The SEM micrographs showed that the natural material is comprised of tubes of external diameter of approximately 27 μm and a mean wall thickness of about 0.62 μm. The results also indicated that the tubes begin to decompose at approximately 220 °C.


2007 ◽  
Vol 1008 ◽  
Author(s):  
Micha Jost ◽  
Peter Gerstel ◽  
Joachim Bill ◽  
Fritz Aldinger

AbstractIn this paper, the suitability of DNA- and RNA-bases, nucleosides and nucleotides, and DNA itself as structure-directing agents for the mineralization of ZnO-based materials is discussed. Those bioorganic molecules are able to trigger the morphology of mineralization products ranging from smooth, homogenous thin films to sponge-like, sheet-like and fibrous products. Besides the investigation of morphological features by scanning electron microscopy, the structural characterization of these materials by X-ray diffraction, vibrational spectroscopy, photoluminescence spectroscopy and photoelectron spectroscopy is discussed.


Author(s):  
R. E. Herfert

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.


2012 ◽  
Vol 620 ◽  
pp. 314-319
Author(s):  
Nur Amira Mamat Razali ◽  
Fauziah Abdul Aziz ◽  
Saadah Abdul Rahman

Hardwood is wood from angiosperm trees. The characteristic of hardwood include flowers, endosperm within seeds and the production of fruits that contain the seeds. This paper aims to discuss the preparation and characterization of cellulose obtained from hardwood. The hardwood Merbau (Intsia bijuga) was chosen as raw material in this study. Alkaline treatment and delignification methods were used for the preparation of cellulose. Acid hydrolysis was employed to produce cellulose nanocrystal (CNC). The treated and untreated samples were characterized using x-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The final product, from both trated and untreated samples were then compared.


2012 ◽  
Vol 174-177 ◽  
pp. 508-511
Author(s):  
Lin Lin Yang ◽  
Yong Gang Wang ◽  
Yu Jiang Wang ◽  
Xiao Feng Wang

BiFeO3 polyhedrons had been successfully synthesized via a hydrothermal method. The as-prepared products were characterized by power X-ray diffraction (XRD) pattern, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The possible mechanisms for the formation of BiFeO3 polyhedrons were discussed. Though comparison experiments, it was found that the kind of precursor played a key role on the morphology control of BiFeO3 crystals.


1989 ◽  
Vol 4 (6) ◽  
pp. 1320-1325 ◽  
Author(s):  
Q. X. Jia ◽  
W. A. Anderson

Effects of hydrofluoric acid (HF) treatment on the properties of Y–Ba–Cu–O oxides were investigated. No obvious etching of bulk Y–Ba–Cu–O and no degradation of zero resistance temperature were observed even though the oxides were placed into 49% HF solution for up to 20 h. Surface passivation of Y–Ba–Cu–O due to HF immersion was verified by subsequent immersion of Y–Ba–Cu–O in water. A thin layer of amorphous fluoride formed on the surface of the Y–Ba–Cu–O during HF treatment, which limited further reaction between Y–Ba–Cu–O and HF, and later reaction with water. Thin film Y–Ba–Cu–O was passivated by HF vapors and showed no degradation in Tc-zero after 30 min immersion in water. The properties of the surface layer of Y–Ba–Cu–O oxide after HF treatment are reported from Auger electron spectroscopy, x-ray diffraction, and scanning electron microscopy studies.


2021 ◽  
pp. 004051752110154
Author(s):  
Zhihui Qin ◽  
Shuyuan Zhao ◽  
Liu Liu ◽  
Zhaohe Shi ◽  
Longdi Cheng ◽  
...  

Degumming is the dominant method for insolating lignocellulosic fibers in textile applications. Traditional alkaline degumming (TAL), as a common method, requires a high-concentration alkali and has been a severe challenge to the environment. In the research reported here, the possibility of innovative jute degumming by organic solvents 1-2 propylene glycol and a combination of additive green oxygen (GO-OS) was studied. The results revealed that fibers could be extracted by this system (under condition of 0.9% GO-OS, 180°C, 120 min), and obtained fibers with higher breaking tenacity (7.1 cN/dtex), yield (65.7%), breaking elongation (2.87%) and residual gum (11.7%), which all meet the requirement of the relevant Chinese Textile National Standards. Notably, the required reaction time (120 min) of the GO-OS system was 180 min shorter than that of the TAL method. Furthermore, the modifications introduced by the degumming effect on physicochemical aspects were characterized and confirmed by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction. This study provides a promising degumming method for separating jute lignocellulose without acid and alkali consumption.


2022 ◽  
Vol 321 ◽  
pp. 126326
Author(s):  
Gladis Aparecida Galindo Reisemberger de Souza ◽  
Ramón Sigifredo Cortés Paredes ◽  
Frieda Saicla Barros ◽  
Gustavo Bavaresco Sucharski ◽  
Sebastião Ribeiro Junior ◽  
...  

2016 ◽  
Vol 34 (2) ◽  
pp. 412-417
Author(s):  
Esra Öztürk

AbstractIn this work, aluminate type phosphorescence materials were synthesized via the solid state reaction method and the photoluminescence (PL) properties, including excitation and emission bands, were investigated considering the effect of trace amounts of activator (Eu3+) and co-activator (Dy3+). The estimated thermal behavior of the samples at certain temperatures (> 1000 °C) during heat treatment was characterized by differential thermal analysis (DTA) and thermogravimetry (TG). The possible phase formation was characterized by X-ray diffraction (XRD). The morphological characterization of the samples was performed by scanning electron microscopy (SEM). The PL analysis of three samples showed maximum emission bands at around 610 nm, and additionally near 589 nm, 648 nm and 695 nm. The bands were attributed to typical transitions of the Eu3+ ions.


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