Photochemical Transformations of Benzo[<i>e</i>]pyrene in Solution and Adsorbed on Silica Gel and Alumina Surfaces

Fioressi, Silvina E.; Arce, Rafael

doi:10.1021/es049192e

Cited by 36 publications

(26 citation statements)

References 30 publications

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“…Furthermore, in the silica of smaller pore size (2.5 nm), the emission intensity of 1,8-DNP was much smaller and broader than for the 6.0 nm pore diameter. Similar decreases in emission intensity with decreasing silica pore size have been observed for other PAHs (Sotero and Arce, 2004; Arce and Fioressi, 2005). …”

Section: Resultssupporting

confidence: 82%

Phototransformations of dinitropyrene isomers on models of the atmospheric particulate matter

Arce

Morel

2013

Atmospheric Environment

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The 1,6 and 1,8-dinitropyrenes (DNP) isomers are strong mutagens and carcinogens encountered in diesel exhaust and airborne particles. Relative photodegradation rates were determined and some products were characterized when these isomers were irradiated adsorbed onto models of the atmospheric matter. These are compared to their photochemical behavior in a polar nonprotic solvent. The 1,8-DNP isomer is three times more reactive than the 1,6-DNP when irradiated adsorbed onto silica gel surfaces, while the reverse order is observed in solution, demonstrating the influence of structural differences and environmental effects on the photoreactivity. Oxygen is a key factor in the formation of pyrenediones from 1,8-DNP in solution and on silica gel which is not the case for 1,6-DNP. The average pore diameter (2.5 versus 6.0 nm) of the silica surfaces induces a significant change in the product distribution and relative yields of 1,8-DNP because pyrenediones or 8-hydroxy-1-nitropyrene are not produced in the smaller pore silica. A 6-hydroxy-1-nitropyrene product is observed both in acidic alumina and silica (6.0 nm) surfaces. On acidic alumina the rates of phototransformation of the isomers are equal, a significant increase in the relative yield of the hydroxynitropyrene product is observed compared to the silica and unidentified products in which the absence of NO2 and pyrene absorption bands were observed, demonstrating the surface effect on the photodegradation. Overall, the presence of some products indicates the occurrence of a nitro-nitrite rearrangement on the surface with the participation of a pyrenoxy radical as their precursor.

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Section: Resultssupporting

confidence: 82%

Phototransformations of dinitropyrene isomers on models of the atmospheric particulate matter

Arce

Morel

2013

Atmospheric Environment

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“…The photoproducts of the adsorbed PAHs have been previously reported. The principal products of BeP photodegradation are diones, diols and hydroxyl derivatives, 9 and for BaP mainly diones. 7 The photodegradation kinetics depends on surface coverage as can be noted from Figure 5.…”

Section: Resultsmentioning

confidence: 99%

“…Condensed PAHs released into the atmosphere are susceptible either to photochemical reaction if exposed to sunlight or to thermal reaction with other pollutants [7]. The microenvironment in which PAHs are adsorbed and their arrangement on particle surfaces affect their spectroscopic and chemical properties [9], and monomer-dimer differences in absorption and emission spectra of some of the smaller PAHs have been studied.…”

Section: Introductionmentioning

confidence: 99%

Effects of cluster formation on spectra of benzo[a]pyrene and benzo[e]pyrene

Fioressi

Binning

Bacelo

2008

Chemical Physics Letters

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Absorption and fluorescence emission spectra of the polycyclic aromatic hydrocarbons benzo [a] pyrene (BaP) and benzo[e]pyrene (BeP) in solution and adsorbed on silica have been obtained and compared to examine the spectroscopic effects of clustering. Molecular mechanics calculations with the UFF potential were done to optimize monomer, dimer and trimer geometries, and energy differences were determined by MP2/6-31G* calculations. Fluorescence emission spectra of adsorbed BeP and BaP display a red shift that progresses with increased loading, and the two differ in their photodegradation kinetics. The experimental and theoretical results are found to be consistent.

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“…Lower mixing heights and less dispersion and gaseous diffusion in winter may contribute to high concentrations of PAHs during the winter season [13]. In addition, the photochemical degradation that is usually a significant loss process of PAHs [14][15][16] may be less efficient in winter and also contribute to the higher concentrations. Although the PAHs were significantly lower in this study than literature data, the seasonal variations of PAHs in urban atmospheric particles seemed to be similar with them.…”

Section: Seasonal Variations Of Pahs In Urban Atmospheric Particlesmentioning

confidence: 99%

Study on the size-segregated distribution of 37 species of polycyclic aromatic hydrocarbons in urban atmospheric fine particles of Japan

Wang

Kobayashi

Zhou

et al. 2014

WIT Transactions on Ecology and the Environment

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The size-segregated distribution and seasonal concentrations of polycyclic aromatic hydrocarbons (PAHs) in urban suspended particulate matter (SPM) at the Japan national route 463 in the urban of Saitama city, Japan were investigated using an Andersen high-volume air sampler. Air sampling was carried out from June 2013 to January 2014. 37 species of toxic PAHs such as benzo [j] [a,l]pyrene were measured. It was found that the average concentration of 37 species of particulate PAHs including methyl-PAHs, benzothiophenes and oxy-PAHs from atmospheric oxidation of PAHs collected in the urban of Saitama city was 3.42 to 6.51 ng/m 3 during 2013 sampling campaign periods. 1,8-naphthalic anhydride (1,8-NA) showed the highest concentration among 37 species of PAHs. The concentrations of high molecular PAHs, which were found in all seasons, followed different size distribution, especially with the highest peak in fine particle sizes around 1.1 μm. The concentrations of low-molecular PAHs were not much different with particle sizes. The toxicity analysis indicated that the carcinogenic potency of particulate PAHs primarily existed in the particle size below 1.1 μm. 37 species of PAHs in urban atmospheric fine particles were not only derived from vehicle emission with long range transportation, but also produced by local other anthropogenic sources.

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Photochemical Transformations of Benzo[e]pyrene in Solution and Adsorbed on Silica Gel and Alumina Surfaces

Cited by 36 publications

References 30 publications

Phototransformations of dinitropyrene isomers on models of the atmospheric particulate matter

Phototransformations of dinitropyrene isomers on models of the atmospheric particulate matter

Effects of cluster formation on spectra of benzo[a]pyrene and benzo[e]pyrene

Study on the size-segregated distribution of 37 species of polycyclic aromatic hydrocarbons in urban atmospheric fine particles of Japan

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