Spelling suggestions: "subject:"sulphur dioxide"" "subject:"sulphur tioxide""
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Valuing the environmental benefits of reduced acid deposition in the semi-natural environmentMacMillan, Douglas C. January 1996 (has links)
No description available.
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A Determination of the Value of Sulphur Dioxide as a Dehydrating Agent for Sweet PotatoesScogin, Everett Robert 08 1900 (has links)
The purpose of this experiment was to determine the value of sulphur dioxide as a dehydrating agent for sweet potatoes.
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Baseline assessment of the density and diversity of birds around Matimba and Medupi power station / Luckson MuyemekiMuyemeki, Luckson January 2015 (has links)
Bird populations are changing at unprecedented rates in response to human-induced changes to
the global environment, and these rates of change are expected to accelerate over the coming
decades. Changes in the levels of sulphur dioxide (SO2) in the atmosphere through emissions
from power stations pose a potential threat to bird populations. However, avian response to SO2
pollution is poorly understood. Exploring the relationship between avian diversity and SO2
exposure levels will help in determining species sensitive to air pollution.
This study seeks to understand the interactions between avian diversity and SO2 concentration
levels around Matimba power station so as to have more insight on the level of avian vulnerability
to air pollution. Matimba is an important site in South Africa as a second coal fired power station,
Medupi, is currently being constructed with additional stations also a possibility. This study
represents an important baseline assessment of the avian population status before the additional
pollution burden is realised from Medupi.
Ten min repeated point counts were conducted at three sample sites with varying distances from
Matimba and Medupi power stations. These counts were used to calculate bird species density
and diversity. Cloud-free Landsat 8 imagery acquired on 7 January, 2014 was used to derive
habitat structure and productivity variables. Elevation variables were derived using a DEM (Digital
Elevation Model) obtained from NASA Global Data Explorer. The AERMOD dispersion model was
used to characterise spatio-temporal variations in ambient SO2 concentrations around Matimba
power station. Multiple regression analysis was then used to ascertain which of these variables
(SO2, habitat structure, productivity and terrain) contribute most to the observed variation in bird
species density and diversity around Matimba and Medupi power stations.
SO2 polluted air did not have an influence on bird species density and diversity at the community
level. At species level two species (Batis molitor and Streptopelia senegalensis) exhibited some
measure of negative response to SO2 air pollution. However, after further investigation using
multiple regression analysis it was revealed that habitat structure had more influence on the
density of these two species compared with ambient SO2 concentrations. Bird species density
and diversity varied significantly among the sample sites but were not related to the distance to
the source of the SO2 air pollution.
Evidence obtained from this study revealed that continuous monitoring of the interactions
between SO2 polluted air and bird populations is recommended for a more comprehensive
understanding of avian susceptibility towards SO2 air pollution and this will also facilitate in the selection of sensitive and relevant species for future ecology studies at other coal-fired power
stations. Furthermore, it is expected that SO2 concentrations will significantly increase with the
commissioning of Medupi power station thus further necessitating the need for continuous
monitoring of bird species densities around Matimba and Medupi power stations. / MSc (Geography and Environmental Management), North-West University, Potchefstroom Campus, 2015
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Baseline assessment of the density and diversity of birds around Matimba and Medupi power station / Luckson MuyemekiMuyemeki, Luckson January 2015 (has links)
Bird populations are changing at unprecedented rates in response to human-induced changes to
the global environment, and these rates of change are expected to accelerate over the coming
decades. Changes in the levels of sulphur dioxide (SO2) in the atmosphere through emissions
from power stations pose a potential threat to bird populations. However, avian response to SO2
pollution is poorly understood. Exploring the relationship between avian diversity and SO2
exposure levels will help in determining species sensitive to air pollution.
This study seeks to understand the interactions between avian diversity and SO2 concentration
levels around Matimba power station so as to have more insight on the level of avian vulnerability
to air pollution. Matimba is an important site in South Africa as a second coal fired power station,
Medupi, is currently being constructed with additional stations also a possibility. This study
represents an important baseline assessment of the avian population status before the additional
pollution burden is realised from Medupi.
Ten min repeated point counts were conducted at three sample sites with varying distances from
Matimba and Medupi power stations. These counts were used to calculate bird species density
and diversity. Cloud-free Landsat 8 imagery acquired on 7 January, 2014 was used to derive
habitat structure and productivity variables. Elevation variables were derived using a DEM (Digital
Elevation Model) obtained from NASA Global Data Explorer. The AERMOD dispersion model was
used to characterise spatio-temporal variations in ambient SO2 concentrations around Matimba
power station. Multiple regression analysis was then used to ascertain which of these variables
(SO2, habitat structure, productivity and terrain) contribute most to the observed variation in bird
species density and diversity around Matimba and Medupi power stations.
SO2 polluted air did not have an influence on bird species density and diversity at the community
level. At species level two species (Batis molitor and Streptopelia senegalensis) exhibited some
measure of negative response to SO2 air pollution. However, after further investigation using
multiple regression analysis it was revealed that habitat structure had more influence on the
density of these two species compared with ambient SO2 concentrations. Bird species density
and diversity varied significantly among the sample sites but were not related to the distance to
the source of the SO2 air pollution.
Evidence obtained from this study revealed that continuous monitoring of the interactions
between SO2 polluted air and bird populations is recommended for a more comprehensive
understanding of avian susceptibility towards SO2 air pollution and this will also facilitate in the selection of sensitive and relevant species for future ecology studies at other coal-fired power
stations. Furthermore, it is expected that SO2 concentrations will significantly increase with the
commissioning of Medupi power station thus further necessitating the need for continuous
monitoring of bird species densities around Matimba and Medupi power stations. / MSc (Geography and Environmental Management), North-West University, Potchefstroom Campus, 2015
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Pressure Dependence of Line Widths of Microwave Spectra of Sulphur DioxideYang, Wei Han 12 1900 (has links)
Measurements of line width parameters for eleven rotational transitions of type (J -- J + 1) of SO2 were made and are reported herein. The line width quantum number (J) trend was obtained. The microwave spectrograph used for these measurements of line width is described. Operational methods to operate the spectrograph are presented and discussed, with particular attention given to how to measure the line width. Suggestions for future avenues of probing this molecule to ascertain the non-uniform behavior of the line width parameter over the quantum number and frequency range are given.
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Environmental and host factors associated with persistent lower respiratory tract symptoms or asthma following acute environmental exposure to sulphur dioxide (S02).Baatjies, Roslynn 23 February 2007 (has links)
Student Number : 0316118X -
MPH research report -
School of Public Health -
Faculty of Health Sciences / Introduction: On the weekend of 16 – 17 December 1995, the community of Macassar
was exposed to elevated levels of sulphur dioxide vapours (SO2) caused by a fire on a
nearby stockpile for approximately 21.5 hours. It has been estimated that community
members were exposed to levels as high as 200 parts per million (ppm) of this gas as
some 15 000 tons of the sulphur stockpile ignited. This resulted in a toxic plume of SO2
being blown over the Macassar area by the prevailing wind. The aim of this study was to
assess the environmental and host factors associated with persistent lower respiratory
symptoms among residents of this community six years after being acutely exposed to
elevated exposures of SO2 vapours.
Materials and methods: A case-control study was conducted. The cases and controls
were selected from adult residents who reported to the Macassar disaster project clinic for
a health assessment in order to lodge a medico-legal claim. Survey instruments included a
questionnaire, clinical examination and clinical record review by an expert panel. A case
was defined as an adult resident who presented to the clinic for an examination with
persistent (at year 1 and 6 after the disaster) lower respiratory symptoms. Controls were
chosen from clinic attendees without lower respiratory symptoms at year 1 and 6.
Environmental exposure was calculated by using the Industrial Source Complex Short
Term Model (ISCST 3) to predict time-averaged concentrations at specified receptor
locations. Multiple logistic regression was used to investigate the association between
lower persistent respiratory symptoms, host and environmental factors (estimated
concentration and duration of exposure to SO2). Results: A total of 76 cases and 180 controls were selected. The cases and controls were
comparable with respect to age, gender, height and smoking status. The results indicated
that a medical history of pulmonary tuberculosis at least one year prior to the fire (OR:
3.5, CI: 1.5-8.4) was significantly associated with having persistent lower respiratory
symptoms. Furthermore, subjects with persistent lower respiratory symptoms were nine
times more likely to report symptoms of tight chest (OR: 9.9; CI: 5.2-19.1), and twice as
likely to report shortness of breath (OR: 2.0; CI: 1.0-4.1) at the time of the fire. None of
the exposure metrics (total hours of exposure, cumulative exposure, peak exposure) were
significantly associated with persistent lower respiratory symptoms. However, peak SO2
exposure estimated at hour 15 was significantly associated with persistent lower
respiratory symptoms (OR: 1.0; CI: 1.0-1.1).
Discussion: The results of this study are consistent with previous studies reporting lower
respiratory tract symptoms after chemical exposure irrespective of age or smoking status.
Furthermore, as in other studies respiratory health status was a significant factor in
determining susceptibility to SO2 exposure. Various reports in the literature suggest that
exposure > 20 ppm is associated with chronic respiratory symptoms. This however was
not demonstrated in this study, using estimates of exposure calculated using the ISCST
model suggesting possible exposure misclassification. “Self-selection” bias was an
important limitation in this study, since the entire study population was self-referred and
as such the study population was not randomly selected. Another limitation is the
possibility that there may be potential recall bias operating since the fire incident
happened six years ago; however this was considered unlikely as there was nondifferential
reporting between cases and control. Self reported symptoms on the
questionnaires might have been over-reported due to fear, anxiety and stress or secondary gain related to compensation issues. The lack of association between exposure variables
and persistent asthma may have also been due to lack of power (small sample size),
although this was thought to be a minor contributory factor.
Conclusion: Host-related factors such as a previous history of pulmonary TB and acute
asthma-like symptoms at the time of the fire were important predictors of persistent lower
respiratory symptoms reported by residents 6 years after acute exposure to SO2 vapours
emanating from a sulphur fire.
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SO2/O2 as an oxidant in hydrometallurgyWensheng Zhang January 2000 (has links)
Abstract is not available
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Photochemical assessment of oceanic emissions of DMS and its oxidation to SO₂ based on airborne field observationsShon, Zang-Ho 12 1900 (has links)
No description available.
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SO2 and O2 separation by using ionic liquid absorption / S.L. RabieRabie, Samuel Liversage January 2012 (has links)
In order to reduce the amount of pollution that is generated by burning fossil fuels alternative
energy sources should be explored. Hydrogen has been identified as the most promising
replacement for fossil fuels and can be produced by using the Hybrid Sulphur (HyS) cycle.
Currently the SO2/O2 separation step in the HyS process has a large amount of knock out
drums. The aim of this study was to investigate new technology to separate the SO2 and O2.
The technology that was identified and investigated was to separate the SO2 and O2 by
absorbing the SO2 into an ionic liquid.
In this study the maximum absorption, absorption rate and desorption rate of SO2 from the
ionic liquid [BMIm][MeSO4] with purities of 95% and 98% was investigated. These ionic liquid
properties were investigated for pure O2 at pressures ranging from 1.5 to 9 bar(a) and for
pure SO2 at pressures from 1.5 to 3 bar(a) at ambient temperature. Experiments were also
carried out where the composition of the feed-stream to the ionic liquid was varied with
compositions of 0, 25, 50, 75 and 100 mol% SO2 with O2 as the balance. For each of these
compositions the temperature of the ionic liquid was changed from 30oC to 60oC, in
increments of 10oC.
The absorption rate of SO2 in the ionic liquid increased when the mole percentage SO2 in the
feed stream was increased. When the temperature of the ionic liquid was decreased the
maximum amount of SO2 that the ionic liquid absorbed increased dramatically. However, the
absorption rate was not influenced by a change in the absorption temperature.
The experimental results for the maximum SO2 absorption were modelled with the Langmuir
absorption model. The model fitted the data well, with an average standard deviation of
17.07% over all the experiments. In order to determine if the absorption reaction was
endothermic or exothermic the Clausius-Clapeyron equation was used to calculate the heat
of desorption for the desorption step. The heat of desorption data indicated that the
desorption of SO2 from this ionic liquid was an endothermic reaction because the heat of
desorption values was positive. Therefore the absorption reaction was exothermic.
From the pressure-change experiments the results showed that the mole percentage of O2
gas that was absorbed into the ionic liquid was independent of the pressure of the O2 feed.On the other hand, there was a clear correlation between the mole percentage SO2 that was
absorbed into the ionic liquid and the feed pressure of the SO2. When the feed pressure of
the SO2 was increased the amount of SO2 absorbed also increased, this trend was
explained with Fick’s law.
In the study the effect of the ionic liquid purity on the SO2 absorption capacity was
investigated. The experimental results for the pressure experiments showed that the 95%
and 98% pure ionic liquid absorbed about the same amount of SO2. During the temperature
experiments the 95% pure ionic liquid absorbed more SO2 than the 98% pure ionic liquid for
all but two of the experiments. However the 95% pure ionic liquid also absorbed small
amounts of O2 at 30 and 40oC which indicated that the 95% pure ionic liquid had a lower
selectivity than the 98% pure ionic liquid. Therefore, the 95% pure ionic liquid had better SO2
absorption capabilities than the 98% pure ionic liquid.
These result showed that the 98% pure ionic liquid did not absorb more SO2 than the 95%
pure ionic liquid, but it did, however, show that the 98% pure ionic liquid had a better
selectivity towards the SO2. Hence, it can be concluded that even with the O2 that is
absorbed it would be economically more advantageous to use the less expensive 95% pure
ionic liquid rather than the expensive 98% pure ionic liquid, because the O2 would not
influence the performance of the process negatively in such low quantities. / Thesis (MIng (Chemical Engineering))--North-West University, Potchefstroom Campus, 2013
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Separation of SO2/O2 using membrane technology / Bongibethu Msekeli Hlabano-MoyoHlabano-Moyo, Bongibethu Msekeli January 2013 (has links)
The Hybrid Sulphur process is one technology out of a multitude of known technologies responsible for hydrogen production. Within the latter hydrogen production cycle, it is pivotal to recover O2 as a by-product from a sulphuric acid decomposition reaction that produces SO2, H2O and O2. It is assumed that a simple phase separation stage carried out on the reaction products would liberate SO2 and O2 as a gaseous mixture leaving behind H2O in the liquid state.
Several separation technologies are available to effect SO2/O2 separation, but membrane technology has proved to be dearer due to simplicity of the technology, low capital and energy costs. It is a pity though that insignificant work has been done that considers the SO2/O2 binary system in the membrane technology context. Of the insignificant work done, non – commercial membranes were employed. It is on the latter background that the present study was proposed.
Six commercial membranes were selected from literature, two (Udel Polysulfone and Teflon AF 2400) of which are currently used in gas separation applications and the remainder (Hyflon M, Hyflon F, Halar and Nafion 117) not necessarily used as gas separation membranes but present a potential of separating SO2/O2. The inclusion of the latter four membranes sought to unearth unknown gas separation potentials of the membranes based on hypothetical 1 μm thick membranes.
A screening technique was employed to eliminate poor performing membranes through pure component permeation of SO2, O2, N2 and CO2. The use of the additional gases (N2 and CO2) was meant to allow the generation of a pool of data that would be used as a yardstick to compare to literature and thus validate the authenticity of the designed set up. The single permeation experiments were carried out at 25°C and at absolute gas feed pressures of 1 bar, 2 bar and 3 bar, with the exception of Hyflon F experiments that were carried out at 3.85 bar, 2.85 bar and 1.85 bar also at 25°C. The effect of pressure on gas permeability and ideal selectivity of all gases against O2 was investigated. Udel Polysulfone and Nafion 117 presented clearly evident pressure dependant SO2 permeabilities whilst CO2, N2 and O2 permeabilities were sluggishly dependant on pressure in all membranes. Gas flux in general increased with increasing pressure as pressure is essentially the driving force for permeability. Membrane screening for further investigation was then performed based on a compromise between SO2/O2 ideal selectivity and SO2 flux in hypothetical 1 μm thick membranes. Membranes that presented the best SO2/O2 selectivity include, Udel Polysulfone with SO2/O2 selectivities of 46, 58 and 314 at 1 bar, 2 bar and 3 bar respectively, Nafion 117 with SO2/O2 selectivities of 30, 35 and 40 at 1 bar, 2 bar and 3 bar respectively and Halar with a SO2/O2 selectivity of 17 at 3 bar. The best SO2 flux through hypothetical 1 μm thick membranes was manifested in Teflon AF 2400 with SO2 fluxes of 3.6 m3.m-2.hr-1, 5.9 m3.m-2.hr-1 and 9.9 m3.m-2.hr-1 at trans-membrane pressures of 1 bar, 2 Bar and 3 Bar respectively, Udel Polysulfone with SO2 fluxes of 0.13 m3.m-2.hr-1, 0.32 m3.m-2.hr-1 and 2.56 m3.m-2.hr-1 at trans-membrane pressures of 1 bar, 2 bar and 3 bar respectively and Nafion 117 with SO2 fluxes of 0.48 m3.m-2.hr-1, 1.03 m3.m-2.hr-1 and 1.79 m3.m-2.hr-1 at 1 bar, 2 bar and 3 bar trans-membrane pressures respectively. Despite Teflon AF 2400 presenting the highest SO2 flux, the poor SO2/O2 ideal selectivity ≈ 1 rendered the membrane unfit for further investigation. The low SO2 flux (0.02 m3.m-2.hr-1) presented by Halar also rendered the membrane unfit for further investigation despite the relatively fair SO2/O2 ideal selectivity of 17.
Binary permeation experiments were then performed on Udel Polysulfone and Nafion 117 after passing the single permeation screening test. Gas mixture compositions of (25 wt %:75 wt %, SO2:O2), (50 wt %:50 wt %, SO2:O2) and (75 wt %:25 wt %, SO2:O2) were employed. The binary permeation experiments were carried out at a temperature range of 15°C to 55°C and a SO2 feed partial pressure range of 1.1 ± 0.1 bar to 2.3 ± 0.1 bar.
The SO2 permeate composition increased with pressure and decreased with temperature in both Udel Polysulfone and Nafion 117. Udel Polysulfone presented a superior SO2/O2 separation potential, concentrating a (25 wt %:75 wt %, SO2:O2) gas mixture to (94 wt %:6 wt %, SO2:O2) in a single step at 15°C and 2.2 ± 0.1 bar SO2 feed partial pressure. Nafion 117 concentrated the same gas mixture to (87 wt %:13 wt %, SO2:O2) also in a single step at 15 °C and 2.4 ± 0.1 bar SO2 feed partial pressure. Based on hypothetical 1 μm thick membranes, Nafion 117 presented generally high SO2 molar fluxes in mixture with O2 of about a magnitude higher than the SO2 molar fluxes presented in Udel Polysulfone. Also, Nafion 117 proved to be less prone to plasticisation within the pressure range considered. Despite Udel Polysulfone presenting generally lower SO2 molar fluxes, Udel Polysulfone was deemed to be the ideal membrane for the current SO2/O2 separation application as thicknesses of 1 μm of Nafion the perfluorosulfonic acid based membrane are currently unknown and also Udel Polysulfone presented the best SO2/O2 separation capability. The latter findings are envisaged to prompt further research on the production of ultra-thin perfluoro-sulfonic acid based membranes for the current application. / Thesis (MIng (Chemical Engineering))--North-West University, Potchefstroom Campus, 2013
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