scholarly journals Innovative Characterization of Particulate Matter Deposited on Urban Vegetation Leaves through the Application of a Chemical Fractionation Procedure

2020 ◽  
Vol 17 (16) ◽  
pp. 5717
Author(s):  
Martina Ristorini ◽  
Chiara Baldacchini ◽  
Lorenzo Massimi ◽  
Gregorio Sgrigna ◽  
Carlo Calfapietra
Keyword(s):  
Particulate Matter ◽  
Insoluble Fraction ◽  
Ionic Concentration ◽  
Water Soluble ◽  
Chemical Fractionation ◽  
X Rays ◽  
Membrane Filters ◽  
Fractionation Procedure ◽  
Specific Source

In this study, we have evaluated the efficiency of a chemical fractionation procedure for the characterization of both the water-soluble and the insoluble fraction of the main elemental components of particulate matter (PM) deposited on urban leaves. The proposed analytical approach is based on the chemical analysis of leaf washing solutions and membrane filters used for their filtration. The ionic concentration of leaf washing solutions was compared with their electrical conductivity, making it a valuable proxy for the quantification of the water-soluble and ionic fraction of leaf deposited PM. The chemical composition of both the water-soluble and the insoluble fraction of PM, resulting from this fractionation procedure, was compared with results obtained by scanning electron microscopy coupled with energy-dispersed X-Rays spectroscopy (SEM/EDX) and processed through chemometrics. Results obtained proved that the proposed approach is able to provide an estimation of total leaf deposited PM and it is highly reliable for the evaluation of the emission impact of different PM sources, being able to increase the selectivity of PM elemental components as specific source tracers; consequently providing useful information also for the assessment of human health risks.

scholarly journals Characterization of Urban Particulate Matter by Diffusive Gradients in Thin Film Technique

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Michaela Dufka ◽  
Bohumil Dočekal
Keyword(s):  
Particulate Matter ◽  
Inductively Coupled Plasma ◽  
Heavy Traffic ◽  
Total Content ◽  
Insoluble Fraction ◽  
Inductively Coupled ◽  
Significant Difference ◽  
Thickness Of Diffusion Layer ◽  
Plasma Mass Spectrometry

A diffusive gradient in thin films (DGT) technique was employed in characterization of the particulate matter related to the urban area suffering from heavy traffic. Kinetics of mobilization metals fluxes from the metal-contaminated particulate matter was investigated. To monitor responses of the particulate matter sample, DGT probes of various thickness of diffusion layer were deployed in aqueous model suspensions of the particulate matter for different time periods. Particulate matter samples and exposed DGT resin gels were decomposed in a mixture of nitric and hydrochloric acid in a microwave pressurized PTFE-lined system. Total content of some traffic-related elements (Cd, Co, Cu, Mo, Ni, Pb, Pd, Pt, Rh, Sb, and V) was determined by inductively coupled plasma mass spectrometry. DGT measurements revealed that two metals pools associated with particles could be recognized, which can be characterized as high soluble fraction and almost insoluble fraction. DGT-measured metal fluxes from the labile pool showed significant difference in mobilization and resupply fluxes of individual selected elements, which might reflect the origin of selected metals and their speciation in particulate matter. The DGT technique can be applied as a useful tool for characterization of metals mobilization from the particulate matter.

Digital x-ray mapping of nanometer-size supported bimetallic catalysts

1988 ◽  
Vol 46 ◽  
pp. 530-531
Author(s):  
L. T. Germinario
Keyword(s):  
Background Radiation ◽  
Metal Cluster ◽  
Single Element ◽  
Beam Diameter ◽  
X Rays ◽  
X Ray ◽  
Major Interest ◽  
Induced Changes

Understanding the role of metal cluster composition in determining catalytic selectivity and activity is of major interest in heterogeneous catalysis. The electron microscope is well established as a powerful tool for ultrastructural and compositional characterization of support and catalyst. Because the spatial resolution of x-ray microanalysis is defined by the smallest beam diameter into which the required number of electrons can be focused, the dedicated STEM with FEG is the instrument of choice. The main sources of errors in energy dispersive x-ray analysis (EDS) are: (1) beam-induced changes in specimen composition, (2) specimen drift, (3) instrumental factors which produce background radiation, and (4) basic statistical limitations which result in the detection of a finite number of x-ray photons. Digital beam techniques have been described for supported single-element metal clusters with spatial resolutions of about 10 nm. However, the detection of spurious characteristic x-rays away from catalyst particles produced images requiring several image processing steps.

Characterization of Rh/Si multilayer structure by HREM and HAADF

1992 ◽  
Vol 50 (1) ◽  
pp. 122-123
Author(s):  
Y. Cheng ◽  
J. Liu ◽  
M.B. Stearns ◽  
D.G. Steams
Keyword(s):  
Normal Incidence ◽  
High Resolution Electron Microscopy ◽  
X Rays ◽  
Beam Direction ◽  
Cross Sectional ◽  
Optical Elements ◽  
Resolution Electron ◽  
Point To Point ◽  
Better Than

The Rh/Si multilayer (ML) thin films are promising optical elements for soft x-rays since they have a calculated normal incidence reflectivity of ∼60% at a x-ray wavelength of ∼13 nm. However, a reflectivity of only 28% has been attained to date for ML fabricated by dc magnetron sputtering. In order to determine the cause of this degraded reflectivity the microstructure of this ML was examined on cross-sectional specimens with two high-resolution electron microscopy (HREM and HAADF) techniques.Cross-sectional specimens were made from an as-prepared ML sample and from the same ML annealed at 298 °C for 1 and 100 hours. The specimens were imaged using a JEM-4000EX TEM operating at 400 kV with a point-to-point resolution of better than 0.17 nm. The specimens were viewed along Si [110] projection of the substrate, with the (001) Si surface plane parallel to the beam direction.

Characterization of Chemical Impurities in Glutaraldehyde

1975 ◽  
Vol 33 ◽  
pp. 620-621
Author(s):  
B. J. Grenon ◽  
A. J. Tousimis
Keyword(s):  
Glutaric Acid ◽  
Spectroscopic Analysis ◽  
Aldol Condensation ◽  
Condensation Product ◽  
Amorphous Solid ◽  
Water Soluble ◽  
Impurity Component ◽  
Chemical Impurities ◽  
Soluble Liquid

Ever since the introduction of glutaraldehyde as a fixative in electron microscopy of biological specimens, the identification of impurities and consequently their effects on biologic ultrastructure have been under investigation. Several reports postulate that the impurities of glutaraldehyde, used as a fixative, are glutaric acid, glutaraldehyde polymer, acrolein and glutaraldoxime.Analysis of commercially available biological or technical grade glutaraldehyde revealed two major impurity components, none of which has been reported. The first compound is a colorless, water-soluble liquid with a boiling point of 42°C at 16 mm. Utilizing Nuclear Magnetic Resonance (NMR) spectroscopic analysis, this compound has been identified to be — dihydro-2-ethoxy 2H-pyran. This impurity component of the glutaraldehyde biological or technical grades has an UV absorption peak at 235nm. The second compound is a white amorphous solid which is insoluble in water and has a melting point of 80-82°C. Initial chemical analysis indicates that this compound is an aldol condensation product(s) of glutaraldehyde.

Incorporation of micro/nanoparticles of PCL with essential oil of Cymbopogon nardus in bacterial cellulose

2018 ◽  
Vol 1 (2) ◽  
pp. 37
Author(s):  
Aline Krindges ◽  
Vanusca Dalosto Jahno ◽  
Fernando Morisso
Keyword(s):  
Particle Size ◽  
Particulate Matter ◽  
Essential Oil ◽  
Zeta Potential ◽  
Bacterial Cellulose ◽  
Culture Medium ◽  
Static Culture ◽  
Cymbopogon Nardus ◽  
Cellulose Membranes

Incorporation studies of particles in different substrates with herbal assets growing. The objective of this work was the preparation and characterization of micro/nanoparticles containing cymbopogon nardus essential oil; and the incorporation of them on bacterial cellulose. For the development of the membranes was used the static culture medium and for the preparation of micro/nanoparticles was used the nanoprecipitation methodology. The incorporation of micro/nanoparticles was performed on samples of bacterial cellulose in wet and dry form. For the characterization of micro/nanoparticles were carried out analysis of SEM, zeta potential and particle size. For the verification of the incorporation of particulate matter in cellulose, analyses were conducted of SEM and FTIR. The results showed that it is possible the production and incorporation of micro/nanoparticles containing essential oil in bacterial cellulose membranes in wet form with ethanol.

Characterization of particulate matter 2.5 in an urban tertiary care hospital in the Philippines

2015 ◽  
Vol 92 ◽  
pp. 432-439 ◽  
Author(s):  
Marian Fe Theresa C. Lomboy ◽  
Leni L. Quirit ◽  
Victorio B. Molina ◽  
Godofreda V. Dalmacion ◽  
Joel D. Schwartz ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Tertiary Care Hospital ◽  
Tertiary Care ◽  
The Philippines ◽  
Care Hospital ◽  
Particulate Matter 2.5
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