scholarly journals A New Mechanism of the Selective Photodegradation of Antibiotics in the Catalytic System Containing TiO2 and the Inorganic Cations

2021 ◽  
Vol 22 (16) ◽  
pp. 8696
Author(s):  
Wojciech Baran ◽  
Mateusz Cholewiński ◽  
Andrzej Sobczak ◽  
Ewa Adamek
Keyword(s):  
Steric Effect ◽  
Inorganic Ions ◽  
High Sensitivity ◽  
Organic Radicals ◽  
Bond Polarity ◽  
Inorganic Cations ◽  
Tio2 Particles ◽  
Oxygen Conditions ◽  
High Bond ◽  
Electron Holes

The mechanism of sulfisoxazole (SFF) selective removal by photocatalysis in the presence of titanium (IV) oxide (TiO2) and iron (III) chloride (FeCl3) was explained and the kinetics and degradation pathways of SFF and other antibiotics were compared. The effects of selected inorganic ions, oxygen conditions, pH, sorption processes and formation of coordination compounds on the photocatalytic process in the presence of TiO2 were also determined. The Fe3+ compounds added to the irradiated sulfonamide (SN) solution underwent surface sorption on TiO2 particles and act as acceptors of excited electrons. Most likely, the SFF degradation is also intensified by organic radicals or cation organic radicals. These radicals can be initially generated by reaction with electron holes, hydroxyl radicals and as a result of electron transfer mediated by iron ions and then participate in propagation processes. The high sensitivity of SFF to decomposition caused by organic radicals is associated with the steric effect and the high bond polarity of the amide substituent.

scholarly journals Major Inorganic Ions in Bottled Waters from Several Polish and Romanian Mineral Waters

2019 ◽  
Vol 76 (1) ◽  
pp. 70
Author(s):  
Rajmund MICHALSKI ◽  
Joanna KOŃCZYK ◽  
Edward MUNTEAN ◽  
Jerzy GĘGA ◽  
Aleksandra FRYMUS
Keyword(s):  
Chemical Composition ◽  
Analytical Method ◽  
Microwave Plasma ◽  
Inorganic Ions ◽  
Atomic Emission ◽  
Mineral Waters ◽  
Atomic Emission Spectrometry ◽  
Good Knowledge ◽  
Emission Spectrometry ◽  
Inorganic Cations

Mineral waters are important sources of micro- and macroelements for humans, thus its composition ought to be supported with good knowledge on their chemical composition and be controlled systematically. The aim of the study was to analyze the content of common inorganic cations in 9 Romanian and 9 Polish bottled waters, and compare the results of the analyses with the product label’s data. The novelty was the application of new analytical method (atomic emission spectrometry with microwave plasma) for this approach. A short chemometric evaluation of the obtained results was carried out, highlighting in many cases significant differences between the values declared by the producers and the obtained results; possible reasons of this situation are discussed.

Applications of EPR Spectrometer in Environmental Samples

2015 ◽  
Vol 1092-1093 ◽  
pp. 589-592
Author(s):  
Shao Hua Liao ◽  
Fang Yang ◽  
Fang Fang Li ◽  
Jing Yang ◽  
Min Wu
Keyword(s):  
Carbon Nanotubes ◽  
Electron Paramagnetic Resonance ◽  
Free Radicals ◽  
Transition Metals ◽  
Environmental Samples ◽  
High Sensitivity ◽  
Organic Radicals ◽  
Paramagnetic Resonance ◽  
Potential Risks ◽  
Electron Paramagnetic

Electron paramagnetic resonance (EPR) spectrometer was widely applied to physics, chemistry and biomedicine. This research provided possible electron and valence information of environmental samples interaction through high sensitivity. The EPR signals of transition metals and organic radicals were distinguished well. Three kinds of carbon nanotubes (CNTs) (MW50, MW30 and MWG) had strong EPR signals. Addition of transition metals may be a suitable way to decrease environmentally persistent free radicals (EPFRs). The potential risks of EPFRs in BC and the reactive free electron in transition metals must be addressed to ensure their safe and scientific absorption application.

Three new luminescent Cd(ii)-MOFs by regulating the tetracarboxylate and auxiliary co-ligands, displaying high sensitivity for Fe3+ in aqueous solution

2015 ◽  
Vol 44 (22) ◽  
pp. 10385-10391 ◽  
Author(s):  
Yunlong Wu ◽  
Guo-Ping Yang ◽  
Xiang Zhou ◽  
Jiang Li ◽  
Yan Ning ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Steric Effect ◽  
High Sensitivity

Three new luminescent Cd(ii)-MOFs have been synthesized by regulating the steric effect of tetracarboxylate and auxiliary co-ligands. Notably, 3 displayed high sensitivity for Fe3+ in aqueous solution with mixed ions.

scholarly journals Adsorption of Organic Compounds on to Bentonites Modified with Single or Dual Quaternary Ammonium Cations

2003 ◽  
Vol 21 (2) ◽  
pp. 135-148 ◽  
Author(s):  
R. Gönülşen ◽  
N. Yıldız ◽  
A. Çalımlı
Keyword(s):  
Quaternary Ammonium ◽  
Cation Exchange Capacity ◽  
Competitive Adsorption ◽  
Inorganic Ions ◽  
Exchange Capacity ◽  
Mineral Surface ◽  
Adsorption Mechanisms ◽  
Inorganic Cations ◽  
Quaternary Ammonium Cations ◽  
Adsorption Affinity

The adsorption of benzoic acid, hydroquinone and toluene on to bentonites modified with single or dual quaternary ammonium cations was studied. Thus, the mineral surface of the bentonite was modified by replacing the inorganic ions with four quaternary ammonium cations, i.e. tetramethylammonium (TMA), benzyltriethylammonium (BTEA), hexadecyltrimethylammonium (HDTMA) and octadecyltrimethylammonium (ODTMA). The inorganic cations on the bentonite were exchanged with the quaternary ammonium cations to the respective extent of ca. 35% TMA, 75% BTEA, 83% HDTMA, 90% ODTMA, 35% TMA/54% HDTMA, 35% TMA/58% ODTMA and 75% BTEA/12% HDTMA of the cation-exchange capacity (CEC) of the bentonite, resulting in a change in the surface properties from hydrophilic to organophilic. The experimental results obtained indicated that the adsorption affinity on dual-modified bentonites was generally lower than that on single-modified bentonites. It was concluded that this resulted from two different adsorption mechanisms and the competitive adsorption of binary solutes.

Influence of Organic and Inorganic Ions on Organolead-Induced Hemolysis of Erythrocytes

2001 ◽  
Vol 56 (9-10) ◽  
pp. 853-856
Keyword(s):  
Protective Efficacy ◽  
Inorganic Ions ◽  
Organic C ◽  
Inorganic Cations ◽  
Rbc Membrane ◽  
Hemolytic Effect ◽  
Organolead Compounds

Abstract The influence of some inorganic (K+, Mg2+, and Al3+) and organic CnH2n+1SO3-, n=12 and 14) ions was studied on the hemolysis of erythrocytes (RBC) caused by organolead compounds (tripropyllead -TPL, tributyllead -TBL and triphenyllead -TPhL chlorides). It was found that sulfonate anions increased the hemolytic effect induced by triorganoleads, while inorganic cations protected RBC against the triorganoleads action, especially when the latter were used at small concentrations. This protection was weaker when the concentration of organoleads increased and depended on the kind of ion. The protective efficacy sequence was like that: Mg2+ > Al3+ > K+. The less hemolytic of the triorganoleads studied was TPL. TBL was slightly more effective than TPhL. The efficacy of the sulfonate ions to increase the triorganolead chloride -induced hemolysis was practically the same for TPL and TBL. A weaker efficacy of C12H25SO3+ was observed when TPhL was used as RBC membrane modifier.

Radio Measurements of Coronal Magnetic Fields

1994 ◽  
Vol 144 ◽  
pp. 21-28 ◽  
Author(s):  
G. B. Gelfreikh
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Solar Corona ◽  
Active Regions ◽  
High Sensitivity ◽  
Coronal Magnetic Field ◽  
Transverse Magnetic ◽  
Radio Sources ◽  
Radio Waves ◽  
Solar Active Regions

AbstractA review of methods of measuring magnetic fields in the solar corona using spectral-polarization observations at microwaves with high spatial resolution is presented. The methods are based on the theory of thermal bremsstrahlung, thermal cyclotron emission, propagation of radio waves in quasi-transverse magnetic field and Faraday rotation of the plane of polarization. The most explicit program of measurements of magnetic fields in the atmosphere of solar active regions has been carried out using radio observations performed on the large reflector radio telescope of the Russian Academy of Sciences — RATAN-600. This proved possible due to good wavelength coverage, multichannel spectrographs observations and high sensitivity to polarization of the instrument. Besides direct measurements of the strength of the magnetic fields in some cases the peculiar parameters of radio sources, such as very steep spectra and high brightness temperatures provide some information on a very complicated local structure of the coronal magnetic field. Of special interest are the results found from combined RATAN-600 and large antennas of aperture synthesis (VLA and WSRT), the latter giving more detailed information on twodimensional structure of radio sources. The bulk of the data obtained allows us to investigate themagnetospheresof the solar active regions as the space in the solar corona where the structures and physical processes are controlled both by the photospheric/underphotospheric currents and surrounding “quiet” corona.

Backscattered Electron Imaging of GaAs/AlGaAs Super Lattice Structures with an Ultra-High- Resolution SEM

1988 ◽  
Vol 46 ◽  
pp. 204-205
Author(s):  
Kazumichi Ogura ◽  
Michael M. Kersker
Keyword(s):  
High Resolution ◽  
Layer Structure ◽  
High Sensitivity ◽  
Beam Current ◽  
Electron Beam Current ◽  
Lattice Structures ◽  
Super Lattice ◽  
Different Types ◽  
Backscattered Electron ◽  
Electron Imaging

Backscattered electron (BE) images of GaAs/AlGaAs super lattice structures were observed with an ultra high resolution (UHR) SEM JSM-890 with an ultra high sensitivity BE detector. Three different types of super lattice structures of GaAs/AlGaAs were examined. Each GaAs/AlGaAs wafer was cleaved by a razor after it was heated for approximately 1 minute and its crosssectional plane was observed.First, a multi-layer structure of GaAs (100nm)/AlGaAs (lOOnm) where A1 content was successively changed from 0.4 to 0.03 was observed. Figures 1 (a) and (b) are BE images taken at an accelerating voltage of 15kV with an electron beam current of 20pA. Figure 1 (c) is a sketch of this multi-layer structure corresponding to the BE images. The various layers are clearly observed. The differences in A1 content between A1 0.35 Ga 0.65 As, A1 0.4 Ga 0.6 As, and A1 0.31 Ga 0.69 As were clearly observed in the contrast of the BE image.

An x-ray microprobe based upon a close-coupled focal-spot / glass capillary arrangement

1992 ◽  
Vol 50 (2) ◽  
pp. 1758-1759
Author(s):  
D. A. Carpenter ◽  
M. A. Taylor
Keyword(s):  
Imaging Techniques ◽  
Fluorescence Analysis ◽  
High Sensitivity ◽  
Specimen Preparation ◽  
X Rays ◽  
Glass Capillary ◽  
Close Coupling ◽  
X Ray ◽  
Point To Point ◽  
Beam Damage

The development of intense sources of x rays has led to renewed interest in the use of microbeams of x rays in x-ray fluorescence analysis. Sparks pointed out that the use of x rays as a probe offered the advantages of high sensitivity, low detection limits, low beam damage, and large penetration depths with minimal specimen preparation or perturbation. In addition, the option of air operation provided special advantages for examination of hydrated systems or for nondestructive microanalysis of large specimens.The disadvantages of synchrotron sources prompted the development of laboratory-based instrumentation with various schemes to maximize the beam flux while maintaining small point-to-point resolution. Nichols and Ryon developed a microprobe using a rotating anode source and a modified microdiffractometer. Cross and Wherry showed that by close-coupling the x-ray source, specimen, and detector, good intensities could be obtained for beam sizes between 30 and 100μm. More importantly, both groups combined specimen scanning with modern imaging techniques for rapid element mapping.

Ultrastructural identification of three types of sensory setae on copepod antennae

1995 ◽  
Vol 53 ◽  
pp. 956-957
Author(s):  
T. M. Weatherby ◽  
P.H. Lenz
Keyword(s):  
Phase Locking ◽  
Membrane Surface ◽  
Reaction Times ◽  
High Sensitivity ◽  
Structural Features ◽  
Calanoid Copepods ◽  
Marine Food Webs ◽  
Dendritic Membrane ◽  
Ultrastructural Characterization

Crustaceans, as well as other arthropods, are covered with sensory setae and hairs, including mechanoand chemosensory sensillae with a ciliary origin. Calanoid copepods are small planktonic crustaceans forming a major link in marine food webs. In conjunction with behavioral and physiological studies of the antennae of calanoids, we undertook the ultrastructural characterization of sensory setae on the antennae of Pleuromamma xiphias.Distal mechanoreceptive setae exhibit exceptional behavioral and physiological performance characteristics: high sensitivity (<10 nm displacements), fast reaction times (<1 msec latency) and phase locking to high frequencies (1-2 kHz). Unusual structural features of the mechanoreceptors are likely to be related to their physiological sensitivity. These features include a large number (up to 3000) of microtubules in each sensory cell dendrite, arising from or anchored to electron dense rods associated with the ciliary basal body microtubule doublets. The microtubules are arranged in a regular array, with bridges between and within rows. These bundles of microtubules extend far into each mechanoreceptive seta and terminate in a staggered fashion along the dendritic membrane, contacting a large membrane surface area and providing a large potential site of mechanotransduction.

Slow-Scan CCD Observation of Backscattering Patterns in SEM

1992 ◽  
Vol 50 (2) ◽  
pp. 1308-1309
Author(s):  
F. Ouyang ◽  
D. A. Ray ◽  
O. L. Krivanek
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Dynamic Range ◽  
High Sensitivity ◽  
Lens System ◽  
Wide Dynamic Range ◽  
Peltier Cooler ◽  
Diffraction Patterns ◽  
Scanning Electron

Electron backscattering Kikuchi diffraction patterns (BKDP) reveal useful information about the structure and orientation of crystals under study. With the well focused electron beam in a scanning electron microscope (SEM), one can use BKDP as a microanalysis tool. BKDPs have been recorded in SEMs using a phosphor screen coupled to an intensified TV camera through a lens system, and by photographic negatives. With the development of fiber-optically coupled slow scan CCD (SSC) cameras for electron beam imaging, one can take advantage of their high sensitivity and wide dynamic range for observing BKDP in SEM.We have used the Gatan 690 SSC camera to observe backscattering patterns in a JEOL JSM-840A SEM. The CCD sensor has an active area of 13.25 mm × 8.83 mm and 576 × 384 pixels. The camera head, which consists of a single crystal YAG scintillator fiber optically coupled to the CCD chip, is located inside the SEM specimen chamber. The whole camera head is cooled to about -30°C by a Peltier cooler, which permits long integration times (up to 100 seconds).

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