scholarly journals Smectite clay minerals reduce the acute toxicity of quaternary alkylammonium compounds towards potentially pathogenic bacterial taxa present in manure and soil

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Benjamin Justus Heyde ◽  
Stefanie P. Glaeser ◽  
Linda Bisping ◽  
Kristin Kirchberg ◽  
Rüdiger Ellinghaus ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cationic Surfactants ◽  
Interlayer Space ◽  
Toxicity Tests ◽  
High Temporal Resolution ◽  
Minimal Inhibitory Concentrations ◽  
Layer Silicates ◽  
Transmission Electron ◽  
Agricultural Applications ◽  
Low Charge

Abstract Quaternary alkylammonium compounds (QAACs) are a group of cationic surfactants which are disinfectants with numerous industrial and agricultural applications and frequently released into the environment. One recent hypothesis is that bacteria present in soil will be protected from acute toxic effects of QAACs in the presence of expandable layer silicates due to interlayer sorption. We therefore studied bacterial growth kinetics with high temporal resolution and determined minimal inhibitory concentrations (MICs) of two QAACs, benzyldimethyldodecylammonium chloride (BAC-C12) and didecyldimethylammonium chlorid (DADMAC-C10), for eight strains of different bacterial taxa (Escherichia coli, Acinetobacter, Enterococcus faecium, Enterococcus faecalis, and Pseudomonas fluorescens) in relation to QAAC sorption to smectite and kaolinite. The MICs of BAC-C12 and DADMAC-C10 were in the absence of smectite and kaolinite in the order of 10 to 30 µg mL−1 and 1.0 to 3.5 µg mL−1 for all strains except the more sensitive Acinetobacter strain. For all tested strains and both tested QAACs, the presence of smectite increased apparent MIC values while kaolinite had no effect on MICs. Sorption curves without bacteria showed that smectite sorbed larger amounts of QAACs than kaolinite. Correcting nominal QAAC concentrations employed in toxicity tests for QAAC sorption using the sorption curves explained well the observed shifts in apparent MICs. Transmission electron microscopy (TEM) demonstrated that the interlayer space of smectite expanded from 13.7 ± 1 Å to 19.9 ± 1.5 Å after addition of BAC-C12. This study provides first evidence that low charge 2:1 expandable layer silicates can play an important role for buffering QAAC toxicity in soils.

scholarly journals Mechanical Activation of Smectite-Based Nanocomposites for Creation of Smart Fertilizers

2022 ◽  
Vol 12 (2) ◽  
pp. 809
Author(s):  
Maxim Rudmin ◽  
Santanu Banerjee ◽  
Boris Makarov ◽  
Kanipa Ibraeva ◽  
Alexander Konstantinov
Keyword(s):  
Electron Microscopy ◽  
Interlayer Space ◽  
Soil Leaching ◽  
X Ray Diffraction ◽  
Activation Time ◽  
Release Rates ◽  
X Ray ◽  
Weight Losses ◽  
Transmission Electron ◽  
Scanning Electron

This research presents the mechanical creation of smart fertilizers from a mixture of smectite and urea in a 3:2 ratio by using the planetary milling technique. The smectite–urea composites show intercalation between urea and mineral, which increases steadily with increasing activation time. A shift of X-Ray Diffraction basal reflections, intensities of Fourier transform infrared spectroscopy (FTIR) peaks, and weight losses in thermogravimetric analysis (TG) document the systematic crystallo-chemical changes of the composites related to nitrogen interaction with activation. Observations of the nanocomposites by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) corroborate the inference. Nitrogen intercalates with smectite in the interlayer space and remains absorbed either within micro-aggregates or on the surface of activated smectites. Soil leaching tests reveal a slower rate of nitrogen than that of traditional urea fertilizers. Different forms of nitrogen within the composites cause their differential release rates to the soil. The formulated nanocomposite fertilizer enhances the quality and quantity of oat yield.

Exsolution and hydration of pyroxenes from partially serpentinized harzburgites

2005 ◽  
Vol 69 (4) ◽  
pp. 491-507 ◽  
Author(s):  
C. Viti ◽  
M. Mellini ◽  
C. Rumori
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Hydration Process ◽  
Stability Field ◽  
Layer Silicates ◽  
Second Stage ◽  
Transmission Electron ◽  
Mixed Layers

AbstractOrtho- and clinopyroxenes within partially-hydrated harzburgites from Elba and Val di Cecina (Italy) show lamellar exsolution textures and variable replacement by biopyriboles, talc-chlorite-serpentine mixed layers and serpentine. Chemical and geothermometric data suggest that the pyroxenes crystallized at 1240–1051°C, followed by subsolidus exsolution at slightly lower T (1145–1025°C for clinopyroxene lamellae + orthopyroxene matrix pairs and a 1033–982°C range for orthopyroxene lamellae + clinopyroxene matrix pairs).Investigation by transmission electron microscopy of exsolved enstatite and augite reveals a multistage hydration process. The first stage (highest T, probably in the amphibole stability field) leads to the formation of biopyribole lamellae within exsolved augite, leaving the enstatite matrix unaffected. The second stage (~500–300°C) corresponds to the topotactic replacement of enstatite by layer silicates (talc + chlorite + serpentine, with (001)layer silicates parallel to (100)enstatite). Enstatite is also replaced by randomly oriented, poorly crystalline serpentine. The last hydration stage (<300°C) corresponds to the disappearence of augite and recrystallization of serpentine, leading to completely hydrated bastites with random lizardite lamellae, polygonal serpentine and minor chrysotile.

Synthesis and optical properties of composites based on ZnS nanoparticles embedded in layered magadiite

Clay Minerals ◽  
2013 ◽  
Vol 48 (5) ◽  
pp. 739-748 ◽  
Author(s):  
Yufeng Chen ◽  
Gensheng Yu
Keyword(s):  
Electron Microscopy ◽  
Optical Properties ◽  
Interlayer Space ◽  
Transmission Spectra ◽  
Zns Nanoparticles ◽  
X Ray ◽  
Transmission Electron ◽  
Uv Visible ◽  
Photoluminescence Enhancement ◽  
Properties Of Composites

AbstractComposites based on ZnS nanparticles embedded in layered magadiite were synthesized via a three step process : protonation of Na-magadiite, ion exchange in order to introduce Zn(NH3)42+ in the interlayer space, and addition of Na2S to form ZnS particles in the interlayer space of magadiite. The composites obtained were characterized by X-ray power diffraction (XRD), Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy (SEM-EDS), Transmission Electron Microscopy (TEM), Raman spectroscopy, Photoluminscence spectra (PL), and UV-visible transmission spectra (UV-vis). Results indicated that ZnS nanoparticles embedded in magadiite presented different optical properties and photoluminescence enhancement properties compared with those of uncovered ZnS particles (without host magadiite).

scholarly journals High temporal-resolution scanning transmission electron microscopy using sparse-serpentine scan pathways

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Eduardo Ortega ◽  
Daniel Nicholls ◽  
Nigel D. Browning ◽  
Niels de Jonge
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
High Speed ◽  
Single Particle Tracking ◽  
Limiting Factor ◽  
High Temporal Resolution ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission

AbstractScanning transmission electron microscopy (STEM) provides structural analysis with sub-angstrom resolution. But the pixel-by-pixel scanning process is a limiting factor in acquiring high-speed data. Different strategies have been implemented to increase scanning speeds while at the same time minimizing beam damage via optimizing the scanning strategy. Here, we achieve the highest possible scanning speed by eliminating the image acquisition dead time induced by the beam flyback time combined with reducing the amount of scanning pixels via sparse imaging. A calibration procedure was developed to compensate for the hysteresis of the magnetic scan coils. A combination of sparse and serpentine scanning routines was tested for a crystalline thin film, gold nanoparticles, and in an in-situ liquid phase STEM experiment. Frame rates of 92, 23 and 5.8 s-1 were achieved for images of a width of 128, 256, and 512 pixels, respectively. The methods described here can be applied to single-particle tracking and analysis of radiation sensitive materials.

Spatial Location of Zerovalent Iron Nanoparticles in Montmorillonite

2011 ◽  
Vol 418-420 ◽  
pp. 674-678
Author(s):  
Ming De Fan ◽  
Jiao Hao ◽  
Yuan Zhang ◽  
Gui Dong Jing
Keyword(s):  
Electron Microscopy ◽  
Iron Nanoparticles ◽  
Interlayer Space ◽  
External Surface ◽  
Spatial Location ◽  
Zerovalent Iron ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Zerovalent Iron Nanoparticles

The spatial location of zerovalent iron nanoparticles hybridized with montmorillonite was identified with easily accessible X-ray diffraction, transmission electron microscopy, and element analyses. These hybridized nanoparticles are not intercalated into the interlayer space of clay whereas mainly located on the external surface of clay. This result would be of great importance for the sorption-based applications of these heterostructures.

Fabrication of CaFe2O4 nanofibers via electrospinning method with enhanced visible light photocatalytic activity

2017 ◽  
Vol 10 (05) ◽  
pp. 1750058 ◽  
Author(s):  
Jianmin Wang ◽  
Yunan Wang ◽  
Yinglei Liu ◽  
Song Li ◽  
Feng Cao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Photocatalytic Performance ◽  
Diffuse Reflectance Spectrum ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Transmission Electron ◽  
Electrospinning Method ◽  
Low Charge

CaFe2O4 nanofibers with diameters of about 130[Formula: see text]nm have been fabricated via a facile electrospinning method. The structures, morphologies and optical properties of the obtained CaF2O4 nanofibers have been investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–Visible UV–Vis diffuse reflectance spectrum. The photocatalytic activities of the CaFe2O4 nanofibers are evaluated by the photo-degradation of Methyl orange (MO). The results show that the CaFe2O4 nanofibers (72%) exhibit much higher photocatalytic performance than the CaFe2O4 powders (27%) prepared by conventional method under visible light irradiation. The enhanced photocatalytic performance of CaFe2O4 nanofibers could be attributed to the large surface area, high photogenerated charge carriers density and low charge transfer resistance, as revealed by photoelectrochemical measurement. And fundamentally, it could be attributed to the decreased particle size and the fibrous nanostructure. This work not only provides an efficient way to improve the photocatalytic activity of CaFe2O4, but also provides a new method for preparing materials with nanofibrous structure.

Techniques for Transmission Electron Microscopy of Fiber-Matrix Interfaces in Aluminum Alloy-Boron Composites by Ion Erosio

1971 ◽  
Vol 29 ◽  
pp. 204-205
Author(s):  
G. G. Shaw
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aluminum Alloy ◽  
Electron Beam ◽  
Pure Aluminum ◽  
Ion Milling ◽  
Transmission Electron ◽  
Fiber Matrix ◽  
Ion Erosion ◽  
Row Of Fibers

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.

Direct Observation of Heat Exchanger Deposits by Cross Sectioning

1967 ◽  
Vol 25 ◽  
pp. 364-365
Author(s):  
R. W. Anderson ◽  
D. L. Senecal
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heat Exchanger ◽  
Direct Observation ◽  
Cross Sections ◽  
Preparation Method ◽  
Specimen Preparation ◽  
Flowing Water ◽  
Transmission Electron ◽  
Deposit Layer

A problem was presented to observe the packing densities of deposits of sub-micron corrosion product particles. The deposits were 5-100 mils thick and had formed on the inside surfaces of 3/8 inch diameter Zircaloy-2 heat exchanger tubes. The particles were iron oxides deposited from flowing water and consequently were only weakly bonded. Particular care was required during handling to preserve the original formations of the deposits. The specimen preparation method described below allowed direct observation of cross sections of the deposit layers by transmission electron microscopy.The specimens were short sections of the tubes (about 3 inches long) that were carefully cut from the systems. The insides of the tube sections were first coated with a thin layer of a fluid epoxy resin by dipping. This coating served to impregnate the deposit layer as well as to protect the layer if subsequent handling were required.

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