scholarly journals Chemical characterization of laboratory-generated tar ball particles

2018 ◽  
Author(s):  
Ádám Tóth ◽  
András Hoffer ◽  
Mihály Pósfai ◽  
Tibor Ajtai ◽  
Zoltán Kónya ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Chemical Characterization ◽  
Analytical Techniques ◽  
Total Carbon ◽  
Total Carbon Content ◽  
Molar Ratios ◽  
Carbon Structures ◽  
Sampling Campaign ◽  
Ft Ir ◽  
Heterocyclic Aromatics

Abstract. The chemical properties of tar ball (TB) particles generated from dry distillate (wood tars) of three different wood species in the laboratory were investigated by analytical techniques that had never been used before, for their characterization. The elemental composition of TB particles from three tree species were very similar to one another and to those characteristic for atmospheric tar balls (TBs) collected from savanna fire during the SAFARI 2000 sampling campaign. The O / C and H / C molar ratios of the generated TBs were at the upper limit characteristic for soot particles. The FT-IR spectra of the generated TBs were very similar to one another as well and also showed some similarity with those of atmospheric humic-like substances (HULIS). The FT-IR measurements indicated that laboratory-generated TBs have a higher proportion of aromatic structure than HULIS and the oxygen atoms of TBs are mainly found in hydroxyl and keto functional groups. Whereas the starting materials of the TBs (wood tars) were Raman inactive in the range of 1000–1800 cm−1, the Raman spectra of TBs were dominated by two pronounced bands with intensity maxima near 1580 (G band) and 1350 cm−1 (D band), indicating the presence of sp2-hybridised carbon structures and disorder in them, respectively. In the Py-GC-MS chromatograms of the laboratory-generated TBs mostly aromatic compounds (aromatic hydrocarbons, oxygenated aromatics and heterocyclic aromatics) were identified in accordance with the results of Raman and FT-IR spectroscopy. According to OC / EC analysis using EUSAAR_2 long thermal protocol, 22 % of the total carbon content of laboratory-generated TBs was identified as elemental carbon (EC), contrary to expectations based on the current understanding that negligible if any EC is present in this sub-fraction of the brown carbon family. Our results suggest that spherical atmospheric TBs with high C / O molar ratios are closer to BC in many of their properties than to weakly absorbing HULIS.

scholarly journals Chemical characterization of laboratory-generated tar ball particles

2018 ◽  
Vol 18 (14) ◽  
pp. 10407-10418 ◽  
Author(s):  
Ádám Tóth ◽  
András Hoffer ◽  
Mihály Pósfai ◽  
Tibor Ajtai ◽  
Zoltán Kónya ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Chemical Characterization ◽  
Analytical Techniques ◽  
Total Carbon ◽  
Total Carbon Content ◽  
Molar Ratios ◽  
Sampling Campaign ◽  
Tar Balls ◽  
Ft Ir ◽  
Heterocyclic Aromatics

Abstract. The chemical properties of laboratory-generated tar ball (Lab-TB) particles produced from dry distillate (wood tars) of three different wood species in the laboratory were investigated by analytical techniques that had never been used before for their characterization. The elemental compositions of laboratory-generated tar balls (Lab-TBs) from three tree species were very similar to one another and to those characteristic of atmospheric tar balls (TBs) collected from the savanna fire during the SAFARI 2000 sampling campaign. The O ∕ C and H ∕ C molar ratios of the generated Lab-TBs were at the upper limit characteristic of soot particles. The Fourier transform infrared spectroscopy (FT-IR) spectra of the generated Lab-TBs were very similar to one another as well and also showed some similarity with those of atmospheric humic-like substances (HULIS). The FT-IR measurements indicated that Lab-TBs have a higher proportion of aromatic structure than HULIS and the oxygen atoms of Lab-TBs are mainly found in hydroxyl and keto functional groups. Whereas Raman activity was detected in the starting materials of the Lab-TBs (wood tars) in the range of 1000–1800 cm−1, the Raman spectra of TBs were dominated by two pronounced bands with intensity maxima near 1580 (G band) and 1350 cm−1 (D band), indicating the presence of sp2-hybridized carbon structures and disorder in them, respectively. In the Py-GC-MS chromatograms of the Lab-TBs mostly aromatic compounds (aromatic hydrocarbons, oxygenated aromatics and heterocyclic aromatics) were identified in accordance with the results of Raman and FT-IR spectroscopy. According to organic carbon ∕ elemental carbon (OC ∕ EC) analysis using EUSAAR_2 thermal protocol, 22 % of the total carbon content of Lab-TBs was identified as EC, contrary to expectations based on the current understanding that negligible if any EC is present in this sub-fraction of the brown carbon family. Our results suggest that spherical atmospheric TBs with high C ∕ O molar ratios are closer to BC in many of their properties than to weakly absorbing HULIS.

scholarly journals Comparison among Different Rewetting Strategies of Degraded Agricultural Peaty Soils: Short-Term Effects on Chemical Properties and Ecoenzymatic Activities

Agronomy ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1084
Author(s):  
Vittoria Giannini ◽  
Eleonora Peruzzi ◽  
Grazia Masciandaro ◽  
Serena Doni ◽  
Cristina Macci ◽  
...  
Keyword(s):  
Peat Soil ◽  
Management Strategies ◽  
Chemical Properties ◽  
Total Carbon ◽  
Available Phosphorus ◽  
Total Carbon Content ◽  
Peatland Restoration ◽  
Physico Chemical ◽  
Wetland System ◽  
Set Up

In 2013, a pilot experimental field of about 15 ha was set up within the basin of Lake Massaciuccoli (Tuscany, Italy) in order to compare different management strategies—a paludicultural system (PCS), a constructed wetland system (CWS), a nearly-natural wetland system (NWS)—for peatland restoration after almost a century of drainage-based agricultural use (CS). After five years, changes in peat soil quality were investigated from a chemical, biochemical, and ecoenzymatic perspective. The soil in CS was mainly characterized by oxidant conditions, higher content of overall microbial activity, low levels of easily available phosphorus for vegetation, and medium total carbon content ranging from 25.0% to 30.7%. In PCS, the levels of total carbon and the content of bioavailable P were higher, while the oxidant conditions were lower compared to the other systems. As expected, the soils in CWS and NWS were characterized by the most reduced conditions and by the highest levels of arylsulphatase activity. It was noteworthy that soils in the NWS systems were characterized by the highest level of nonavailable P. Outputs from ecoenzymatic activity confirmed the physico-chemical and biochemical results.

Analysis of Teos Silicon Dioxide: The Identification of Carbonatious Contaminants

1997 ◽  
Vol 500 ◽  
Author(s):  
M. L. Pereira Da Silva ◽  
A. Romanelli Cardoso ◽  
J. J. Santiago-Aviles
Keyword(s):  
Surface Characterization ◽  
Chemical Properties ◽  
Total Carbon ◽  
Electrical Characteristics ◽  
Total Carbon Content ◽  
Raman Scattering Spectroscopy ◽  
Physico Chemical ◽  
Organometallic Precursors ◽  
Deposited Films

ABSTRACTThis work presents the analysis performed on a SiO2 film deposited from organometallic precursors with the aim of correlating their physico-chemical properties including electrical characteristics with processing variables. The characterization tools used in this study included SEM for film homogeneity; SIMS for the determination of total carbon content; FT-MS and Raman scattering spectroscopy for surface characterization. GC-MS was used to understand the electrochemical reactions taking place while performing I-V characteristics measurements.The use of these multiple characterization techniques pointed out to deposited films with reasonable deposition characteristics but poor electrical ones. Phase segregated heterogeneity's rich in carbonatious residues influenced the degradation of the electrical characteristics.

scholarly journals The Physico-Chemical Properties of Glipizide: New Findings

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3142
Author(s):  
Giovanna Bruni ◽  
Ines Ghione ◽  
Vittorio Berbenni ◽  
Andrea Cardini ◽  
Doretta Capsoni ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Analytical Techniques ◽  
Kinetic Studies ◽  
Polymorphic Form ◽  
Decomposition Process ◽  
Endothermic Peak ◽  
Physico Chemical ◽  
New Findings ◽  
Chemical Studies ◽  
Ft Ir

The present work is a concrete example of how physico-chemical studies, if performed in depth, are crucial to understand the behavior of pharmaceutical solids and constitute a solid basis for the control of the reproducibility of the industrial batches. In particular, a deep study of the thermal behavior of glipizide, a hypoglycemic drug, was carried out with the aim of clarifying whether the recognition of its polymorphic forms can really be done on the basis of the endothermic peak that the literature studies attribute to the melting of the compound. A number of analytical techniques were used: thermal techniques (DSC, TGA), X-ray powder diffraction (XRPD), FT-IR spectroscopy and scanning electron microscopy (SEM). Great attention was paid to the experimental design and to the interpretation of the combined results obtained by all these techniques. We proved that the attribution of the endothermic peak shown by glipizide to its melting was actually wrong. The DSC peak is no doubt triggered by a decomposition process that involves gas evolution (cyclohexanamine and carbon dioxide) and formation of 5-methyl-N-[2-(4-sulphamoylphenyl) ethyl] pyrazine-2-carboxamide, which remains as decomposition residue. Thermal treatments properly designed and the combined use of DSC with FT-IR and XRPD led to identifying a new polymorphic form of 5-methyl-N-[2-(4-sulphamoylphenyl) ethyl] pyrazine-2-carboxamide, which is obtained by crystallization from the melt. Hence, our results put into evidence that the check of the polymorphic form of glipizide cannot be based on the temperature values of the DSC peak, since such a peak is due to a decomposition process whose Tonset value is strongly affected by the particle size. Kinetic studies of the decomposition process show the high stability of solid glipizide at room temperature.

scholarly journals In-situ physical and chemical characterization of the Eyjafjallajökull aerosol plume in the free troposphere over Italy

2013 ◽  
Vol 13 (8) ◽  
pp. 20195-20238
Author(s):  
S. Sandrini ◽  
L. Giulianelli ◽  
S. Decesari ◽  
M. C. Facchini ◽  
S. Fuzzi ◽  
...  
Keyword(s):  
Fine Fraction ◽  
Chemical Properties ◽  
Chemical Characterization ◽  
Analytical Techniques ◽  
Ground Level ◽  
Coarse Fraction ◽  
Volcanic Plume ◽  
Physical And Chemical ◽  
Aerosol Plume

Abstract. Continuous measurements of physical and chemical properties at the Mt. Cimone GAW-WMO Global Station (2165 m a.s.l.) allowed the detection of the volcanic aerosol plume resulting from the Eyjafjallajökull eruption of spring 2010. The event affected the site after a transport over a distance of more than 3000 km. Two main transport episodes were detected during the eruption period, showing a volcanic fingerprint discernible against the free tropospheric background conditions typical of the site, the first from 19 to 21 April and the second from 18 to 20 May 2010. The paper reports the modification of aerosol characteristics observed during the two episodes, both characterized by an abrupt increase in fine and, especially, coarse mode particle number. Analysis of major, minor and trace elements by different analytical techniques (Ionic Chromatography, PIXE-PIGE and ICP-MS) were performed on aerosols collected by ground level discrete sampling. The resulting database allows the characterization of aerosol chemical composition during the volcanic plume transport and in background conditions. During the passage of the volcanic plume, the fine fraction was dominated by sulphates, denoting the secondary origin of this mode, mainly resulting from in-plume oxidation of volcanic SO2. By contrast, the coarse fraction was characterized by increased concentration of numerous elements of crustal origin, such as Fe, Ti, Mn, Ca, Na, and Mg, which enter the composition of silicate minerals. Data analysis of selected elements (Ti, Al, Fe, Mn) allowed the estimation of the volcanic plume's contribution to total PM10, resulting in a local enhancement of up to 9.5 μg m-3, i.e. 40% of total PM10, on 18 May, which was the most intense of the two episodes. These results appear significant, especially in the light of the huge distance of Mt. Cimone from the source, confirming the widespread diffusion of the Eyjafjallajokull ashes over Europe.

scholarly journals Basic soil properties as a factor controlling the occurrence and intensity of water repellency in rankers of the White Carpathians

2015 ◽  
Vol 57 (3) ◽  
pp. 129-137
Author(s):  
Lucia Kořenková ◽  
Martin Urík
Keyword(s):  
Soil Properties ◽  
Water Drop ◽  
Negative Relationship ◽  
Chemical Properties ◽  
Water Repellency ◽  
Total Carbon ◽  
Soil Reaction ◽  
Arable Soils ◽  
Total Carbon Content ◽  
White Carpathians

Abstract Water repellency in soils is controlled by many different factors, basic physical and chemical properties might be considered the crucial ones. For the purpose of this study, 12 sites were selected and sampled (0–20 cm depth) in the White Carpathians. Repellency tests were conducted under laboratory conditions in triplicate using water drop penetration time (WDPT) test and the molarity of ethanol droplet (MED) test. Results of WDPT measurements showed that three samples were marked by slight to extreme water repellency. Regarding the relationship between WDPT/MED and tested soil properties, the highest value of correlation coefficient was calculated for soil organic carbon (r = 0.706; p < 0.05), suggesting there is a positive, statistically significant correlation between repellency severity and total carbon content. A negative relationship between repellency and soil reaction/silt/silt + clay contents of studied soils was found. Samples taken from the surface horizon of arable soils showed no repellency.

scholarly journals Dynamics of Changes in Selected Soil Traits in the Profiles of Arable Soils Anthropogenically Alkalised by the Cement and Lime Industry within the Kielecko-Łagowski Vale (Poland)

Land ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 84
Author(s):  
Anna Świercz ◽  
Agnieszka Gandzel ◽  
Ilona Tomczyk-Wydrych
Keyword(s):  
Dust Emission ◽  
Chemical Properties ◽  
Total Carbon ◽  
Arable Soils ◽  
Total Carbon Content ◽  
Caco3 Content ◽  
Study Results ◽  
Carbon And Nitrogen Content ◽  
Physical And Chemical ◽  
Alkaline Cations

This study presents the influence of the cement and lime industry on the physical and chemical properties of arable soils. In spite of using modern forms of environmental protection against dust emissions, this type of industry causes unfavourable phenomenon of excessive alkalisation of soil. This process is relatively rare in Poland. However, in the Świętokrzyskie Province, it has been responsible for the largest transformation of soils in recent years. The analysis included soil samples taken from five profiles located in the vicinity of Dyckerhoff Polska Sp. z o.o. Nowiny Cement Plant. The study results obtained in 2019 were compared with those obtained in 1978 and 2005. The most attention was paid to soil pH; CaCO3 content; organic carbon and nitrogen content; concentrations of available components such as P2O5, K2O and Mg; and the saturation level of sorption complex with alkaline cations. It was found that long-term imission of pollutants caused significant changes in the basic soil properties, which remain in soils despite the evident decrease in the cement-lime dust emission. These include high pH values, excessive CaCO3 content, high soil saturation with alkaline cations and decreases in total carbon content, which were especially visible in soil humus horizons.

Light- or Dark-Colored, L-DOPA-Based Melanins

2018 ◽  
Author(s):  
Koen Vercruysse ◽  
Margaret M. Whalen
Keyword(s):  
Human Physiology ◽  
Ir Spectra ◽  
Immune Cells ◽  
Chemical Properties ◽  
Chemical Signature ◽  
Ft Ir

<p>This report is a continuation of previous research on the H<sub>2</sub>O<sub>2</sub>-mediated synthesis of melanin-like pigments. We synthesized and characterized L-DOPA-based pigments using air- or H<sub>2</sub>O<sub>2</sub>-mediated<sub> </sub>oxidation. We compared their physic-chemical properties and evaluated their capacity to affect the interleukin release from immune cells. The use of higher concentrations of H<sub>2</sub>O<sub>2</sub> resulted in melanin-like materials with a distinct chemical signature in their FT-IR spectra and a lighter color. All pigments enhanced the interleukin release from immune cells. The possibility that lighter-colored melanins can be generated is discussed in the context of the importance of melanin-based pigmentation in human physiology.</p>

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