scholarly journals An improved catalytic pyrolysis concept for renewable aromatics from biomass involving a recycling strategy for co-produced polycyclic aromatic hydrocarbons

2019 ◽  
Vol 21 (14) ◽  
pp. 3802-3806 ◽  
Author(s):  
Homer C. Genuino ◽  
Inouk Muizebelt ◽  
André Heeres ◽  
Niels J. Schenk ◽  
Jos G. M. Winkelman ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Crude Glycerol ◽  
Catalytic Pyrolysis ◽  
Zeolite Catalyst ◽  
Polycyclic Aromatic ◽  
Benzene Toluene

Catalytic pyrolysis of crude glycerol over a shaped H-ZSM-5 zeolite catalyst with (partial) recycling of the product oil was studied with the incentive to improve benzene, toluene, and xylene (BTX) yields.

scholarly journals Identification and quantification of organic pollutants in the air of the city of Astana using solid phase microextraction

2017 ◽  
pp. 14-17
Author(s):  
Dina Orazbayeva ◽  
Ulzhalgas Karatayeva ◽  
Kulzhan Beysembayeva ◽  
Kulyash Meyramkulova
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Ambient Air ◽  
Average Concentration ◽  
Polycyclic Aromatic ◽  
Benzene Toluene ◽  
The City

Solid-phase microextraction in combination with gas chromatography and mass-spectrometry (GC-MS) was used for determination of benzene, toluene, ethylbenzene and o-xylene (BTEX), polycyclic aromatic hydrocarbons (PAH), and for identification of volatile organic compounds (VOCs) in ambient air of the city of Astana, Kazakhstan. The screening of the samples showed the presence of mono- and polycyclic aromatic hydrocarbons, alkanes, alkenes, phenols, and benzaldehydes. The concentrations of naphthalene were 5-7 times higher than the permissible value, it was detected in all studied air samples. Average concentration of naphthalene was 18.4 μg/m3, acenaphthylene – 0.54 μg/m3, acenaphthene – 1.63 μg/m3, fluorene – 0.79 μg/m3, anthracene – 3.27 μg/m3, phenanthrene – 0.22 μg/m3, fluorantene – 0.74 μg/m3, pyrene – 0.73 μg/m3. Average concentrations of BTEX in the studied samples were 31.1, 84.9, 10.8 and 11.6 μg/m3, respectively. Based on the statistical analysis of the concentrations of BTEX and PAH, the main source of city air pollution with them was assumed to be vehicle emissions.

scholarly journals Aryl-CoA Ligases, subfamily of the adenylate-forming enzyme superfamily

2021 ◽  
Author(s):  
M. E. Arnold ◽  
I. Kaplieva-Dudek ◽  
I. Heker ◽  
R. U. Meckenstock
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Environmental Conditions ◽  
Aromatic Compounds ◽  
Metabolic Pathways ◽  
Coa Ligase ◽  
Enzyme Superfamily ◽  
Polycyclic Aromatic ◽  
Benzene Toluene ◽  
Enzyme Class

Aryl-CoA ligases belong to class I of the adenylate-forming enzyme superfamily (ANL superfamily) and catalyze the formation of thioester bonds between aromatic compounds and Coenzyme A (CoA) and occur in nearly all forms of life. These ligases are involved in various metabolic pathways degrading benzene, toluene, ethylbenzene, and xylene (BTEX) or polycyclic aromatic hydrocarbons (PAHs). They are often necessary to produce the central intermediate benzoyl-CoA that occurs in various anaerobic pathways. The substrate specificity is very diverse between enzymes within the same class, while the dependency on Mg 2+ , ATP and CoA as well as oxygen insensitivity are characteristics shared by the whole enzyme-class. Some organisms employ the same aryl-CoA ligase when growing aerobically and anaerobically, while others induce different enzymes depending on the environmental conditions. Aryl-CoA ligases can be divided into two major groups, benzoate:CoA ligase-like enzymes and phenylacetate:CoA ligase-like enzymes. They are widely distributed between the phylogenetic clades of the ANL superfamily and show closer relations within the subfamilies than to other aryl-CoA ligases. This, together with residual CoA-ligase activity in various other enzymes of the ANL superfamily, leads to the conclusion that CoA ligases might be the ancestral proteins from which all other ANL superfamily enzymes developed.

scholarly journals Research on the Release of Dangerous Compounds from the BTEX and PAHs Groups in Industrial Casting Conditions

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2581
Author(s):  
Mariusz Holtzer ◽  
Rafał Dańko ◽  
Sylwester Piasny ◽  
Michał Kubecki ◽  
Dariusz Drożyński ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Phenol Formaldehyde ◽  
Green Sand ◽  
Casting Alloys ◽  
Furan Resin ◽  
Polycyclic Aromatic ◽  
Benzene Toluene ◽  
The Individual

The assessment of the harmfulness of moulding and core sands is mainly based on investigations of compositions of gases emitted by liquid casting alloys during the mould pouring. The results of investigations of moulding sands obtained under industrial conditions are presented in this paper. A unique research stand was designed and built for this aim. It allowed us to determine emissions of gases at individual stages of casting a mass up to 50 kg. This approach enables simulation of foundry conditions. Moulding sands bound by organic binders (phenol-formaldehyde; furan), inorganic binders and green sand, were subjected to investigations. The composition of gases that evolved during the individual stages, pouring, cooling and knocking out, was tested each time, and the contents of Polycyclic Aromatic Hydrocarbons (PAHs) and benzene, toluene, ethylbenzene, and xylenes (BETX) were analysed. Investigations indicated that the emission of gases from sands with inorganic binders is negligible when compared with the emission of gases from sands with organic binders. The emission of gases from green sand is placed in the middle of the scale. As an example: the sand with furan resin emitted 84 mg of BTEX (in recalculation for 1 kg of sand) while from sands with inorganic binders there was a maximum of 2.2 mg (for 1 kg of sand). In the case of sands with inorganic binders, MI and MC sands indicated comparable and very low emissions of gases from the PAHs group, at the level of 0.018 mg and 0.019 mg for 1 kg of sand, respectively. The higher emission of PAHs from MG sand is the result of its different way of hardening (a binder was of an organic character) than of sands MI and MC.

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