Synthesis of high purity Li8SiO6 using a citric acid-assisted route

Rice husks (RH) are agricultural wastes available abundantly in rice producing country. A by-product obtained from combustion of rice husk is rice husk ash (RHA) which is rich in silica (SiO2) contents. This paper focused on the effect of acid leaching treatment on rice husk to produce high-purity silica. There are 4 different states of conditions involved; raw rice husk (RRH), treated rice husk (TRH), rice husk ash (RHA), and treated rice husk ash (TRHA). Citric acid; C6H8O7 was used as a leaching agent. TRH and TRHA was leached to see whether treated rice husk before combustion (TRH) or treated rice husk after combustion (TRHA) will produce more high-purity silica. Chemical composition analysis shows high amorphous silica content which is 98.47% with low metallic impurities at 1.0M C6H8O7, 70 oC for treated rice husk (TRH). X-ray diffraction (XRD) pattern shows the presence of amorphous silica in treated rice husk (TRH) and crystalline silica in treated rice husk ash (TRHA). Fragmentation of TRH into small pieces after acid leaching is seen where there is significant increase in the exposed surface areas. High-purity amorphous silica with more than 98% was prepared via citric acid leaching treatment and combustion process.

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Synthesis of high-purity (CaxLa1.00−x)(Ba1.75−xLa0.25+x)Cu3Oz tetragonal superconductor by an aqueous solution technique using citric acid

Physica C Superconductivity ◽

10.1016/s0921-4534(01)00226-x ◽

2001 ◽

Vol 357-360 ◽

pp. 260-264 ◽

Cited By ~ 6

Author(s):

Yasushi Sato ◽

Masato Kakihana ◽

Valery Petrykin ◽

Minoru Osada ◽

Hiroshi Yasuoka ◽

...

Keyword(s):

Aqueous Solution ◽

Citric Acid ◽

High Purity ◽

Solution Technique

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The Effect of Pyrolysis Conditions on the Preparation of Fe2O3 Particles Using Simulated Pickling Liquor in a Venturi Reactor

Frontiers in Materials ◽

10.3389/fmats.2021.733257 ◽

2021 ◽

Vol 8 ◽

Author(s):

Chao Lv ◽

Ming-He Sun ◽

Hong-Xin Yin

Keyword(s):

Particle Size ◽

Citric Acid ◽

Particle Size Distribution ◽

Numerical Simulations ◽

High Purity ◽

Maximum Concentration ◽

Pyrolysis Temperature ◽

Iron And Steel ◽

Physical Experiments ◽

Acid Ratio

Large amounts of pickling liquor are produced during the pickling of iron and steel. The Venturi reactor is used during the pyrolysis of pickling liquor to prepare high-purity Fe2O3 particles. Changing the pyrolysis conditions will affect the purity and concentration of Fe2O3 particles. In this paper, physical experiments and numerical simulations were carried out to study the effect of pyrolysis conditions on the Fe2O3 particles, including the pyrolysis temperature, the FeCl2/FeCl3 ratio in the pickling liquor, and the citric acid ratio. The results showed that a product with a higher purity, better crystallinity, and greater concentration was obtained at 923 K. Further increasing the temperature did not change the concentration of Fe2O3 particles. When the ratio of FeCl2/FeCl3 in the pickling liquor was 1:1.5, the maximum concentration of Fe2O3 particles at the outlet was obtained. When the added proportion of citric acid was 1:1, the particle size distribution was more uniform, and when the added proportion was 1:2.5, the maximum concentration of Fe2O3 particles at the outlet was achieved.

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Optimization and Preliminary Physicochemical Characterization of Pectin Extraction from Watermelon Rind (Citrullus lanatus) with Citric Acid

International Journal of Food Science ◽

10.1155/2022/3068829 ◽

2022 ◽

Vol 2022 ◽

pp. 1-10

Author(s):

José Pérez ◽

Karina Gómez ◽

Lorena Vega

Keyword(s):

Citric Acid ◽

High Purity ◽

Acid Content ◽

Physicochemical Characterization ◽

Extraction Time ◽

Significant Variable ◽

Optimal Conditions ◽

Degree Of Esterification ◽

Solid Ratio ◽

Watermelon Rind

Watermelon rind was used for the pectin extraction with citric acid as the extractant solvent. The effects of pH (2.0-3.0), extraction time (45-75 min), and liquid-solid ratio (10 : 1 to 40 : 1 mL/g) on the pectin yield, degree of esterification, methoxyl content, and anhydrouronic acid content were investigated using Box-Behnken surface response experimental design. The pH was the most significant variable for the pectin yield and properties. The responses optimized separately showed different optimal conditions for each one of the variables studied in this work. Therefore, the desirability function was used to determine the sole theoretical optimum for the highest pectin yield and highest anhydrouronic acid content, which was found to be pH of 2.0, extraction time of 62.31 min, and liquid-solid ratio of 35.07 mL/g. Under this optimal condition, the pectin yield, degree of esterification, methoxyl content, and anhydrouronic acid content were 24.30%, 73.30%, 10.45%, and 81.33%, respectively. At optimal conditions, watermelon rind pectin can be classified as high methoxyl and rapid-set pectin with high quality and high purity. Practical Applications. This study evaluated the pectin extraction from watermelon rind and carried out an optimization of multiple responses as a function of pH, time, and liquid-solid ratio to obtain the best preliminary quality parameters (pectin yield and anhydrouronic acid content). The results revealed that watermelon rind waste can be an inexpensive source to obtain good pectin quality and high purity. According to the chemical characterization and physicochemical properties studied, the extracted pectin from watermelon rind would have a high potential to be used in food industry.

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A Novel Route for Agarooligosaccharide Production with the Neoagarooligosaccharide-Producing β-Agarase as Catalyst

Catalysts ◽

10.3390/catal10020214 ◽

2020 ◽

Vol 10 (2) ◽

pp. 214 ◽

Cited By ~ 2

Author(s):

Chengcheng Jiang ◽

Zhen Liu ◽

Jianan Sun ◽

Changhu Xue ◽

Xiangzhao Mao

Keyword(s):

Citric Acid ◽

High Purity ◽

Value Added ◽

High Specificity

Enzymes are catalysts with high specificity. Different compounds could be produced by different enzymes. In case of agaro-oligosaccharides, agarooligosaccharide (AOS) can be produced by α-agarase through cleaving the α-1,3-glycosidic linkages of agarose, while neoagarooligosaccharide (NAOS) can be produced by β-agarase through cleaving the β-1,4-glycosidic linkages of agarose. However, in this study, we showed that β-agarase could also be used to produce AOSs with high purity and yield. The feasibility of our route was confirmed by agarotriose (A3) and agaropentaose (A5) formation from agaroheptaose (A7) and agarononoses (A9) catalyzed by β-agarase. Agarose was firstly liquesced by citric acid into a mixture of AOSs. The AOSs mixture was further catalyzed by β-agarase. When using the neoagarotetraose-forming β-agarase AgWH50B, agarotriose could be produced with the yield of 48%. When using neoagarotetraose, neoagarohexaose-forming β-agarase DagA, both agarotriose and agaropentaose could be produced with the yield of 14% and 13%, respectively. Our method can be used to produce other value-added agaro-oligosaccharides from agarose by different agarolytic enzymes.

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Observations oh Nucleation and Growth of Voids in Nickel

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069065 ◽

1970 ◽

Vol 28 ◽

pp. 414-415

Author(s):

J. L. Brimhall ◽

H. E. Kissinger ◽

B. Mastel

Keyword(s):

High Purity ◽

Growth Stage ◽

Elevated Temperatures ◽

Early Growth ◽

Nucleation And Growth ◽

Pure Nickel ◽

Different Temperatures ◽

Total Fluence ◽

Neutron Exposure ◽

Growth Of Voids

Some information on the size and density of voids that develop in several high purity metals and alloys during irradiation with neutrons at elevated temperatures has been reported as a function of irradiation parameters. An area of particular interest is the nucleation and early growth stage of voids. It is the purpose of this paper to describe the microstructure in high purity nickel after irradiation to a very low but constant neutron exposure at three different temperatures.Annealed specimens of 99-997% pure nickel in the form of foils 75μ thick were irradiated in a capsule to a total fluence of 2.2 × 1019 n/cm2 (E > 1.0 MeV). The capsule consisted of three temperature zones maintained by heaters and monitored by thermocouples at 350, 400, and 450°C, respectively. The temperature was automatically dropped to 60°C while the reactor was down.

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Preparation and characterisation of vanadium pentoxide supported rhodium catalyst

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010010679x ◽

1988 ◽

Vol 46 ◽

pp. 946-947

Author(s):

A. Legrouri

Keyword(s):

Aqueous Solution ◽

Thermal Decomposition ◽

Physicochemical Properties ◽

Surface Area ◽

Vanadium Pentoxide ◽

High Purity ◽

Gas Adsorption ◽

Rhodium Catalyst ◽

Optical Methods ◽

Reducible Oxides

The industrial importance of metal catalysts supported on reducible oxides has stimulated considerable interest during the last few years. This presentation reports on the study of the physicochemical properties of metallic rhodium supported on vanadium pentoxide (Rh/V2O5). Electron optical methods, in conjunction with other techniques, were used to characterise the catalyst before its use in the hydrogenolysis of butane; a reaction for which Rh metal is known to be among the most active catalysts.V2O5 powder was prepared by thermal decomposition of high purity ammonium metavanadate in air at 400 °C for 2 hours. Previous studies of the microstructure of this compound, by HREM, SEM and gas adsorption, showed it to be non— porous with a very low surface area of 6m2/g3. The metal loading of the catalyst used was lwt%Rh on V2Q5. It was prepared by wet impregnating the support with an aqueous solution of RhCI3.3H2O.

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High-purity Ge x-ray detectors: Sensitivity factors and usefulness

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100136350 ◽

1990 ◽

Vol 48 (2) ◽

pp. 548-548

Author(s):

E. B. Steel

Keyword(s):

High Purity ◽

High Energy ◽

Quantitative Chemical Analysis ◽

Detector Performance ◽

X Ray ◽

Detector Sensitivity ◽

Specimen Holder ◽

Many Instruments ◽

Charge Resolution ◽

Sensitivity Factors

High Purity Germanium (HPGe) x-ray detectors are now commercially available for the analytical electron microscope (AEM). The detectors have superior efficiency at high x-ray energies and superior resolution compared to traditional lithium-drifted silicon [Si(Li)] detectors. However, just as for the Si(Li), the use of the HPGe detectors requires the determination of sensitivity factors for the quantitative chemical analysis of specimens in the AEM. Detector performance, including incomplete charge, resolution, and durability has been compared to a first generation detector. Sensitivity factors for many elements with atomic numbers 10 through 92 have been determined at 100, 200, and 300 keV. This data is compared to Si(Li) detector sensitivity factors.The overall sensitivity and utility of high energy K-lines are reviewed and discussed. Many instruments have one or more high energy K-line backgrounds that will affect specific analytes. One detector-instrument-specimen holder combination had a consistent Pb K-line background while another had a W K-line background.

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TEM characterization of WSix films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100171973 ◽

1994 ◽

Vol 52 ◽

pp. 848-849

Author(s):

V. C. Kannan ◽

S. M. Merchant ◽

R. B. Irwin ◽

A. K. Nanda ◽

M. Sundahl ◽

...

Keyword(s):

Integrated Circuits ◽

Vapor Deposition ◽

High Purity ◽

Physical Vapor Deposition ◽

Thermal Treatments ◽

Rapid Thermal Anneal ◽

Tungsten Silicide ◽

Tem Characterization ◽

Metal Silicides

Metal silicides such as WSi2, MoSi2, TiSi2, TaSi2 and CoSi2 have received wide attention in recent years for semiconductor applications in integrated circuits. In this study, we describe the microstructures of WSix films deposited on SiO2 (oxide) and polysilicon (poly) surfaces on Si wafers afterdeposition and rapid thermal anneal (RTA) at several temperatures. The stoichiometry of WSix films was confirmed by Rutherford Backscattering Spectroscopy (RBS). A correlation between the observed microstructure and measured sheet resistance of the films was also obtained.WSix films were deposited by physical vapor deposition (PVD) using magnetron sputteringin a Varian 3180. A high purity tungsten silicide target with a Si:W ratio of 2.85 was used. Films deposited on oxide or poly substrates gave rise to a Si:W ratio of 2.65 as observed by RBS. To simulatethe thermal treatments of subsequent processing procedures, wafers with tungsten silicide films were subjected to RTA (AG Associates Heatpulse 4108) in a N2 ambient for 60 seconds at temperatures ranging from 700° to 1000°C.

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