scholarly journals Re-recognizing micro locations of nanoscale zero-valent iron in biochar using C-TEM technique

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kun Yang ◽  
Jialu Xu ◽  
Ming Zhang ◽  
Daohui Lin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Zero Valent Iron ◽  
Iron Hydroxides ◽  
Cross Sectional ◽  
Reducing Ability ◽  
Transmission Electron ◽  
Nanoscale Zero Valent Iron ◽  
Scanning Electron

AbstractBiochar supported nanoscale zero-valent iron (NZVI/BC), prepared commonly by liquid reduction using sodium borohydride (NaBH4), exhibits better reduction performance for contaminants than bare NZVI. The better reducing ability was attributed to attachment of nanoscale zero-valent iron (NZVI) on biochar (BC) surface or into the interior pores of BC particles due to observations by scanning electron microscopy (SEM) and plan transmission electron microscopy (P-TEM) techniques in previous studies. In this study, cross-sectional TEM (C-TEM) technique was employed firstly to explore location of NZVI in NZVI/BC. It was observed that NZVI is isolated from BC particles, but not located on the surface or in the interior pores of BC particles. This observation was also supported by negligible adsorption and precipitation of Fe2+/Fe3+ and iron hydroxides on BC surface or into interior pores of BC particles respectively. Precipitation of Fe2+ and Fe3+, rather than adsorption, is responsible for the removal of Fe2+ and Fe3+ by BC. Moreover, precipitates of iron hydroxides cannot be reduced to NZVI by NaBH4. In addition to SEM or P-TEM, therefore, C-TEM is a potential technique to characterize the interior morphology of NZVI/BC for better understanding the improved reduction performance of contaminants by NZVI/BC than bare NZVI.

scholarly journals Re-recognizing Micro Locations of Nanoscale Zero-valent Iron in Biochar Using C-TEM technique

2020 ◽  
Author(s):  
Kun Yang ◽  
Jialu Xu ◽  
Ming Zhang ◽  
Daohui Lin
Keyword(s):  
Electron Microscopy ◽  
Zero Valent Iron ◽  
Iron Hydroxides ◽  
Cross Sectional ◽  
Reducing Ability ◽  
Transmission Electron ◽  
Reduction Mechanisms ◽  
Nanoscale Zero Valent Iron ◽  
And Performance ◽  
Scanning Electron

Abstract Biochar supported nanoscale zero-valent iron (NZVI/BC), prepared commonly by liquid reduction using sodium borohydride (NaBH4), exhibits better reduction performance for contaminants than bulk NZVI. The better reducing ability was attributed to attachment of nanoscale zero-valent iron (NZVI) on biochar (BC) surface or into interior pores of BC particles due to observations by scanning electron microscopy (SEM) and plan transmission electron microscopy (P-TEM) techniques in previous studies. In this study, cross-sectional TEM (C-TEM) technique was employed firstly to explore location of NZVI in NZVI/BC. It was observed that NZVI is isolated from BC particles, but not located on the surface or in the interior pores of BC particles. This observation was also supported by negligible adsorption and precipitation of Fe2+/Fe3+ and iron hydroxides on BC surface or into interior pores of BC particles respectively. Precipitation of Fe2+ and Fe3+, rather than adsorption, is responsible for the removal of Fe2+ and Fe3+ by BC. Moreover, precipitates of iron hydroxides cannot be reduced to NZVI by NaBH4. In addition to SEM or P-TEM, therefore, C-TEM is a potential technique which should be employed to characterize the interior morphology of NZVI/BC for better understanding the reduction mechanisms and performance of contaminants by NZVI/BC.

The Formation Mechanism of Carrot Defects in SiC Epifilms

2006 ◽  
Vol 911 ◽  
Author(s):  
Hui Chen ◽  
Guan Wang ◽  
Yi Chen ◽  
Xiaoting Jia ◽  
Jie Bai ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Mechanism Of Formation ◽  
Cross Sectional ◽  
Screw Dislocations ◽  
X Ray ◽  
Transmission Electron ◽  
Sic Wafer ◽  
Scanning Electron

AbstractCarrot-like defects in a 7&#61616; off-cut (from [0001] toward <1-210> direction) 4H-SiC wafer with a 36μm thick 4H-SiC epilayer have been investigated using Nomarski optical microscopy, synchrotron white beam x-ray topography (SWBXT), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). X-ray topographs confirm that threading screw dislocations are often associated with the carrots. Cross-sectional TEM observation confirms that a prismatic stacking fault exists below the carrot. This fault was found to show contrast in all observed diffraction geometries except for g=0004. A model for the mechanism of formation of this type of defect during epitaxial growth is proposed.

Dislocation-Related Etch Protrusions Formed on 4H-SiC (000-1) Surfaces by Molten KOH Etching

2006 ◽  
Vol 911 ◽  
Author(s):  
Masahide Gotoh ◽  
Takeshi Tawara ◽  
Shun-ichi Nakamura ◽  
Tae Tamori ◽  
Yoshiyuki Kuboki ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cross Sectional ◽  
Surface Features ◽  
Transmission Electron ◽  
Koh Etching ◽  
Scanning Electron

AbstractIn this study, we investigated surface features formed by molten KOH etching of (000-1) substrates and epilayers, using scanning electron microscopy (SEM) and cross-sectional transmission electron microscopy (TEM). We found the surface features formed on (000-1) are protrusions, in contrast to well-known dimples on (0001).

Two- or three-way observations of the identical cell elements within the same sections by LM, TEM and/or SEM

1978 ◽  
Vol 36 (2) ◽  
pp. 82-83 ◽  
Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Light Microscopy ◽  
Thin Sections ◽  
Transmission Electron ◽  
Identical Cell ◽  
Electron Microscopes ◽  
Scanning Electron

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).

Comparative Study of the Fine Morphology of Sensory Receptors in Aspidogaster conchicola and Cotylaspis insignis

1972 ◽  
Vol 30 ◽  
pp. 150-151
Author(s):  
Venita F. Allison ◽  
J. E. Ubelaker ◽  
J. H. Martin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Nervous System ◽  
Osmic Acid ◽  
Sensory Receptors ◽  
Transmission Electron ◽  
Sensory Structures ◽  
Fine Morphology ◽  
Scanning Electron

It has been suggested that parasitism results in a reduction of sensory structures which concomitantly reflects a reduction in the complexity of the nervous system. The present study tests this hypothesis by examining the fine morphology and the distribution of sensory receptors for two species of aspidogastrid trematodes by transmission and scanning electron microscopy. The species chosen are an ectoparasite, Cotylaspis insignis and an endoparasite, Aspidogaster conchicola.Aspidogaster conchicola and Cotylaspis insignis were obtained from natural infections of clams, Anodonta corpulenta and Proptera purpurata. The specimens were fixed for transmission electron microscopy in phosphate buffered paraformaldehyde followed by osmic acid in the same buffer, dehydrated in an ascending series of ethanol solutions and embedded in Epon 812.

Anisotropic Membranes as Substrates for Sem

1976 ◽  
Vol 34 ◽  
pp. 444-445
Author(s):  
Thomas P. Turnbull ◽  
W. F. Bowers
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Flow ◽  
Polymer Chemistry ◽  
Surface Porosity ◽  
Transmission Electron ◽  
Pore Texture ◽  
Spongy Layer ◽  
Scanning Electron

Until recently the prime purposes of filters have been to produce clear filtrates or to collect particles from solution and then remove the filter medium and examine the particles by transmission electron microscopy. These filters have not had the best characteristics for scanning electron microscopy due to the size of the pores or the surface topography. Advances in polymer chemistry and membrane technology resulted in membranes whose characteristics make them versatile substrates for many scanning electron microscope applications. These polysulphone type membranes are anisotropic, consisting of a very thin (0.1 to 1.5 μm) dense skin of extremely fine, controlled pore texture upon a much thicker (50 to 250μm), spongy layer of the same polymer. Apparent pore diameters can be controlled in the range of 10 to 40 A. The high flow ultrafilters which we are describing have a surface porosity in the range of 15 to 25 angstrom units (0.0015-0.0025μm).

Digital imaging: When should one take the plunge?

1996 ◽  
Vol 54 ◽  
pp. 602-603
Author(s):  
John F. Mansfield
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Optical Microscopy ◽  
Digital Imaging ◽  
Storage Devices ◽  
Major Benefit ◽  
Transmission Electron ◽  
New Instrument ◽  
Scanning Electron

The current imaging trend in optical microscopy, scanning electron microscopy (SEM) or transmission electron microscopy (TEM) is to record all data digitally. Most manufacturers currently market digital acquisition systems with their microscope packages. The advantages of digital acquisition include: almost instant viewing of the data as a high-quaity positive image (a major benefit when compared to TEM images recorded onto film, where one must wait until after the microscope session to develop the images); the ability to readily quantify features in the images and measure intensities; and extremely compact storage (removable 5.25” storage devices which now can hold up to several gigabytes of data).The problem for many researchers, however, is that they have perfectly serviceable microscopes that they routinely use that have no digital imaging capabilities with little hope of purchasing a new instrument.

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