scholarly journals Scale precipitation on HDPE pipe by degassing of CO2 dissolved in water

2021 ◽  
Author(s):  
Rachid Ketrane ◽  
Celia Yahiaoui
Keyword(s):  
Calcium Carbonate ◽  
Process Efficiency ◽  
Major Constituent ◽  
X Ray Diffraction ◽  
Hdpe Pipe ◽  
Scaling Process ◽  
Weighing Method ◽  
Ph Decrease ◽  
Critical Ph

Abstract In Algeria, high-density polyethylene (HDPE) is widely used in drinking water pipes. This study is focused on the precipitation of calcium carbonate, a major constituent of scale, from calcocarbonically pure (CCP) water in HDPE pipe. Studying scaling in natural conditions is very difficult because it occurs over many years. For this, accelerated scaling is caused by the degassing CO2 dissolved in water. The kinetic study has shown that the germination time and the critical pH decrease with the hardness (30, 40 and 50 °f) and temperature (30, 40 and 50 °C) of water. On the other hand, scaling process efficiency (η) and the supersaturation coefficient (Ωcal) of CaCO3 increase with these parameters. The CaCO3 precipitation occurs both in solution and on walls of HDPE. By the weighing method, it is shown that the deposit mass increases with hardness and temperature. Calcium carbonate precipitates much more in homogeneous phase than in heterogeneous one. The study also showed that heterogeneous nucleation on HDPE is much less important than on PA, PVC, chrome and Inox. These measurements are supported by the characterization of X-ray diffraction deposits and by scanning electron microscopy, which recognizes that the precipitate obtained consists mainly of calcite.

scholarly journals Luminescence reveals variations in local structural order of calcium carbonate polymorphs formed by different mechanisms

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Michael B. Toffolo ◽  
Giulia Ricci ◽  
Luisa Caneve ◽  
Ifat Kaplan-Ashiri
Keyword(s):  
Infrared Spectroscopy ◽  
Calcium Carbonate ◽  
Construction Materials ◽  
Reference Database ◽  
Formation Processes ◽  
X Ray Diffraction ◽  
Structural Order ◽  
Lime Plaster ◽  
Calcium Carbonate Polymorphs

Abstract In nature, calcium carbonate (CaCO3) in the form of calcite and aragonite nucleates through different pathways including geogenic and biogenic processes. It may also occur as pyrogenic lime plaster and laboratory-precipitated crystals. All of these formation processes are conducive to different degrees of local structural order in CaCO3 crystals, with the pyrogenic and precipitated forms being the least ordered. These variations affect the manner in which crystals interact with electromagnetic radiation, and thus formation processes may be tracked using methods such as X-ray diffraction and infrared spectroscopy. Here we show that defects in the crystal structure of CaCO3 may be detected by looking at the luminescence of crystals. Using cathodoluminescence by scanning electron microscopy (SEM-CL) and laser-induced fluorescence (LIF), it is possible to discern different polymorphs and their mechanism of formation. We were thus able to determine that pyrogenic calcite and aragonite exhibit blue luminescence due to the incorporation of distortions in the crystal lattice caused by heat and rapid precipitation, in agreement with infrared spectroscopy assessments of local structural order. These results provide the first detailed reference database of SEM-CL and LIF spectra of CaCO3 standards, and find application in the characterization of optical, archaeological and construction materials.

Characterization of Cellulose/Calcium Carbonate Biocomposite Film

2016 ◽  
Vol 675-676 ◽  
pp. 209-212 ◽  
Author(s):  
Wichian Siriprom ◽  
Nirun Witit-Anun ◽  
Auttapol Choeysuppaket ◽  
T. Ratana
Keyword(s):  
Calcium Carbonate ◽  
Composite Film ◽  
X Ray Diffraction ◽  
X Ray ◽  
Film Forming ◽  
Ft Ir ◽  
Good Biocompatibility ◽  
Biocomposite Film ◽  
Calcium Carbonate Particle

In this study were to explore the properties of interaction between cellulose and calcium carbonate particle (CaCO3) which derive from Papia Undulates Shell in procedure of biocomposite synthesis. The structural properties of cellulose powder Papia Undulates Shell and cellulose-calcium carbonate composite film were investigated by using X-ray Diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) and the compositions of cellulose/CaCO3 biocomposite film were studied by Energy Dispersive X-ray Fluorescence (EDXRF). The experimental results demonstrated the morphology of Papia Undulates Shell were crystalline aragonite phase and the cellulose have structural as amorphous-crystalline but after film forming the composite film between cellulose and Papia Undulates Shell also have amorphous structural. The result of FTIR used to confirmed the formation of bonding between molecular, it indicated that the cellulose/CacO3 biocomposite film had good biocompatibility due to the biocomposite film have both characteristic feature of CO3-2 group (~874 cm-1 and ~713 cm-1) and the glucose of cellulose at ~1635, ~1064 and ~946 cm-1. Another that, the result from EDXRF shown the chemical composition of organic compound of cellulose/CaCO3 biocomposite film was highest with 99.437 while the Papia Undulates Shell have 0.341 Wt% with corresponding with the ratio of filler material which mixture as 1%. So that, the cellulose/calcium carbonate bicomposite film could be candidate for biocomposite film application.

scholarly journals CALCIUM OXIDE CHARACTERISTICS PREPARED FROM AMBUNTEN’S CALCINED LIMESTONE

2018 ◽  
Vol 5 (1) ◽  
pp. 65 ◽  
Author(s):  
Fatimatul Munawaroh ◽  
Laila Khamsatul Muharrami ◽  
Triwikantoro Triwikantoro ◽  
Zaenal Arifin
Keyword(s):  
Calcium Carbonate ◽  
Chemical Composition ◽  
Calcium Oxide ◽  
Crystalline Phase ◽  
Wave Number ◽  
Test Results ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxide Characteristics

<pre>Calcium oxide (CaO) and calcium carbonate (CaCO3) are widely used in industry. CaO and CaCO3 can be synthesized or derived from limestone. The purpose of this study to determine the characteristics of CaO calcined limestone from Ambunten Sumenep. Lime in calcined at 850 ° C for 6 hours. Characterization of X-ray fluorescence (XRF) was conducted to determine the chemical composition of limestone, X-ray diffraction test (XRD) to find the lime crystalline phase and FTIR test to determine the absorption of wave number. XRF test results showed that the limestone chemical composition consisted of Ca of 95.37% as the dominant element, Mg of 4.1%, Fe 0.17% and Y by 0.39%. The XRD test results showed that the limestone crystal phase is ankerite (Ca [Fe, Mg] [CO3] 2) and after the calcined phase calcination is vaterite (Ca [OH] 2), calcite (CaO) and calcite (CaCO3). While the FTIR test results show that the CaO spectra are seen at 3741.24, 1417.12 and 874.14 cm</pre><sup>-1</sup><pre>.</pre>

Synthesis and Characterization of Dumbbell Shaped Calcium Carbonate Induced by Lignin

2010 ◽  
Vol 658 ◽  
pp. 49-52 ◽  
Author(s):  
Wen Kun Zhu ◽  
Xue Gang Luo ◽  
An Kai Luo ◽  
Xuan Liang
Keyword(s):  
Infrared Spectroscopy ◽  
Calcium Carbonate ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Synthesis Mechanism ◽  
Ft Ir ◽  
Ir Analysis ◽  
Decomposition Behavior ◽  
Normal Calcium

Calcium carbonate with various structures and morphologies were prepared under double injection of the CaCl2 and Na2CO3 solutions with molar ratio of 1:1 at 30 °C, taking lignin as the induction agents. They were characterized by scanning electron microscopy, infrared spectroscopy thermal analysis and X-ray diffraction. The synthesis mechanism was also discussed. The results showed that calcium carbonate of different shape were obtained with the concentration of lignin at 10g/L, 20g/L and 30g/L, respectively, under 30°C while CaCl2 and Na2CO3 were kept at the same concentration of 0.5mol/L. The size of the particles was in a range between 3 and 5μm and the particles were calcites. Compared with the normal calcium carbonate, the compound has advanced thermal decomposition behavior. Fourier transform infrared spectroscopy (FT-IR) analysis revealed the presence of lignin and calcite. The electrostatic interaction of Ca2+ with lignin and the complementary of stereo-structure play important roles in the formation of Dumbbell Shaped Calcium Carbonate.

scholarly journals Preparation and characterization of regenerated cellulose biocomposite film filled with calcium carbonate by in situ precipitation

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 7893-7905
Author(s):  
Qianqian Zhu ◽  
Jingjing Wang ◽  
Jianzhong Sun ◽  
Qianqian Wang
Keyword(s):  
Calcium Carbonate ◽  
Chemical Properties ◽  
Regenerated Cellulose ◽  
X Ray Diffraction ◽  
Uv Visible ◽  
Biocomposite Film ◽  
Physical And Chemical ◽  
And Chemical Properties

The application of cellulose hybrid biocomposites filled with calcium carbonate has attracted wide attention in packaging and other fields in recent years. In this study, regenerated cellulose (RC) films filled with calcium carbonate were successfully prepared by dissolution, regeneration, and in situ precipitation of CaCO3. The optical, mechanical, physical, and chemical properties of biocomposites were examined by UV-visible spectroscopy, tensile testing, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analyses (TGA). The results showed that RC films with different CaCO3 contents exhibited good flexibility, optical properties, mechanical strength, and thermal stability. The RC biocomposite filled with calcium carbonate showed a tensile strength of 84.7 ± 1.5 MPa at optimum conditions. These RC biocomposites filled with CaCO3 may find application in packaging.

Mimicking the Formation of Biomineral Composites through Deposition of Calcium Carbonate Thin-Films on Modified Fiber Net Templates

2003 ◽  
Vol 774 ◽  
Author(s):  
Parayil Kumaran Ajikumar ◽  
Rajamani Lakshminarayanan ◽  
Valiyaveettil Suresh
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electron Microscope ◽  
Calcium Carbonate ◽  
Scanning Electron Microscope ◽  
X Ray Diffraction ◽  
X Ray ◽  
Controlled Deposition ◽  
Scanning Electron

AbstractThin films of calcium carbonate were deposited on the surfaces of synthetic substrates using a simple biomimetic pathway. The Nylon 66 fiber knit pre-adsorbed with acidic polymers was used as a template for the controlled deposition of CaCO3 thin film. The presence of the soluble macromolecules on the fiber knit surface was characterized using ATR-FTIR spectroscopy. The characterization of the mineral films was carried out using scanning electron microscope (SEM), X-ray diffraction (XRD) and energy dispersive Xray scattering (EDX) studies.

XRD, SEM/EDX and FTIR Characterization of Brazilian Natural Coral

2005 ◽  
Vol 284-286 ◽  
pp. 43-46 ◽  
Author(s):  
Herman S. Mansur ◽  
Alexandra A.P. Mansur ◽  
Marivalda Pereira
Keyword(s):  
Calcium Carbonate ◽  
Ftir Spectroscopy ◽  
Biomedical Application ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Ftir Characterization ◽  
Biomimetic Coating ◽  
Natural Coral ◽  
Sem Morphology

In the present work, natural coral from Brazilian reefs were studied according to their crystallography by X-ray diffraction and microstructure by Scanning Electron Microscopy (SEM/EDX). FTIR spectroscopy was also used to evaluate the chemical functionalities and major components present in the material. The SEM morphology results have shown a tri-dimensional coral structure with porous ranging from 50 to 200 µm. Aragonite was identified as the major crystalline phase through XRD analysis and FTIR spectroscopy. Strontium calcium carbonate, (Sr,Ca)CO3, was also identified by XRD analysis. After sintering at 900º/1h, the conversion from aragonite to CaO and calcite was observed. These results have endorsed the high potential application of natural coral materials as 3D scaffolds for biomedical application, because of calcium carbonate compounds can be converted to HA by hydrothermal and biomimetic coating processes.

Structural and mechanical characterization of polyurethane-CaCO3 composites synthesized at high calcium carbonate loading: An experimental and theoretical study

2021 ◽  
pp. 002199832199641
Author(s):  
Ana P de Moura ◽  
Enio HP da Silva ◽  
Vanessa S dos Santos ◽  
Miguel F Galera ◽  
Flaminio CP Sales ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Theoretical Calculations ◽  
Plastic Region ◽  
Mechanical Tests ◽  
Chemical Information ◽  
X Ray Diffraction ◽  
High Calcium ◽  
Ft Ir ◽  
Polymer Interaction

Due to its exceptional biocompatibility, Polyurethane (PU) reinforced with calcium carbonate (CaCO3) is a composite material with significant biomedical applications. However, much of the currently known mechanical and chemical information regarding composites has been obtained at low and moderate CaCO3 content levels. This study employs experimental and theoretical tools to evaluate the structural, morphological, and mechanical properties of pristine polyurethane, and when doped with CaCO3 at 25 and 50 wt.%. In the experiments the samples are characterized using X-ray diffraction (XRD), infrared spectrophotometry (FT-IR), scanning electron microscopy (SEM), and tensile and flexural mechanical tests, while theoretical calculations are performed to evaluate the carbonate-polymer interaction. The XRD and FT-IR results indicate that CaCO3 is at the calcite phase and that PU-CaCO3 materials exhibit a broadening of bands related to the NH2 group. This result is explained using theoretical calculations that demonstrate a weak interaction between those molecules with the CaCO3 surface, where the molecule-calcite interaction occurs primarily through the NH2 molecular link. With respect to mechanical behaviour, the results show less fracture resistance and greater stiffness for the materials containing CaCO3, compared to those containing only PU. These results are explained in terms of the stress concentration due to CaCO3 within the polymer. Finally, the results detailed in this paper show that a high calcium carbonate loading is suitable for increasing the rigidity and decreasing the fracture toughness of the biomaterial, in association with a reduction of the plastic region.

Solvothermal Synthesis and Characterization of Hierarchical Calcium Carbonate Spheres

2014 ◽  
Vol 912-914 ◽  
pp. 318-320 ◽  
Author(s):  
Yin Xia Chen ◽  
Xian Bing Ji ◽  
Yu Lian Quan
Keyword(s):  
Calcium Carbonate ◽  
Solvothermal Synthesis ◽  
Mixed Solvents ◽  
Average Diameter ◽  
Synthesis And Characterization ◽  
Solvothermal Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Experimental Parameters

Hierarchical calcium carbonate spheres composed of nanoparticles has been successfully synthesized via a solvothermal process. The structures are fabricated by the reaction of Ca (CH3COO)2with (CO(NH2)2) at 110 °C in diethylene glycolwater mixed solvents in the presence of polyvinylpyrrolidone. The as-prepared products were characterized by field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). The characterization results revealed that the average diameter of the hierarchical calcium carbonate spheres is about 5 μm, and the size of the nanoparticals range from 50 to 100 nm. In addition, a small amount of bundle-like aragonite calcium carbonate is also obtained in the experimental parameters.

Synthesis of ZnO by Mechanical Activation and Make the Varistor

2011 ◽  
Vol 110-116 ◽  
pp. 1599-1605
Author(s):  
Mahmood Reza Mehran
Keyword(s):  
Raw Materials ◽  
Sol Gel ◽  
Planetary Mill ◽  
Raw Material ◽  
Process Efficiency ◽  
X Ray Diffraction ◽  
Zno Nanopowder ◽  
Direct Band ◽  
Hydrothermal Methods

ZnO is a semiconductor with direct band gap that because of its optical and electronically properties has very interesting for researchers. Wide application of this compound in electronic and optic like piezoelectric transducer, gas sensor, optical waveguide, thin conductor layer and transparent, varistors, photocells, optical U.V. equipments and also variety medical applications with concerning its nature friendly cause that to find the economical method for mass production be concerned. During recent decay, many methods such as sol-gel, wet chemistry, CVD & MOCVD, hydrothermal methods and development process have been invented for ZnO production. The most common problems of these methods are complexity of production process, need to expensive equipments, need to expensive raw materials, need to exceedingly pressure and temperature etc. In this research with activation of Zn as the raw material, nanoparticles of ZnO has been product by a planetary mill and hydride action that this method has ability to extensile in industrial range.SEM investigations approve the nanosize of produced particles. Morphology of particles is more similar to hexagonal crystal structure. Process efficiency is 100 percent and x-ray diffraction (XRD) of resultant powder verifies this. After synthesis and characterization of ZnO nanopowder as one of its application, varistor was made and then electrical property of this part was evaluated.

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