scholarly journals Gas chromatography using ice-coated fused silica columns: study of adsorption of sulfur dioxide on water ice

2018 ◽  
Vol 18 (10) ◽  
pp. 7527-7537 ◽  
Author(s):  
Stefan Langenberg ◽  
Ulrich Schurath
Keyword(s):  
Gas Chromatography ◽  
Sulfur Dioxide ◽  
Vertical Displacement ◽  
Fused Silica ◽  
Water Ice ◽  
Temperature Range ◽  
Reaction With Water ◽  
The Impact ◽  
Peak Retention Time ◽  
Established Technique

Abstract. The well established technique of gas chromatography is used to investigate interactions of sulfur dioxide with a crystalline ice film in a fused silica wide bore column. Peak shape analysis of SO2 chromatograms measured in the temperature range 205–265 K is applied to extract parameters describing a combination of three processes: (i) physisorption of SO2 at the surface, (ii) dissociative reaction with water and (iii) slow uptake into bulk ice. Process (ii) is described by a dissociative Langmuir isotherm. The pertinent monolayer saturation capacity is found to increase with temperature. The impact of process (iii) on SO2 peak retention time is found to be negligible under our experimental conditions.By analyzing binary chromatograms of hydrophobic n-hexane and hydrophilic acetone, the premelt surface layer is investigated in the temperature range 221–263 K, possibly giving rise to irregular adsorption. Both temperature dependencies fit simple van't Hoff equations as expected for process (i), implying that irregular adsorption of acetone is negligible in the investigated temperature range. Adsorption enthalpies of −45 ± 5 and −23±2 kJ mol−1 are obtained for acetone and n-hexane.The motivation of our study was to assess the vertical displacement of SO2 and acetone in the wake of aircraft by adsorption on ice particles and their subsequent sedimentation. Our results suggest that this transport mechanism is negligible.

scholarly journals Gas-Chromatography using ice coated fused silica-columns: Study of adsorption of sulfur dioxide on water-ice

2017 ◽  
Author(s):  
Stefan Langenberg ◽  
Ulrich Schurath
Keyword(s):  
Gas Chromatography ◽  
Sulfur Dioxide ◽  
Vertical Displacement ◽  
Fused Silica ◽  
Experimental Conditions ◽  
Water Ice ◽  
Temperature Range ◽  
Reaction With Water ◽  
The Impact ◽  
Peak Retention Time

Abstract. The well-established technique of gas chromatography is used to investigate interactions of sulfur dioxide with a crystalline ice film in a fused silica wide-bore column. Peak shape analysis of SO2 chromatograms measured in the temperature range 205–265 K is applied to extract parameters describing a combination of three processes: (i) physisorption of SO2 at the surface; (ii) dissociative reaction with water; (iii) slow uptake into bulk ice. Process (ii) is described by a dissociative Langmuir isotherm. The pertinent monolayer saturation capacity is found to increase with temperature. The impact of process (iii) on SO2 peak retention time is found to be negligible under our experimental conditions. By analyzing binary chromatograms of hydrophobic n-hexane and hydrophilic acetone, the premelt surface layer is probed in the temperature range 221–263 K possibly giving rise to irregular adsorption. Both temperature dependencies fit simple van't Hoff equations as expected for process (i), implying that irregular adsorption of acetone is negligible in the probed temperature range. Adsorption enthalpies of −45 ± 5 kJ mol−1 and −23 ± 2 kJ mol−1 are obtained for acetone and n-hexane. Our study was motivated to assess the vertical displacement of SO2 and acetone in the wake of aircraft by adsorption on ice particles and their subsequent sedimentation. Our results suggest that this transport mechanism is negligible.

Adsorption of organics on thermally treated solids obtained from colloidal silica

1987 ◽  
Vol 52 (3) ◽  
pp. 572-581 ◽  
Author(s):  
Miroslav M. Kopečni ◽  
Slobodan K. Milonjic ◽  
Wladyslaw Rudzinski ◽  
Jacek Jagiello
Keyword(s):  
Gas Chromatography ◽  
Thermodynamic Parameters ◽  
Adsorption Isotherms ◽  
Colloidal Silica ◽  
Adsorption Properties ◽  
Thermal Pretreatment ◽  
Lateral Interactions ◽  
Adsorbed Molecules ◽  
Temperature Range ◽  
Thermally Treated

Adsorption isotherms of three adsorbates on the solid beads obtained from colloidal silica were determined by means of gas chromatography at low surface coverages, when lateral interactions between the adsorbed molecules are negligible. The influence of thermal pretreatment on the adsorption properties of the solids was investigated in the temperature range from 343 to 423 K, while the solids were heated between 523 K and 1 223 K. The thermodynamic parameters of adsorption have been determined and used to discuss the adsorbate-adsorbent interactions.

Determination of multi pesticide residues in leaf and needle samples using a modified QuEChERS approach and gas chromatography-tandem mass spectrometry

2021 ◽  
Author(s):  
Arnelle Löbbert ◽  
Sonja Schanzer ◽  
Henrik Krehenwinkel ◽  
Franz Bracher ◽  
Christoph Müller
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Tandem Mass Spectrometry ◽  
Forest Ecosystems ◽  
Tandem Mass ◽  
Modified Quechers ◽  
Chromatography Tandem Mass Spectrometry ◽  
The Impact ◽  
Impact Of Pesticides

A novel, validated QuEChERS-based GC-MS/MS method was developed, which will allow the assessment of the impact of pesticides on forest ecosystems.

scholarly journals Reservoir-Induced Land Deformation: Case Study from the Grand Ethiopian Renaissance Dam

2021 ◽  
Vol 13 (5) ◽  
pp. 874
Author(s):  
Yu Chen ◽  
Mohamed Ahmed ◽  
Natthachet Tangdamrongsub ◽  
Dorina Murgulet
Keyword(s):  
Land Surface ◽  
Large Scale ◽  
Surface Deformation ◽  
Vertical Displacement ◽  
Nile River ◽  
Reservoir Volume ◽  
Novel Approach ◽  
Land Deformation ◽  
Large Scale Land ◽  
The Impact

The Nile River stretches from south to north throughout the Nile River Basin (NRB) in Northeast Africa. Ethiopia, where the Blue Nile originates, has begun the construction of the Grand Ethiopian Renaissance Dam (GERD), which will be used to generate electricity. However, the impact of the GERD on land deformation caused by significant water relocation has not been rigorously considered in the scientific research. In this study, we develop a novel approach for predicting large-scale land deformation induced by the construction of the GERD reservoir. We also investigate the limitations of using the Gravity Recovery and Climate Experiment Follow On (GRACE-FO) mission to detect GERD-induced land deformation. We simulated three land deformation scenarios related to filling the expected reservoir volume, 70 km3, using 5-, 10-, and 15-year filling scenarios. The results indicated: (i) trends in downward vertical displacement estimated at −17.79 ± 0.02, −8.90 ± 0.09, and −5.94 ± 0.05 mm/year, for the 5-, 10-, and 15-year filling scenarios, respectively; (ii) the western (eastern) parts of the GERD reservoir are estimated to move toward the reservoir’s center by +0.98 ± 0.01 (−0.98 ± 0.01), +0.48 ± 0.00 (−0.48 ± 0.00), and +0.33 ± 0.00 (−0.33 ± 0.00) mm/year, under the 5-, 10- and 15-year filling strategies, respectively; (iii) the northern part of the GERD reservoir is moving southward by +1.28 ± 0.02, +0.64 ± 0.01, and +0.43 ± 0.00 mm/year, while the southern part is moving northward by −3.75 ± 0.04, −1.87 ± 0.02, and −1.25 ± 0.01 mm/year, during the three examined scenarios, respectively; and (iv) the GRACE-FO mission can only detect 15% of the large-scale land deformation produced by the GERD reservoir. Methods and results demonstrated in this study provide insights into possible impacts of reservoir impoundment on land surface deformation, which can be adopted into the GERD project or similar future dam construction plans.

scholarly journals INVESTIGASI PENGARUH KONDISI LALU LINTAS DAN ASPEK METEOROLOGI TERHADAP KONSENTRASI PENCEMAR SO2 DI KOTA SEMARANG

2016 ◽  
Vol 13 (1) ◽  
pp. 21
Author(s):  
Titik Istirokhatun ◽  
Ita Tetriana Agustini ◽  
Sudarno Sudarno
Keyword(s):  
Air Pollution ◽  
Sulfur Dioxide ◽  
Human Health ◽  
Adverse Reactions ◽  
Meteorological Factors ◽  
Ambient Air ◽  
Health Problems ◽  
Traffic Light ◽  
Road Users ◽  
The Impact

The  presence  of  air  pollution  in  ambient  air  is  closely  related  to  the incidence  of  adverse reactions affecting human health. One of harmful pollutants and potentially major cause health problems is sulfur dioxide (SO 2 ). The number of vehicles that are passing and queuing on the crossroads  because  of  traffic light can  affect  the  concentration  of  SO 2 .  Besides,  in  these locations  there  are a lot of road users  which  are  potentially  exposed  by  contaminants, so information about the concentration of SO 2  is important to know. This study aimed to investigate the  impact  of  meteorological  factors  and  the  number  of vehicles  on  SO 2   concentrations. Impinger was used for air sampling, and pararosaniline method was used for determining SO 2  concentration. Sampling and calculation  of the number of passing vehicles were performed 3 times ie in the morning, afternoon and evening. Based on the results of the study, the highest concentrations of SO 2  were on the range of 15-21 mg/Nm3.

Determination of the viscosity of levitated droplets at atmospheric temperatures in an electrodynamic trap

2021 ◽  
Author(s):  
Stephanie Jones ◽  
Mohit Singh ◽  
Denis Duft ◽  
Alexei Kiselev ◽  
Thomas Leisner
Keyword(s):  
Amorphous Solid ◽  
Organic Aerosol ◽  
Photochemical Reactions ◽  
Temperature Range ◽  
Ability To Act ◽  
Levitated Droplets ◽  
Semi Solid ◽  
Future Work ◽  
The Impact

<p>The impact of atmospheric aerosol on the climate remains poorly understood. Organic aerosol makes up a significant fraction of total aerosol and is prevalent throughout the atmosphere. It can exist as a liquid, semi-solid or amorphous solid. The viscosity of organic aerosol will have an impact on transformations that organic aerosol will undergo during its lifetime such as evaporation and growth, heterogeneous and photochemical reactions as well as the ability to act as an ice nucleating particle.  Therefore, it is of key importance to be able to determine aerosol viscosity over a range of atmospherically relevant conditions in order to better understand the impact of organic aerosol on the climate.</p> <p>Here we report proof of concept viscosity measurements of water droplets levitated in an electrodynamic balance over a range of temperatures. Charged droplets are levitated in a temperature and relative humidity-controlled environment allowing properties over a temperature range of 300 to 220 K to be studied. As the droplets evaporate they reach a point where Coulomb instabilities are induced resulting in droplet oscillations. The relaxation of these oscillations can then be probed to determine the droplet viscosity. Future work will involve determination of the viscosity of different types of organic aerosol over a broad temperature range.</p>

Aroma profile and lactic acid bacteria characteristic of traditional Slovak cheese “May bryndza”

2021 ◽  
pp. 108201322110399
Author(s):  
Jana Štefániková ◽  
Július Árvay ◽  
Simona Kunová ◽  
Przemysław Łukasz Kowalczewski ◽  
Miroslava Kačániová
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Butanoic Acid ◽  
Aroma Profile ◽  
Volatile Organic ◽  
Ewe's Milk ◽  
The Impact

This paper describes the results of the characterization of a traditional Slovak cheese called “May bryndza” with regard to the profiles of volatile organic compounds and lactic acid bacteria. Samples of “May bryndza“ cheese produced solely from unpasteurized ewe's milk were collected from 4 different Slovak farms, and samples of the cheese produced from a mixture of 2 types of milk (raw ewe's and pasteurized cow's milk) were collected from 3 different Slovak industrial dairies. There were 15 compounds detected and identified by the electronic nose. The impact of the kind of milk and the kind of dairy on the aroma profile of the product was not confirmed by PCA. The compounds with the highest relative contents in samples were acetoin (2.59%–24.55%), acetic acid (6.69%–13.39%), methoxy-phenyl-oxime (4.49%–8.52%), butanoic acid (1.89%–5.67%), and 2,3-butanediol (0.98%–4.08%), which were determined with gas chromatography. A total of 1533 isolates of LAB were obtained from the “May bryndza” cheese samples. Four families, five genera, and 19 species were identified with mass spectrometry, and isolated bacteria, both from the farm and industry dairies were the most frequently found to belong to Lactococcus lactis subsp. lactis.

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