scholarly journals Modified preparation, and characteristic of vermiculite as catalysts support for catalytic pyrolysis

2021 ◽  
Vol 271 ◽  
pp. 04009
Author(s):  
Yiqian Wang ◽  
Zhipeng Sun
Keyword(s):  
Layered Structure ◽  
Acid Treatment ◽  
Catalytic Pyrolysis ◽  
Pore Diameter ◽  
Catalyst Support ◽  
Natural Sample ◽  
Characteristic Peak ◽  
Chemical Methods ◽  
Complete Structure ◽  
Layered Catalyst

Natural vermiculite, used as layered catalyst support, was modified with different chemical methods, such as acid treatment, introducing into Na+ and organic modification. The vermiculite-based catalysts were characterized by SEM, BET and XRD respect to their images, textures and structures. SEM results presented big pieced of lamellate vermiculite which had complete structure and piled tightly, and the expansion of layer of modified vermiculites. According to XRD results, it had been found that a characteristic peak appeared at 2° compared with natural vermiculite, and the spacing of layers of the modified samples increased obviously. These results corresponded with BET results which modified vermiculites had larger surface area and pore diameter than natural sample. It meant that modification was beneficial to broaden layered structure and modified vermiculites had the potential as catalyst support.

Ceramic Membrane Made of Alumina Synthesized by Pechini Method for Application in Microfiltration Processes

2015 ◽  
Vol 820 ◽  
pp. 79-83 ◽  
Author(s):  
Mirele Costa da Silva ◽  
Francisco Nilson da Silva ◽  
Hélio de Lucena Lira ◽  
Normanda Lino de Freitas
Keyword(s):  
Total Mass ◽  
Pore Diameter ◽  
Ceramic Membrane ◽  
Pechini Method ◽  
Mercury Porosimetry ◽  
Ceramic Membranes ◽  
Chemical Methods ◽  
Average Pore ◽  
Total Mass Loss ◽  
Alpha Alumina

Given the diversity of areas in which applications of ceramic membranes are included, the literature has shown great interest of researchers to obtain these materials with powders synthesized by different chemical methods. Thus, this work aims at the synthesis of alumina by Pechini method, the 2:1 ratio of citric acid: metal cations, calcined to 1100°C, to obtain membranes. The synthesized powders were characterized by thermal analysis, XRD and particle size distribution, since the membranes were characterized by SEM and mercury porosimetry. The results for the obtained powders showed total mass loss of 61.60%, an alpha-alumina phase with crystallite size of 45.2 nm. As for the membranes, these showed heterogeneously distributed particles with different sizes and irregular geometry, reaching average pore diameter of 0.6 μm me 47% porosity, and thus are characterized for application in microfiltration processes.

scholarly journals AMORPHOUS SILICA OBTAINED FROM NEPHELINE RAW MATERIALS IN THE DEPHOSPHORIZATION OF MUNICIPAL WASTEWATER

2021 ◽  
Vol 26 (2) ◽  
pp. 22-29
Author(s):  
N. V. Fokina ◽  
◽  
D. V. Mayorov ◽  
T. T. Gorbacheva ◽  
◽  
...  
Keyword(s):  
Sorption Capacity ◽  
Amorphous Silica ◽  
Phosphorus Removal ◽  
Acid Treatment ◽  
Municipal Wastewater ◽  
Pore Diameter ◽  
Raw Materials ◽  
Sewage Treatment ◽  
Sewage Treatment Plants ◽  
Fertilizing Effect

Introduction. The paper addresses the importance of extracting the labile form of phosphorus from wastewater with the possibility of its further use. The advantages of sorption methods and the prospects of using amorphous silica as an ameliorant with a prolonged fertilizing effect are considered. Methods. We performed experimental modeling of phosphates extraction from model solutions and a sludge mixture from regional sewage treatment plants. Amorphous silica obtained from local nepheline raw materials in acid treatment using a patented technology was used as sorbents. Results. A sorbent based on amorphous silica with a pore diameter of 8.41 nm was obtained. Its sorption capacity exceeds 29 mgP/g in the phosphate form, which corresponds to the average level of phosphorus removal, noted for a number of sorbents used in the international practice of wastewater dephosphorization when producing unconventional ameliorants. Conclusion. For effective phosphorus removal from municipal wastewater to obtain an unconventional ameliorant with a fertilizing effect in terms of Si and P, sorbent consumption of 1 g/l is sufficient.

scholarly journals Catalytic Pyrolysis of Waste Plastics into Liquid Hydrocarbon using Mesoporous Kaolin Clay

2020 ◽  
Vol 44 (1) ◽  
pp. 1-12
Author(s):  
Mahmudur Rahman ◽  
Subrata Chandra Roy ◽  
Md Mizanul Hassan ◽  
Bijoy Kumar Mondal ◽  
Muhammad Omar Faruk ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Acid Treatment ◽  
Catalytic Pyrolysis ◽  
Nitrogen Adsorption ◽  
Mesoporous Structure ◽  
Liquid Hydrocarbon ◽  
Gas Chromatography Mass Spectrometry ◽  
Feed Ratio ◽  
Kaolin Clay ◽  
Waste Plastics

Catalytic pyrolysis of waste plastics into liquid hydrocarbon was conducted in a locally-made stainless steel reactor. Mesoporous kaolin clay treated with sulfuric acid in the concentration range of 3-7 M was used as a catalyst and waste polyethylene was the plastic feed. The X-ray powder diffraction (XRPD) pattern showed that the raw kaolin clay is crystalline. However, XRPD patterns of H2SO4 acid treated kaolin and Ni and Ru metal impregnated H2SO4 treated kaolin did not exhibit any characteristic diffraction peaks of kaolin. The acid treatment of kaolin causes leaching of Al3+ and results in disintegration of layered structure of kaolin, leading to the formation of Al2(SO4)3, SiO2, and amorphous phase. After 5 M H2SO4 acid treatment, the content of Al2O3 decreased significantly to 18.62%. The Si/Al ratio and specific surface area were found to increase after 5 M sulfuric acid treatment from 1.79 to 3.48 and 6.85 m2/g to 17.92 m2/g, respectively. The nitrogen adsorption-desorption isotherms of the 5 M H2SO4 acid treated kaolin clay showed the isotherm to be of type IV typical for mesoporous structure. Among 3, 5, and 7 M H2SO4 treated kaolin catalysts, the 3 M H2SO4 treated kaolin (at a catalyst to plastic feed ratio of 1:5) exhibited the highest activity with the yield of 83% liquid hydrocarbon. The Ru- and Ni-impregnated 5 M H2SO4 treated kaolin catalyst provided 76% and 79% yield, respectively of liquid hydrocarbon at a catalyst to plastic ratio of 1:5. The gas chromatography-mass spectrometry (GC-MS), 1H NMR, and FTIR spectral analysis confirmed the presence of linear and branched alkanes and alkenes (C9-C20) in the end product obtained with 5 M H2SO4 treated kaolin catalyst. The produced liquid hydrocarbon was found to be free from aromatic compounds importantly polycyclic aromatic hydrocarbons which are potent mutagenic and carcinogenic. Journal of Bangladesh Academy of Sciences, Vol. 44, No. 1, 1-12, 2020

The Influences of Chemical and Mechanical Treatment on the Morphology of Carbon Nanofibers

2017 ◽  
Vol 264 ◽  
pp. 107-111 ◽  
Author(s):  
Norshafiqah Mohamad Saidi ◽  
Noor Azilah Mohd Kasim ◽  
Mohd Junaedy Osman ◽  
Nurjahirah Janudin ◽  
Imran Syakir Mohamad ◽  
...  
Keyword(s):  
Carbon Nanofibers ◽  
Acid Treatment ◽  
Functional Group ◽  
Aqueous Media ◽  
Structural Defects ◽  
Outer Diameter ◽  
Oxygen Functional Group ◽  
Mechanical Method ◽  
Chemical Methods ◽  
Experiment Method

Oxidation by acid treatment is one of the chemical methods used to introduce surface oxygen functional group (SOFG) and defects on the surface of carbon nanofibers (CNFs). Therefore, many researchers used this method to improve the dispersion ability of CNFs in aqueous media. However, only few researchers used combination of chemical and mechanical method for oxidation of CNFs. In this work, as-received CNFs were treated using chemical method with an addition of mechanical method. On the first experiment (Method A) concentrated sulphuric acid and nitric acid were used and followed by combinations of mechanical method using ultrasonication water bath under reflux. The addition mechanical method through reflux was eliminated and different times of ultrasonication were used in method B and method C. Outer diameter of each CNFs samples were determined from FESEM images and were found to be in range of 50 nm–190 nm. Whereas, Raman spectroscopy was used to analyse any structural defects of CNFs samples during each treatment methods. From the findings, acid treatment of CNFs with addition of mechanical method using ultrasonication showed remarkably effect on the CNFs morphology.

Transmission Electron Microscopy of Protein Macromolecules

1971 ◽  
Vol 29 ◽  
pp. 424-425
Author(s):  
Henry S. Slayter
Keyword(s):  
Biological Systems ◽  
Metal Vapor ◽  
Resolving Power ◽  
Electron Microscopic ◽  
Chemical Methods ◽  
Molecular Weights ◽  
The Past ◽  
Physical Chemical ◽  
Transmission Electron

Electron microscopic methods have been applied increasingly during the past fifteen years, to problems in structural molecular biology. Used in conjunction with physical chemical methods and/or Fourier methods of analysis, they constitute powerful tools for determining sizes, shapes and modes of aggregation of biopolymers with molecular weights greater than 50, 000. However, the application of the e.m. to the determination of very fine structure approaching the limit of instrumental resolving power in biological systems has not been productive, due to various difficulties such as the destructive effects of dehydration, damage to the specimen by the electron beam, and lack of adequate and specific contrast. One of the most satisfactory methods for contrasting individual macromolecules involves the deposition of heavy metal vapor upon the specimen. We have investigated this process, and present here what we believe to be the more important considerations for optimizing it. Results of the application of these methods to several biological systems including muscle proteins, fibrinogen, ribosomes and chromatin will be discussed.

Fasciaton of Pectate Elementary Fibrils

1973 ◽  
Vol 31 ◽  
pp. 60-61
Author(s):  
George F. Leeper
Keyword(s):  
Acid Treatment ◽  
Carbon Film ◽  
Final Concentration ◽  
Cellulose Microfibrils ◽  
Pectic Acid ◽  
Elementary Fibrils

Polysaccharide elementary fibrils are usually fasciated into microfibrils of from one hundred to a few hundred Angstroms wide. Cellulose microfibrils when subjected to acid treatment dissociate into component elementary fibrils. For pectic acid it was observed that variations in pH could cause a change in the fasciation of the elementary fibrils.Solutions of purified pectic acid and sodium phosphotungtate were adjusted to various pH levels with NaOH or HCl and diluted to give a final concentration of 0.5 and 1% for the polysaccharide and negative stains respectively. Micrographs were made of the samples after drying on a carbon film covered grid. The average number of elementary fibrils was determined by counting the number of elementary fibrils in each fascicle intersected by lines drawn across the micrograph.

Sem and X-Ray Analysis of Renal and Biliary Calculi

1976 ◽  
Vol 34 ◽  
pp. 306-307
Author(s):  
R. J. Narconis ◽  
G. L. Johnson
Keyword(s):  
Chemical Constituents ◽  
Natural State ◽  
X Ray Diffraction ◽  
Chemical Methods ◽  
X Ray ◽  
Additional Dimension ◽  
Biliary Calculi ◽  
Calculus Formation ◽  
Scanning Electron

Analysis of the constituents of renal and biliary calculi may be of help in the management of patients with calculous disease. Several methods of analysis are available for identifying these constituents. Most common are chemical methods, optical crystallography, x-ray diffraction, and infrared spectroscopy. The application of a SEM with x-ray analysis capabilities should be considered as an additional alternative.A scanning electron microscope equipped with an x-ray “mapping” attachment offers an additional dimension in its ability to locate elemental constituents geographically, and thus, provide a clue in determination of possible metabolic etiology in calculus formation. The ability of this method to give an undisturbed view of adjacent layers of elements in their natural state is of advantage in determining the sequence of formation of subsequent layers of chemical constituents.

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