scholarly journals Nano-Sized Minerals from Lower Cretaceous Sandstones in Israel Observed by Transmission Electron Microscopy (TEM)

2021 ◽  
Author(s):  
Nurit Taitel-Goldman ◽  
Vladimir Ezersky
Keyword(s):  
Clay Minerals ◽  
Iron Oxides ◽  
Lower Cretaceous ◽  
Fine Fraction ◽  
Anatase Tio2 ◽  
Rutile Tio2 ◽  
Transmission Electron ◽  
Quartz Arenite ◽  
Dark Violet ◽  
Hematite Fe2o3

Fine fraction in quartz arenite sandstones from Lower Cretaceous Hatira formation in Israel was observed by Transmission electron microscope (TEM). Samples were collected from Hatira and Ramon craters located in southern part of Israel and from Manara cliff from the northern part of Israel. The additional phases cause yellow, red, dark red and dark violet colors of the layered sandstones. The motivation was to identify the minerals of the fine factions that cause the variations in the colors. The minerals observed were clay minerals, mainly kaolinite (Al4Si4O20(OH)8), some illite (K0.65Al2.0[Al0.65Si3.35O10](OH)2) and smectite. Iron oxides were goethite (FeOOH) and hematite (Fe2O3), Titanium-iron oxides observed was ilmenite (FeTiO3), and Titanium-oxides were rutile (TiO2), and anatase (TiO2). Sulphates observed were jarosite (KFe3(SO4)2(OH)6) and alunite (KAl3(SO4)2(OH)6). Some of the hematite was formed by recrystallization of goethite. Ilmenite disintegrated into small iron oxides mainly hematite. Euhedral to sub-hedral rutile (TiO2) and anatase (TiO2) were preserved in clay-minerals. Crystals of alunite and jarosite were observed in sandstones in both craters. They probably crystallized due to some transgression of the Thetis Sea.

scholarly journals Effects of Recycled Fe2O3 Nanofiller on the Structural, Thermal, Mechanical, Dielectric, and Magnetic Properties of PTFE Matrix

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2332
Author(s):  
Ahmad Mamoun Khamis ◽  
Zulkifly Abbas ◽  
Raba’ah Syahidah Azis ◽  
Ebenezer Ekow Mensah ◽  
Ibrahim Abubakar Alhaji
Keyword(s):  
Electron Microscopy ◽  
High Energy ◽  
Filler Loading ◽  
Complex Permeability ◽  
X Ray Diffraction ◽  
Thermal Expansion Coefficients ◽  
Transmission Electron ◽  
Energy Ball ◽  
Hematite Fe2o3 ◽  
Ptfe Composites

The purpose of this study was to improve the dielectric, magnetic, and thermal properties of polytetrafluoroethylene (PTFE) composites using recycled Fe2O3 (rFe2O3) nanofiller. Hematite (Fe2O3) was recycled from mill scale waste and the particle size was reduced to 11.3 nm after 6 h of high-energy ball milling. Different compositions (5–25 wt %) of rFe2O3 nanoparticles were incorporated as a filler in the PTFE matrix through a hydraulic pressing and sintering method in order to fabricate rFe2O3–PTFE nanocomposites. The microstructure properties of rFe2O3 nanoparticles and the nanocomposites were characterized through X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and high-resolution transmission electron microscopy (HRTEM). The thermal expansion coefficients (CTEs) of the PTFE matrix and nanocomposites were determined using a dilatometer apparatus. The complex permittivity and permeability were measured using rectangular waveguide connected to vector network analyzer (VNA) in the frequency range 8.2–12.4 GHz. The CTE of PTFE matrix decreased from 65.28×10−6/°C to 39.84×10−6/°C when the filler loading increased to 25 wt %. The real (ε′) and imaginary (ε″) parts of permittivity increased with the rFe2O3 loading and reached maximum values of 3.1 and 0.23 at 8 GHz when the filler loading was increased from 5 to 25 wt %. A maximum complex permeability of 1.1−j0.07 was also achieved by 25 wt % nanocomposite at 10 GHz.

scholarly journals Sulfurization of hematite Fe2O3 and anatase TiO2 by annealing in H2S

2019 ◽  
Vol 222 ◽  
pp. 152-158 ◽  
Author(s):  
Woo Jung Shin ◽  
Araceli Hernández Granados ◽  
Wen-Hsi Huang ◽  
Hailin Hu ◽  
Meng Tao
Keyword(s):  
Anatase Tio2 ◽  
Hematite Fe2o3

scholarly journals The Occurrence of Authigenic Clay Minerals in Alkaline-Saline Lakes, Pantanal Wetland (Nhecolândia Region, Brazil)

Minerals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 718
Author(s):  
Isis Armstrong Dias ◽  
Leonardo Fadel Cury ◽  
Bruno Guimarães Titon ◽  
Gustavo Barbosa Athayde ◽  
Guilherme Fedalto ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Clay Minerals ◽  
Saline Lakes ◽  
Clay Fraction ◽  
Water Bodies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Fine Clay ◽  
Pantanal Wetland

Mg clay minerals are usually associated with carbonates in alkaline-saline environments, precipitated from solution and/or transformation from other minerals. The aim of this research is to identify the mineralogy and geochemistry of clay minerals in different alkaline lakes in the Nhecolândia region, the southernmost region of the Pantanal wetland (Brazil). Sediment samples were analyzed by X-ray diffraction, X-ray fluorescence, scanning electron microscopy and transmission electron microscopy. Water samples were analyzed, determining their main cations and anions, in order to understand their relationship with the clays. The analyses allowed classifying the water bodies as saline, oligosaline and freshwater lakes. The sediments are composed mainly of quartz and a fine-clay fraction, dominated by illite, kaolinite and smectite. The XRD results showed illite and smectite mixed-layered in the saline lakes at Barranco Alto farm, whereas at Nhumirim farm, trioctahedral smectite was only observed in one lake. The smectite minerals were normally identified coupled with calcite at the top of the sequences, associated with exopolymeric substances (EPS) in the lakes, suggesting that these minerals are precipitating due to the physical-chemical and biological conditions of the water bodies.

The influence of aluminium on iron oxides: XII. High-resolution transmission electron microscopic (HRTEM) study of aluminous goethites

Clay Minerals ◽  
1985 ◽  
Vol 20 (2) ◽  
pp. 255-262 ◽  
Author(s):  
S. Mann ◽  
R. M. Cornell ◽  
U. Schwertmann
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Iron Oxides ◽  
Dissolution Kinetics ◽  
Electron Microscopic ◽  
Al Substitution ◽  
Transmission Electron ◽  
Transmission Electron Microscopic

Aluminium-substituted goethites are found in many soils and can also be synthesised readily in the laboratory. In recent years, synthetic substituted goethites have been examined by various techniques including XRD, IR, TEM and dissolution kinetics (Thiel, 1963; Jonas & Solymar, 1970; Fey & Dixon, 1981; Fysh & Fredericks, 1983; Schulze & Schwertmann, 1984; Schwertmann, 1984). Transmission electron microscopy (TEM) studies have shown that as Al substitution rises above 10%, the goethite needles become shorter and also thicker in the a direction. Furthermore, crystals which at zero substitution consist of domains parallel to the c axis become less domainic with increasing Al substitution (Schulze & Schwertmann, 1984).

An occurrence of polymorphic halloysite in granite saprolite of the Bayerischer Wald, Germany

Clay Minerals ◽  
1978 ◽  
Vol 13 (1) ◽  
pp. 67-77 ◽  
Author(s):  
B.-M. Wilke ◽  
U. Schwertmann ◽  
E. Murad
Keyword(s):  
Trace Elements ◽  
Clay Minerals ◽  
Iron Oxides ◽  
Aqueous Phase ◽  
Mixed Layer ◽  
Thin Plates ◽  
Low Crystallinity

AbstractXRD, DTA and IR patterns showed clay veins filling fissures in a granite of the Bayerischer Wald (eastern Bavaria) to consist mainly of hydrated halloysite of low crystallinity with traces of gibbsite, 2:1 (mixed layer) clay minerals and iron oxides. The halloysite forms thin plates which exhibit varying degrees and types of enrolment, resulting in platy, tubular and spheroidal crystals within the same sample. Concentrations of the trace elements Rb, Sr, Ba, Zr, Y, Ce, Pb, Zn and Cu indicate halloysite formation to have taken place via an aqueous phase under the influence of vadose waters circulating in fissures.

Thermal study of some manganese oxide minerals

1950 ◽  
Vol 29 (210) ◽  
pp. 239-251 ◽  
Author(s):  
J. Laurence Kulp ◽  
Jose N. Perfetti
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Manganese Oxide ◽  
Clay Minerals ◽  
Iron Oxides ◽  
Theoretical Background ◽  
Thermal Study ◽  
The Past ◽  
Considerable Success ◽  
Oxide Minerals

In the past decade, differential thermal analysis has developed into a very useful mineralogical technique. The theoretical background for this method has been treated by Speil, Berkelhamer, Pask, and Da vies (1945) and has been modified by Kerr and Kulp (1948, 1949). The application of the method to the clay minerals has been carried out with considerable success by a number of workers in Europe and America. In particular, Grim and co-workers (1942, 1947, 1948) have produced a number of significant papers dealing with the thermal analysis of clays. The method has been extended to other mineral groups such as the carbonates (Faust, 1949; Beck, 1946; Kerr and Kulp, 1947; Cuthbert and Rowland, 1947; Kulp, Kent, and Kerr, 1950), phosphates (Manly, 1950), sulphates (Kulp and Adler, 1950), quartz (Faust, 1948), and the hydrous iron oxides (Kulp and Trites, 1950).

Sodium-fluoride pH of South-Western Australian soils as an indicator of P-sorption

Soil Research ◽  
1994 ◽  
Vol 32 (4) ◽  
pp. 755 ◽  
Author(s):  
RJ Gilkes ◽  
JC Hughes
Keyword(s):  
Clay Minerals ◽  
Iron Oxides ◽  
Sorption Capacity ◽  
Sodium Fluoride ◽  
Secondary Importance ◽  
P Sorption ◽  
Soil Constituent ◽  
Western Australian ◽  
Soil Constituents ◽  
Measuring Ph

Phosphate sorption by the surface horizon of 228 acid to neutral Western Australian (W.A.) soils is more closely related (r(2) = 0.76) to the content of oxalate-extractable aluminium than to any other soil constituent. This fraction corresponds to poorly ordered inorganic and organic Al compounds that release considerable amounts of OH- to NaF solution. Thus the abundance of these compounds in soil may be estimated by measurement of the pH of a NaF extract (pH((NaF)) This association enables the rapid and moderately accurate prediction in the field of the P-sorption capacity of soils (r(2) = 0.72) by measuring pH(NaF) With a. simple, portable pH meter. For many W.A. soils, it is probable that well crystalline aluminium and iron oxides, clay minerals and other soil constituents are of secondary importance in determining P-sorption and that most P-sorption is due to poorly ordered and organically complexed forms of Al.

Pathways and Mechanisms for Removal of Dissolved Organic Carbon from Leaf Leachate in Streams

1981 ◽  
Vol 38 (1) ◽  
pp. 68-76 ◽  
Author(s):  
Clifford N. Dahm
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Clay Minerals ◽  
Iron Oxides ◽  
Amorphous Solid ◽  
Microbial Utilization ◽  
Physical Chemical ◽  
Fine Particulate ◽  
Solid Phases ◽  
Aluminum And Iron Oxides

Removal of dissolved organic carbon (DOC) from water resulting from adsorption and microbial uptake was examined to determine the importance of biotic and abiotic pathways. Physical–chemical adsorption to components of the stream sediment or water and biotic assimilation associated with the microbial population was determined in recirculating chambers utilizing leachate from alder (Alnus rubra). Adsorptive mechanisms were further separated into interactions involving (1) specific clay minerals, (2) amorphous solid phases of hydrous aluminum and iron oxides, and (3) fine particulate organic matter. Physical–chemical adsorptive mechanisms for alder leachate removal exhibited rapid kinetic equilibration between the DOC and solid phases, but only a specific fraction of the DOC, likely containing certain chemical functional groups, was adsorbed. The amorphous aluminum and iron oxides possessed a much higher potential capacity than the clay minerals or fine particulate organics for DOC adsorption. Microbial uptake of DOC from the alder leachate was kinetically slower than adsorptive uptake. However, microbial activity was overall much more effective in the removal and degradation of the total DOC pool leached from alder leaves. Over a 48-h period, 97% of added 14C labeled leachate was removed from solution by adsorption (~ 20%) and microbial utilization (~ 77%). The rate of microbial uptake was 45 μg C/g sediment C∙h−1 or 14 mg C∙m−2∙h−1.

scholarly journals Identification of interstratified mica and pyrophyllite monolayers within chlorite using advanced scanning/transmission electron microscopy

2019 ◽  
Vol 104 (10) ◽  
pp. 1436-1443
Author(s):  
Guanyu Wang ◽  
Hejing Wang ◽  
Jianguo Wen
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
Clay Minerals ◽  
Scanning Transmission Electron Microscopy ◽  
Dark Field ◽  
Chemical Compositions ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission

Abstract Interstratified clay minerals reflect the weathering degree and record climatic conditions and the pedogenic processes in the soil. It is hard to distinguish a few layers of interstratified clay minerals from the chlorite matrix, due to their similar two-dimensional tetrahedral-octahedral-tetrahedral (TOT) structure and electron-beam sensitive nature during transmission electron microscopy (TEM) imaging. Here, we used multiple advanced TEM techniques including low-dose high-resolution TEM (HRTEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) imaging combined with energy-dispersive spectroscopic (EDS) mapping to study interstratified layers in a chlo-rite sample from Changping, Beijing, China. We demonstrated an interstratified mica or pyrophyllite monolayer could be well distinguished from the chlorite matrix by projected atomic structures, lattice spacings, and chemical compositions with advanced TEM techniques. Further investigation showed two different transformation mechanisms from mica or pyrophyllite to chlorite: either a 4 Å increase or decrease in the lattice spacing. This characterization approach can be extended to the studies of other electron-beam sensitive minerals.

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