scholarly journals Chemical conversion of a solid body of the composite gypsum/polyhydroxybutyrate in hydroxyapatite/polyhydroxybutyrate

Cerâmica ◽  
2019 ◽  
Vol 65 (375) ◽  
pp. 335-339
Author(s):  
A. A. Barbosa ◽  
S. A. Júnior ◽  
A. C. S. Dantas ◽  
A. V. Ferraz
Keyword(s):  
Ammonium Hydroxide ◽  
Chemical Conversion ◽  
Ph Control ◽  
Raw Material ◽  
Added Value ◽  
X Ray Diffraction ◽  
Before And After ◽  
Ammonium Hydrogen ◽  
Diffraction Patterns ◽  
Clear Change

Abstract The transformation of the gypsum into hydroxyapatite allows added value to this raw material, because the ceramic obtained has a high commercial value in relation to gypsum, while the polymer adds biocompatibility and bioactivity properties to the biocomposite. Thus, hydroxyapatite/polyhydroxybutyrate composites were prepared from the gypsum/polyhydroxybutyrate, using a 10% mass ratio of the polymer. The material was obtained by means of a chemical conversion carried out in a solution of ammonium hydrogen phosphate (0.5 mol.L-1) and alkaline medium (ammonium hydroxide 6.0 mol.L-1) for pH control. The reaction occurred at 100 °C at different test times. Analyzes of infrared spectroscopy showed functional groups characteristic of hydroxyapatite after 36 h of reaction; in addition, the biomaterial was identified as the major phase in X-ray diffraction patterns. Scanning electron microscopy of the materials before and after conversion showed a clear change in their morphologies, indicating the success of the synthesis.

Influence of Synthesis Route on Phase Formation and Sinterability of Hydroxyapatite-Zirconia Composites

2008 ◽  
Vol 591-593 ◽  
pp. 722-727
Author(s):  
Dolores Ribeiro Ricci Lazar ◽  
Sandra Maria Cunha ◽  
Valter Ussui ◽  
E. Fancio ◽  
Nelson Batista de Lima ◽  
...  
Keyword(s):  
Chemical Reactivity ◽  
Ammonium Hydroxide ◽  
Rietveld Analysis ◽  
Yttria Stabilized Zirconia ◽  
Synthesis Process ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Ammonium Hydrogen ◽  
Ammonium Hydrogen Phosphate ◽  
Diffraction Patterns

Reinforcement with yttria stabilized zirconia (YSZ) is an alternative to improve mechanical strength of hydroxyapatite (HAp) ceramic. However, calcium may react with zirconium to form calcium zirconate. In addition, decomposition of HAp to tricalcium phosphate (TCP) occurs with water loss inhibiting ceramic densification. In order to minimize the formation of these compounds, two synthesis routes were compared in this work: coprecipitation of hydrous yttria stabilized zirconia in a calcium phosphate gel medium and powder mixture of individual calcined powders. Composite nominal compositions were fixed at 90 and 95 HAp wt%. Calcium, zirconium and yttrium chlorides and ammonium hydrogen phosphate were the employed precursors. Ammonium hydroxide was the selected precipitation agent. Calcination was performed at 800oC for 1 hour and pellets were sintered in the range of 1150 and 1350oC for 1, 3 and 5 hours. Ceramic samples were characterized by scanning electron microscopy and apparent density measurements. Crystalline phases were quantified by Rietveld analysis of X-ray diffraction patterns. Results indicate that powders prepared by coprecipitation can cause porosity formation due to the higher chemical reactivity during synthesis process.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

Sedimentary Clays as Geopolymer Precursor

2018 ◽  
Vol 39 ◽  
pp. 97-111
Author(s):  
F. Mostefa ◽  
Nasr Eddine Bouhamou ◽  
H.A. Mesbah ◽  
Salima Aggoun ◽  
D. Mekhatria
Keyword(s):  
Sodium Hydroxide ◽  
Mineralogical Composition ◽  
Cementitious Materials ◽  
Raw Material ◽  
X Ray Diffraction ◽  
Calcination Time ◽  
Calorimetric Analysis ◽  
X Ray ◽  
Before And After ◽  
Mechanical Performances

This work aims to study the feasibility of making a geopolymer cement based on dredged sediments, from the Fergoug dam (Algeria) and to evaluate their construction potential particularly interesting in the field of special cementitious materials. These sediments due to their mineralogical composition as aluminosilicates; are materials that can be used after heat treatment. Sedimentary clays were characterized before and after calcination by X-ray diffraction, ATG / ATD, spectroscopy (FTIR) and XRF analysis. The calcination was carried out on the raw material sieved at 80 μm for a temperature of 750 ° C, for 3.4 and 5 hours. The reactivity of the calcined products was measured using isothermal calorimetric analysis (DSC) on pastes prepared by mixing an alkaline solution of sodium hydroxide (NaOH) 8 M in an amount allowing to have a Na / Al ratio close to 1 (1: 1). Also, cubic mortar samples were prepared with a ratio L / S: 0.8, sealed and cured for 24 hours at 60 ° C and then at room temperature until the day they were submited to mechanical testing. to check the extent of geopolymerization. The results obtained allowed to optimize the calcination time of 5 hours for a better reactivity of these sediments, and a concentration of 8M of sodium hydroxide and more suitable to have the best mechanical performances.

scholarly journals Understanding the Performance of a Novel Direct Compression Excipient Comprising Roller Compacted Chitin

Marine Drugs ◽  
2020 ◽  
Vol 18 (2) ◽  
pp. 115 ◽  
Author(s):  
Deeb Abu Fara ◽  
Linda Al-Hmoud ◽  
Iyad Rashid ◽  
Babur Z. Chowdhry ◽  
Adnan Badwan
Keyword(s):  
Ball Milling ◽  
Added Value ◽  
Roller Compaction ◽  
Direct Compression ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ft Ir ◽  
Diffraction Patterns ◽  
Hand Drying ◽  
Slight Deformation

Chitin has been investigated in the context of finding new excipients suitable for direct compression, when subjected to roller compaction. Ball milling was concurrently carried out to compare effects from different energy or stress-inducing techniques. Samples of chitin powders (raw, processed, dried and humidified) were compared for variations in morphology, X-ray diffraction patterns, densities, FT-IR, flowability, compressibility and compactibility. Results confirmed the suitability of roller compaction to convert the fluffy powder of raw chitin to a bulky material with improved flow. X-ray powder diffraction studies showed that, in contrast to the high decrease in crystallinity upon ball milling, roller compaction manifested a slight deformation in the crystal lattice. Moreover, the new excipient showed high resistance to compression, due to the high compactibility of the granules formed. This was correlated to the significant extent of plastic deformation compared to the raw and ball milled forms of chitin. On the other hand, drying and humidification of raw and processed materials presented no added value to the compressibility and compactibility of the directly compressed excipient. Finally, compacted chitin showed direct compression similarity with microcrystalline cellulose when formulated with metronidazole (200 mg) without affecting the immediate drug release action of the drug.

Synthesis and Characterization of Nanopraticle Hematite (α-Fe2O3) Minerals from Natural Iron Sand Using Co-Precipitation Method and its Potential Applications as Extrinsic Semiconductor Materials Type-N

2019 ◽  
Vol 967 ◽  
pp. 259-266 ◽  
Author(s):  
Muhammad Rizal Fahlepy ◽  
Yuyu Wahyuni ◽  
Muhamma Andhika ◽  
Arini Tiwow Vistarani ◽  
Subaer
Keyword(s):  
Ammonium Hydroxide ◽  
Raw Material ◽  
Semiconductor Materials ◽  
Precipitation Method ◽  
Precipitation Process ◽  
Sem Image ◽  
Natural Iron ◽  
Before And After ◽  
Potential Applications ◽  
Co Precipitation

This research is about nanoparticles hematite (NPH) synthesized and characterized from natural iron sands using co-precipitation method and its potential applications as extrinsic semiconductor materials type-N. The aims of this study is to determine the process parameters to obtain hematite of high purity degree and to observe its physical characteristics as an extrinsic semiconductor materials type-N. The iron sand was first separated by magnetic technique and then dissolved into HCl solution before conducting the precipitation process. Precipitation was done by dripping ammonium hydroxide (NH4OH). Precipitated powder was dried at 80°C for 2 hours, and then calcined at 500°C, 600°C 700°C for 2 hours respectively. The composition of iron sands, purity degree, hematite mineral grain size, and space group were analyzed by XRF, XRD, FTIR and SEM. The XRF analysis result of raw material, showed that dominant element and composition in the sample is Fe with purity degree is 90.51%. The XRD result before and after precipitation showed Fe3O4 and α-Fe2O3. Fe3O4 purity degree was obtained 85%, and α-Fe2O3 in NPH500, NPH600, NPH700 were 63%, 83%, and 76%, respectively. FTIR spectral showed crystalline hematite characteristics stong band of 472.07 to 559.62 cm-1. SEM image showed the morphology of agglomeration particulates, when the calcinaton temperature increases, the agglomeration will be seperated due to thermal energy. Based on the charaterization results it was found that the natural iron sand synthesized has the potential to be applied as an N-type extrinsic semiconductor material.

scholarly journals Use of Steel Industry Wastes for the Preparation of Self-Cleaning Mortars

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 621 ◽  
Author(s):  
José Balbuena ◽  
Luis Sánchez ◽  
Manuel Cruz-Yusta
Keyword(s):  
Steel Industry ◽  
Diffuse Reflectance ◽  
Construction Material ◽  
Added Value ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
New Material ◽  
Lamination Process ◽  
Self Cleaning

An important problem, which must be solved, is the accumulation of industrial waste in landfills. Science has an obligation to transform this waste into new products and, if possible, with high added value. In this sense, we propose the valorization of the waste which is generated in the steel lamination process (HSL) through its conversion into a new material with photocatalytic activity which is suitable for use as an additive to obtain a self-cleaning construction material. The valorization of steel husk lamination waste is achieved through a grinding process, which allows the sample to be homogenized, in size, without altering its phase composition, and a thermal treatment that turns it into iron oxide, which acts as a photocatalyst. These residues, before and after treatment, were characterized by different techniques such as PXRD (Powder X-Ray Diffraction), TGA (Thermogravimetric Analysis), SBET (Specific surface area, Brunauer-Emmett-Teller), SEM (Scanning Electron Microscopy) and Diffuse reflectance (DR). MB and RhB tests show that this material is capable of self-cleaning, both of the material itself and when it is incorporated into a construction material (mortar). In addition, the NOx gas elimination test shows that it is also capable of acting on greenhouse gases such as NOx.

scholarly journals Production of Acetyl Cellulose from Agricultural Waste of Oil Palm Empty Fruit Bunches

2019 ◽  
Vol 31 (12) ◽  
pp. 2725-2728
Author(s):  
S.D. Yuwono ◽  
D.A. Iryani ◽  
C. Gusti ◽  
Suharto ◽  
Buhani ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Oil Palm ◽  
Agricultural Waste ◽  
Raw Material ◽  
Added Value ◽  
X Ray Diffraction ◽  
Renewable Materials ◽  
X Ray ◽  
Empty Fruit Bunches

In Indonesia especially in Lampung Province, there are a lot of oil palm empty fruit bunches (OPEFB) as an organic material waste. OPEFB is relatively inexpensive lignocellulose material as raw material of cellulose acetate or acetyl cellulose. In a business to bigger added value out of these natural renewable materials, the production of the acetyl cellulose was performed well by the acetylation of cellulose from OPEFB using different methods. These were extensively characterized using thermogravimetric analysis, Fourier transform infrared spectroscopy and X-ray diffraction. The results indicated that the acetyl cellulose resulted showed similar properties to cotton acetyl cellulose. Degree of substitution of the resultant acetyl cellulose from different methods was improved from 1.86 to 2.60.

Synthesis of (Y,Gd)2O3:Eu nanopowder by a novel co-precipitation processing

2004 ◽  
Vol 19 (12) ◽  
pp. 3586-3591 ◽  
Author(s):  
Jiyang Chen ◽  
Ying Shi ◽  
Jianlin Shi
Keyword(s):  
Electron Microscopy ◽  
Ammonium Hydroxide ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
Hydrogen Carbonate ◽  
Ammonium Hydrogen ◽  
Intense Luminescence ◽  
Co Precipitation

Nano-sized (Y,Gd)2O3:Eu powders were synthesized by a novel co-precipitation processing in which a mixture of ammonium hydroxide and ammonium hydrogen carbonate was adopted as a complex precipitant. Evolution behaviors of precursors during calcinations were studied by means of thermogravimetry-differential scanning calorimetry-mass spectrum, Fourier transform infrared, x-ray diffraction, scanning electron microscopy, and transmission electron microscopy in detail. Nano-sized (Y,Gd)2O3:Eu powder as prepared possessed a primary grain size of about 30 nm and specific surface area of 38 m2/g after being calcined at 850 °C for 2 h, showing much finer grains and less agglomeration. The as prepared nanopowder shows intense luminescence at 611nm under x-ray or ultraviolet excitation. Transparent (Y,Gd)2O3:Eu ceramics can also be fabricated using this high sinterable nanopowder.

scholarly journals Liquid-Phase Catalytic Oxidation of Limonene to Carvone over ZIF-67(Co)

Catalysts ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 374 ◽  
Author(s):  
Yizhou Li ◽  
Yepeng Yang ◽  
Daomei Chen ◽  
Zhifang Luo ◽  
Wei Wang ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Catalytic Oxidation ◽  
Heterogeneous Catalyst ◽  
Product Selectivity ◽  
X Ray Diffraction ◽  
Zeolitic Imidazolate Framework ◽  
X Ray ◽  
Mild Conditions ◽  
Before And After ◽  
Diffraction Patterns

Liquid-phase catalytic oxidation of limonene was carried out under mild conditions, and carvone was produced in the presence of ZIF-67(Co), cobalt based zeolitic imidazolate framework, as catalyst, using t-butyl hydroperoxide (t-BHP) as oxidant and benzene as solvent. As a heterogeneous catalyst, the zeolitic imidazolate framework ZIF-67(Co) exhibited reasonable substrate–product selectivity (55.4%) and conversion (29.8%). Finally, the X-ray diffraction patterns of the catalyst before and after proved that ZIF-67(Co) acted as a heterogeneous catalyst, and can be reused without losing its activity to a great extent.

Second-Generation Aluminium Extraction Residue Used as Devitrification Aid for Glass-Ceramics

2008 ◽  
Vol 587-588 ◽  
pp. 773-777
Author(s):  
M.C. Ferreira ◽  
Wilson Acchar ◽  
Ana M. Segadães ◽  
Sonia Regina Homem de Mello-Castanho
Keyword(s):  
Second Generation ◽  
Glass Ceramics ◽  
Glass Frit ◽  
Raw Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Before And After ◽  
Devitrification Process ◽  
Extraction Metallurgy

Brazil has one of the world’s most important Bauxite deposits, the raw material for the aluminium extraction metallurgy. This work is focused on finding a suitable application for the white dross residue (WDR), a second-generation waste material produced during the metal recovery from the slag left after the primary extraction of aluminium from the ore. A commercial lime-silica based glass frit was used, to which WDR additions were made (up to 30 wt.%), aimed at studying the devitrification process of the glasses produced. Such mixtures were melted at temperatures varying from 1100 to 1500°C and the resulting fritted glasses were heat treated at 900°C. The starting materials and the mixtures thereof were characterized before and after thermal treatment by differential thermal analysis, X-ray diffraction and fluorescence, and scanning electron microscopy. The results obtained showed that the WDR is easily incorporated into the glass matrix and causes easy devitrification after short heat treatment periods at low temperature.

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