scholarly journals Exploitation of Bentonite for Wastewater Treatment

2021 ◽  
Author(s):  
Kali Abderrahim ◽  
Loulidi Ilyasse ◽  
Amar Abdelouahed ◽  
Boukhlifi Fatima ◽  
Hadey Chaimaa ◽  
...  
Keyword(s):  
Chemical Characterization ◽  
Phenol Adsorption ◽  
Significant Percentage ◽  
Adsorption Study ◽  
The Subject ◽  
Uv Visible ◽  
Xrd Techniques ◽  
Kinetics Of ◽  
Langmuir And Freundlich Models

Bentonite is a clay with interesting surface properties (affinity for water, adsorption capacity for electro-positive compounds….). The characteristics and clarifying properties of bentonite from various companies are the subject of numerous studies. The present work focuses on the study of the efficiency of bentonite and modified bentonite to purify aqueous solutions containing organic pollutants such as phenol. First, before starting the adsorption study, a physical–chemical characterization of the clay by FTIR, BET and XRD techniques was undertaken. The specific surface of the bentonite is calculated by BET. Then, the study of isotherms and kinetics of phenol adsorption on commercial BTC showed that this pollutant can be removed from liquid effluents with a significant percentage. Langmuir and Freundlich models were applied. Finally, the kinetic study performed by UV–Visible was reproduced by FTIR spectroscopy.

Characterization of Nanocrystalline γ–Fe2O3Prepared by Wet Chemical Method

1999 ◽  
Vol 14 (4) ◽  
pp. 1570-1575 ◽  
Author(s):  
G. Ennas ◽  
G. Marongiu ◽  
A. Musinu ◽  
A. Falqui ◽  
P. Ballirano ◽  
...  
Keyword(s):  
Isothermal Treatment ◽  
X Ray Diffraction ◽  
Ferrous Chloride ◽  
Scanning Calorimetry ◽  
Direct Transformation ◽  
X Ray ◽  
Transmission Electron ◽  
Xrd Techniques ◽  
Kinetics Of

Homogeneous maghemite (γ–Fe2O3) nanoparticles with an average crystal size around 5 nm were synthesized by successive hydrolysis, oxidation, and dehydration of tetrapyridino-ferrous chloride. Morphological, thermal, and structural properties were investigated by transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and x-ray diffraction (XRD) techniques. Rietveld refinement indicated a cubic cell. The superstructure reflections, related to the ordering of cation lattice vacancies, were not detected in the diffraction pattern. Kinetics of the solid-state phase transition of nanocrystalline maghemite to hematite (α–Fe2O3), investigated by energy dispersive x-ray diffraction (EDXRD), indicates that direct transformation from nanocrystalline maghemite to microcrystalline hematite takes place during isothermal treatment at 385 °C. This temperature is lower than that observed both for microcrystalline maghemite and for nanocrystalline maghemite supported on silica.

Bias of the paleobotanical record as a consequence of variations in the chemical composition of higher vascular plant cuticles

Paleobiology ◽  
1991 ◽  
Vol 17 (2) ◽  
pp. 133-144 ◽  
Author(s):  
Erik W. Tegelaar ◽  
Hans Kerp ◽  
Henk Visscher ◽  
Pieter A. Schenck ◽  
Jan W. de Leeuw
Keyword(s):  
Chemical Composition ◽  
Higher Plants ◽  
Vascular Plant ◽  
Chemical Characterization ◽  
Pyrolysis Gas ◽  
Plant Cuticles ◽  
The Subject ◽  
The Impact ◽  
Curie Point Pyrolysis

The impact of the variations in the chemical composition of higher vascular plant cuticles on their fossil record is usually not considered in paleobotanical and, more particularly, taphonomic studies. Here we address the subject with reference to the chemical characterization of insoluble cuticular matrices of a large variety of recent and fossil cuticles. The cuticles were analyzed using Curie-point pyrolysis-gas chromatographic techniques. Cuticular matrices of extant higher plants consist either of the biopolyester cutin, the insoluble, non-hydrolyzable polymethylenic biopolymer cutan, or a mixture of both biopolymers. In fossil cuticles an additional cuticular matrix type consisting of cutan and cutin-derived material is recognized. On the basis of the variations in their chemical composition and the different behavior of the cuticular constituents (viz., cutin and cutan) during diagenesis, it is concluded that the paleobotanical record of cuticles will be biased toward taxa originally having a significant amount of cutan in their cuticular matrix.

scholarly journals Characterization of surface fish-eye casting defect

2013 ◽  
Vol 66 (1) ◽  
pp. 99-103
Author(s):  
Adriano Murilo Rosário ◽  
Marcio Ferreira Hupalo
Keyword(s):  
Defect Formation ◽  
Chemical Characterization ◽  
Casting Defect ◽  
Green Sand ◽  
Cast Irons ◽  
Molding Sand ◽  
The Subject ◽  
Fish Eye ◽  
Ductile Iron Casting

Fish-eye defects are usually observed in the surface of ductile iron casting. Their formation mechanism is not fully understood and very little has been published concerning the subject. This paper investigates the sleeve material effect on fish-eye defect formation in ductile cast irons. Unburnt exothermic and insulating sleeves with different fluorine concentrations have been crushed and mixed in with green sand. These mixtures have been used as facing sands for the casting molds. The morphological and chemical characterization of the fish-eye defects have been performed by light optical microscopy (LOM) and scanning electron microscopy with energy-dispersive spectroscopy (SEM/EDS). Experimental results suggest that surface fish-eye defects on ductile cast irons are caused by the buildup of fluorine-containing sleeve materials in the molding sand.

scholarly journals Cryogenic Examination on Fiber Metal Laminates – A Short Critic

2019 ◽  
Vol 9 (1S4) ◽  
pp. 657-660
Keyword(s):  
Cryogenic Treatment ◽  
Chemical Characterization ◽  
Material Behavior ◽  
Heat Absorption ◽  
Fiber Metal Laminates ◽  
Materials Development ◽  
Physical Chemical ◽  
The Subject ◽  
Fiber Metal

Fiber Metal laminates (FML) have made its place in the prominence of the materials development whereby the study of its mechanical, physical, chemical characterization of the property of the material behavior have been studies and reported by various intellects. This paper delivers a scope of cryogenic treatment and the effect of the Fiber Metal laminates towards its property change and dialect behavior towards the subject of the material to the adverse cooling temperature. Every material holds a particular energy by its stances to the heat of addition which results due cause of the material heat absorption and quantum movement of the particles resulting in the energy due cause of molecular randomness.

scholarly journals Mediation of Elicitin Activity on Tobacco Is Assumed by Elicitin-Sterol Complexes

2001 ◽  
Vol 12 (9) ◽  
pp. 2825-2834 ◽  
Author(s):  
Hanan Osman ◽  
Sébastien Vauthrin ◽  
Vladimir Mikes ◽  
Marie-Louise Milat ◽  
Franck Panabières ◽  
...  
Keyword(s):  
Binding Sites ◽  
Defense Mechanisms ◽  
Specific Binding ◽  
Biological Effects ◽  
Chemical Characterization ◽  
Site Directed Mutagenesis ◽  
Specific Binding Sites ◽  
Biological Responses ◽  
Kinetics Of

Elicitins secreted by phytopathogenic Phytophthoraspp. are proteinaceous elicitors of plant defense mechanisms and were demonstrated to load, carry, and transfer sterols between membranes. The link between elicitor and sterol-loading properties was assessed with the use of site-directed mutagenesis of the 47 and 87 cryptogein tyrosine residues, postulated to be involved in sterol binding. Mutated cryptogeins were tested for their ability to load sterols, bind to plasma membrane putative receptors, and trigger biological responses. For each mutated elicitin, the chemical characterization of the corresponding complexes with stigmasterol (1:1 stoichiometry) demonstrated their full functionality. However, these proteins were strongly altered in their sterol-loading efficiency, specific binding to high-affinity sites, and activities on tobacco cells. Ligand replacement experiments strongly suggest that the formation of a sterol-elicitin complex is a requisite step before elicitins fasten to specific binding sites. This was confirmed with the use of two sterol-preloaded elicitins. Both more rapidly displaced labeled cryptogein from its specific binding sites than the unloaded proteins. Moreover, the binding kinetics of elicitins are related to their biological effects, which constitutes the first evidence that binding sites could be the biological receptors. The first event involved in elicitin-mediated cell responses is proposed to be the protein loading with a sterol molecule.

Irradiation behavior of pyrolytic silicon carbide

1983 ◽  
Vol 41 ◽  
pp. 72-73
Author(s):  
R. J. Lauf
Keyword(s):  
Silicon Carbide ◽  
Fission Products ◽  
Thermodynamics And Kinetics ◽  
Neutron Fluences ◽  
Fuel Particles ◽  
Sic Coatings ◽  
Irradiation Behavior ◽  
Kinetics Of ◽  
Htgr Fuel

Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain a layer of pyrolytic silicon carbide to act as a miniature pressure vessel and primary fission product barrier. Optimization of the SiC with respect to fuel performance involves four areas of study: (a) characterization of as-deposited SiC coatings; (b) thermodynamics and kinetics of chemical reactions between SiC and fission products; (c) irradiation behavior of SiC in the absence of fission products; and (d) combined effects of irradiation and fission products. This paper reports the behavior of SiC deposited on inert microspheres and irradiated to fast neutron fluences typical of HTGR fuel at end-of-life.

Olfactory and Chemical Characterization of Indoor Air-Towards a Psychophysical Model for Air Quality

1981 ◽  
Author(s):  
Birgitta Berglund ◽  
Ulf Berglund ◽  
Thomas Lindvall ◽  
Helene Nicander-Bredberg
Keyword(s):  
Air Quality ◽  
Indoor Air ◽  
Chemical Characterization
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