scholarly journals Processes of chemical transformations in heavy aromatic hydrocarbons of the Surakhan oil under the action of UV rays

2021 ◽  
Vol 2064 (1) ◽  
pp. 012108
Author(s):  
U J Yolchuyeva ◽  
R A Jafarova ◽  
V M Abbasov ◽  
N I Mursalov ◽  
G A Hajiyeva ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Atmospheric Oxygen ◽  
Oxidation Products ◽  
Chemical Transformations ◽  
Atmospheric Conditions ◽  
Oxidative Reactions ◽  
Polycyclic Aromatic ◽  
Aromatic Components ◽  
Uv Rays

Abstract Photooxidative transformations and mechanisms of oxidative reactions in aromatic groups of hydrocarbons isolated from heavy Surakhan (Azerbaijan) petroleum under atmospheric conditions have been investigated. Polycyclic aromatic hydrocarbons, which are part of the aromatic components of heavy Surakhan petroleum, after irradiation with UV rays for 1÷11 hours in the presence of oxygen undergo chemical transformations: endoperoxides polycyclic aromatic hydrocarbons, quinones, etc. are formed. It was found that oxidation products under atmospheric conditions can be formed as follows: during the oxidation of acenes (naphthalene, anthracene), which are part of the aromatic groups of petroleum components, excited aromatic hydrocarbons (donor) interact with atmospheric oxygen (acceptor) in the triplet state with the transition of the acceptor to excited state with the formation of singlet oxygen 1O2, in this case the donor molecule returns to the ground state. When phenanthrene is photooxidized, quinones are formed (the reaction is irreversible).

Continuous Ozonation of Polycyclic Aromatic Hydrocarbons in Oil/Water-Emulsions and Biodegradation of Oxidation Products

1999 ◽  
Vol 40 (4-5) ◽  
pp. 107-114 ◽  
Author(s):  
A. Kornmüller ◽  
U. Wiesmann
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Biological Treatment ◽  
Reaction Rate ◽  
Oxidation Products ◽  
Direct Reaction ◽  
Biological Degradation ◽  
Polycyclic Aromatic ◽  
Oil Water ◽  
Treatment Step

The continuous ozonation of polycyclic aromatic hydrocarbons (PAH) was studied in a two stage ozonation system followed by serobic biological degradation. The highly condensed PAH benzo(e)pyrene and benzo(k)fluoranthene were oxidized selectiely in synthetic oil/water-emulsions. The influence of the ozone mass transfer gas-liquid on the reaction rate of benzo(k)fluoranthene was studied for process optimization. The dissolved ozone concentration is influenced by temperature to a higher degree than the reaction rate of PAH. In dependence on pH, PAH oxidation occurs by a direct reaction with ozone inside the oil droplets. Two main ozonation products of benzo(e)pyrene were quantified at different retention times during ozonation and their transformation could be shown in the biological treatment step.

scholarly journals Characterization of a Novel Angular Dioxygenase from Fluorene-Degrading Sphingomonas sp. Strain LB126

2007 ◽  
Vol 74 (4) ◽  
pp. 1050-1057 ◽  
Author(s):  
Luc Schuler ◽  
Sinéad M. Ní Chadhain ◽  
Yves Jouanneau ◽  
Christine Meyer ◽  
Gerben J. Zylstra ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Oxidation Products ◽  
Initial Attack ◽  
Gram Positive ◽  
Sequence Identity ◽  
Polycyclic Aromatic ◽  
Angular Dioxygenase

ABSTRACT In this study, the genes involved in the initial attack on fluorene by Sphingomonas sp. strain LB126 were investigated. The α and β subunits of a dioxygenase complex (FlnA1-FlnA2), showing 63 and 51% sequence identity, respectively, to the subunits of an angular dioxygenase from the gram-positive dibenzofuran degrader Terrabacter sp. strain DBF63, were identified. When overexpressed in Escherichia coli, FlnA1-FlnA2 was responsible for the angular oxidation of fluorene, 9-hydroxyfluorene, 9-fluorenone, dibenzofuran, and dibenzo-p-dioxin. Moreover, FlnA1-FlnA2 was able to oxidize polycyclic aromatic hydrocarbons and heteroaromatics, some of which were not oxidized by the dioxygenase from Terrabacter sp. strain DBF63. The quantification of resulting oxidation products showed that fluorene and phenanthrene were the preferred substrates of FlnA1-FlnA2.

Year-long variability of polycyclic aromatic hydrocarbons (PAHs) and their contribution to winter intense pollution events in the urban environment of Athens, Greece 

2021 ◽  
Author(s):  
Irini Tsiodra ◽  
Kalliopi Tavernaraki ◽  
Aikaterini Bougiatioti ◽  
Georgios Grivas ◽  
Maria Apostolaki ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Biomass Burning ◽  
Aromatic Hydrocarbons ◽  
Fine Particulate Matter ◽  
The Other ◽  
Oxidation Products ◽  
Atmospheric Composition ◽  
The European Union ◽  
Development Fund ◽  
Polycyclic Aromatic

<p>Polycyclic aromatic hydrocarbons (PAHs) are organic pollutants with proven mutagenic and carcinogenic potential that originate from incomplete combustion, and partition to fine particulate matter. Nitro-PAHs & oxy-PAHs are oxidation products of PAHs with increased toxicity compared to their parent members and may reveal useful information about the aging and oxidation processes of PAHs.</p><p>In this study, we investigate the seasonal profiles of 31 PAHs and select oxidized forms such as nitro PAHs & quinones in Athens, Greece to understand their sources, levels, toxicity and impacts. PAHs levels were found to be significantly higher during winter, particularly during intense pollution episodes, compared to the other seasons. Chemical markers linked to biomass burning (BB) emissions are found to correlate well with the total amount of PAHs (ΣPAHs) during wintertime, strongly indicating that BB emissions are a significant source of PAHs. Positive Matrix Factorization (PMF) analysis showed that more than 50% of ΣPAHs originate from BB emissions and that a “factor” (composed of a specific mixture of PAHs) characterizes biomass burning emissions – and can potentially be used as a tracer. Analysis of the PMF series suggests that BB aerosol is much more carcinogenic than the effects of gasoline and diesel combustion combined. Finally, the exposure impact during winter is 9 times higher compared with the other seasons.</p><p> Acknowledgements</p><p>This work has been funded by the European Research Council, CoG-2016 project PyroTRACH (726165) H2020-EU.1.1. – Excellent. We also acknowledge support by the “PANhellenic infrastructure for Atmospheric Composition and climatE change” (MIS 5021516) implemented under the Action “Reinforcement of the Research and Innovation Infrastructure ”, funded by the Operational Programme “Competitiveness, Entrepreneurship and Innovation” (NSRF 2014-2020) and co-financed by Greece and the European Union (European Regional Development Fund).</p><p> </p>

scholarly journals Characteristics and Sources of Environmentally Persistent Free Radicals in PM2.5 in Dalian: Important Role of Polycyclic Aromatic Hydrocarbons

2021 ◽  
Author(s):  
Zhansheng Li ◽  
Hongxia Zhao ◽  
Xintong Li ◽  
Tadiyose Girma Bekele
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Free Radicals ◽  
Aromatic Hydrocarbons ◽  
Airborne Particulate Matter ◽  
Mean Value ◽  
Biomass Combustion ◽  
Atmospheric Conditions ◽  
Secondary Sources ◽  
Polycyclic Aromatic

Abstract Environmentally persistent free radicals (EPFRs) are an emerging class of environmental hazardous contaminants that extensively, stably exist in airborne particulate matter and pose harmful effects on human health. However, there was little research about the sources of EPFRs in actual atmospheric conditions. This study reported the occurrence, characteristics and sources of EPFRs and polycyclic aromatic hydrocarbons (PAHs) in PM2.5 collected in Dalian, China. The concentrations of PM2.5-bound EPFRs ranged from 1.13×1013 to 8.97×1015 spins/m3 (mean value: 1.14×1015 spins/m3). Carbon-centered radicals and carbon-centered radicals with adjacent oxygen atoms were detected. The concentration of ∑PAHs ranged from 1.09 to 76.24 ng/m3 and PAHs with high molecular weight (HMW) were predominant species in PM2.5. The correlation analysis and PMF result showed that coal and biomass combustion are the top contributors to EPFR, followed by vehicle emission. The secondary sources to EFPRs was negligible. The finding of present study provides an important evidence for further study on the formation mechanism of EPFRs in actual atmospheric to control the air pollution.

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