Photocatalytical oxidation of de-icing agents in aqueous solutions and aqueous extract of jet fuel

2001 ◽  
Vol 44 (5) ◽  
pp. 1-6 ◽  
Author(s):  
Krichevskaya M. ◽  
Malygina T. ◽  
Preis S. ◽  
Kallas J.
Keyword(s):  
Titanium Dioxide ◽  
Aqueous Solutions ◽  
Aqueous Extract ◽  
Jet Fuel ◽  
Military Bases ◽  
Oh Radicals ◽  
Oh Radical ◽  
Heavy Pollution ◽  
Shallow Ponds

Improper handling of jet fuel at abandoned military bases has resulted in heavy pollution of the soil and groundwater. Experimental research of photocatalytical oxidation (PCO) of jet fuel aqueous extract and aqueous solutions of de-icing agents was undertaken. The influence of different parameters - pH, concentration of substances to be oxidised, presence of inorganic admixtures, effect of OH• radical generators - on the PCO of solutions of de-icing agents and jet fuel aqueous extract was determined. The role of OH• radicals was found to be less important in determining the PCO rate. The PCO of organic pollutants was also investigated using a catalyst immobilised onto the surface of buoyant hollow glass micro-spheres. Attached titanium dioxide (TiO2) showed lower photocatalytical activity than when suspended in slurry, although it allows waters to be treated in simple shallow ponds without intensive stirring. The biodegradability of aqueous solutions of de-icing agents and jet fuel aqueous extract increased as PCO proceeded.

scholarly journals Influence of relative humidity and temperature on the production of pinonaldehyde and OH radicals from the ozonolysis of α-pinene

2010 ◽  
Vol 10 (15) ◽  
pp. 7057-7072 ◽  
Author(s):  
R. Tillmann ◽  
M. Hallquist ◽  
Å. M. Jonsson ◽  
A. Kiendler-Scharr ◽  
H. Saathoff ◽  
...  
Keyword(s):  
Gas Phase ◽  
Degradation Mechanism ◽  
Product Distribution ◽  
Major Product ◽  
Radical Formation ◽  
Oh Radicals ◽  
Oh Radical ◽  
Significant Difference ◽  
Dry Conditions

Abstract. The ozonolysis of α-pinene has been investigated under dry and humid conditions in the temperature range of 243–303 K. The results provided new insight into the role of water and temperature in the degradation mechanism of α-pinene and in the formation of secondary organic aerosols (SOA). The SOA yields were higher at humid conditions than at dry conditions. The water induced gain was largest for the lowest temperatures investigated (243 and 253 K). The increase in the SOA yields was dominated by water (and temperature) effects on the organic product distribution, whilst physical uptake of water was negligible. This will be demonstrated for the example of pinonaldehyde (PA) which was formed as a major product in the humid experiments with total molar yields of 0.30±0.06 at 303 K and 0.15±0.03 at 243 K. In the dry experiments the molar yields of PA were only 0.07±0.02 at 303 K and 0.02±0.02 at 253 K. The observed partitioning of PA as a function of the SOA mass present at 303 K limited the effective vapour pressure of pure PA pPA0 to the range of 0.01–0.001 Pa, 3–4 orders of magnitude lower than literature values. The corresponding mass partitioning coefficient was determined to KPA=0.005±0.004 m3 μg−1 and the total mass yield αPAtotal=0.37±0.08. At 303 K PA preferably stayed in the gas-phase, whereas at 253 K and 243 K it exclusively partitioned into the particulate phase. PA could thus account at least for half of the water induced gain in SOA mass at 253 K. The corresponding effect was negligible at 303 K because the PA preferably remained in the gas-phase. The yield of OH radicals, which were produced in the ozonolysis, was indirectly determined by means of the yield of cyclohexanone formed in the reaction of OH radicals with cyclohexane. OH yields of the α-pinene ozonolysis were determined to 0.67±0.17 for humid and 0.54±0.13 for dry conditions at 303 K, indicating a water dependent path of OH radical formation. For 253 and 243 K OH yields could be estimated to 0.5 with no significant difference between the dry and humid experiments. This is the first clear indication for OH radical formation by α-pinene ozonolysis at such low temperatures.

scholarly journals Influence of relative humidity and temperature on the production of pinonaldehyde and OH radicals from the ozonolysis of α-pinene

2010 ◽  
Vol 10 (2) ◽  
pp. 3129-3172 ◽  
Author(s):  
R. Tillmann ◽  
M. Hallquist ◽  
Å. M. Jonsson ◽  
A. Kiendler-Scharr ◽  
H. Saathoff ◽  
...  
Keyword(s):  
Gas Phase ◽  
Degradation Mechanism ◽  
Product Distribution ◽  
Major Product ◽  
Radical Formation ◽  
Oh Radicals ◽  
Oh Radical ◽  
Significant Difference ◽  
Dry Conditions

Abstract. The ozonolysis of α-pinene has been investigated under dry and humid conditions in the temperature range of 243–303 K. The results provided new insight into the role of water and temperature in the degradation mechanism of α-pinene and in the formation of secondary organic aerosols (SOA). The SOA yields were higher at humid conditions than at dry conditions. The water induced gain was largest for the lowest temperatures investigated (243 and 253 K). The increase in the SOA yields was dominated by water (and temperature) effects on the organic product distribution, whilst physical uptake of water was negligible. This will be demonstrated for the example of pinonaldehyde (PA) which was formed as a~major product in the humid experiments with total molar yields of 0.30±0.06 at 303 K and 0.15±0.03 at 243 K. In the dry experiments the molar yields of PA were only 0.07±0.02 at 303 K and 0.02±0.02 at 253 K. The observed partitioning of PA as a function of the SOA mass present at 303 K limited the effective vapour pressure of pure PA pPA0 to the range of 0.01–0.001 Pa, 3–4 orders of magnitude lower than literature values. The corresponding mass partitioning coefficient was determined to KPA=0.005±0.004 m3/μg and the total mass yield αPA.total=0.37±0.08. At 303 K PA preferably stayed in the gas-phase, whereas at 253 K and 243 K it exclusively partitioned into the particulate phase. PA could thus account at least for half of the water induced gain in SOA mass at 253 K. The corresponding effect was negligible at 303 K because the PA preferably remained in the gas-phase. The yield of OH radicals, which were produced in the ozonolysis, was indirectly determined by means of the yield of cyclohexanone formed in the reaction of OH radicals with cyclohexane. OH yields of the α-pinene ozonolysis were determined to 0.67±0.17 for humid and 0.54±0.13 for dry conditions at 303 K, indicating a water dependent path of OH radical formation. For 253 and 243 K OH yields could be estimated to 0.5 with no significant difference between the dry and humid experiments. This is the first clear indication for OH radical formation by α-pinene ozonolysis at such low temperatures.

Role of OH radicals in radiolytic conversion of desoxyribonucleoproteid complex in aqueous solutions

1973 ◽  
Vol 22 (5) ◽  
pp. 1128-1129
Author(s):  
V. A. Sharpatyi ◽  
N. V. Zakatova ◽  
D. R. Minkhadzhidinova ◽  
S. M. Yarovaya ◽  
L. I. Kudryashov
Keyword(s):  
Aqueous Solutions ◽  
Oh Radicals

On the Structure of Lead(II) Complexes in Aqueous Solutions. I. Trinuclear Clusters

1995 ◽  
Vol 60 (4) ◽  
pp. 527-536 ◽  
Author(s):  
Martin Breza ◽  
Alena Manová
Keyword(s):  
Quantum Chemistry ◽  
Aqueous Solutions ◽  
Electronic Structures ◽  
Mndo Method ◽  
Model Systems ◽  
Trinuclear Clusters ◽  
The Stability ◽  
Semiempirical Mndo

Using semiempirical MNDO method of quantum chemistry the optimal geometries and corresponding electronic structures of [Pb3(OH)n]6-n model systems as well as of their hydrated [Pb3(OH)n(H2O)8-n]6-n analogues (n = 4, 5) are investigated. The most stable trinuclear lead(II) complexes present in aqueous solutions correspond to cyclo-(μ3-OH)(μ2-OH)3Pb32+, Pb(μ-OH)2Pb(μ-OH)2Pb2+, cyclo-(μ3-OH)2(μ2-OH)3Pb3+, Pb(OH)(μ-OH)2Pb(μ-OH)Pb(OH)+ and Pb(OH)(μ-OH)2Pb(μ-OH)2Pb+ systems. The key role of OH bridges (by vanishing direct Pb-Pb bonds) on the stability of individual isomers is discussed.

scholarly journals The role of nodose ganglia in the regulation of cardiovascular function following pulmonary exposure to ultrafine titanium dioxide

2013 ◽  
Vol 8 (4) ◽  
pp. 447-454 ◽  
Author(s):  
Hong Kan ◽  
Zhongxin Wu ◽  
Yen-Chang Lin ◽  
Teh-Hsun Chen ◽  
Jared L Cumpston ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Cardiovascular Function ◽  
Pulmonary Exposure ◽  
Nodose Ganglia

Delivery of Electrons by Proton-Hole Transfer in Ice at 10 K: Role of Surface OH Radicals

2021 ◽  
pp. 704-710
Author(s):  
Kensei Kitajima ◽  
Yoichi Nakai ◽  
W. M. C. Sameera ◽  
Masashi Tsuge ◽  
Ayane Miyazaki ◽  
...  
Keyword(s):  
Oh Radicals ◽  
Hole Transfer
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