Detection of Benzene, Toluene, Ethyl Benzene, and Xylenes (BTEX) Using Toluene Dioxygenase-Peroxidase Coupling Reactions

2003 ◽  
Vol 19 (6) ◽  
pp. 1812-1815 ◽  
Author(s):  
Z. Xu ◽  
A. Mulchandani ◽  
W. Chen
Keyword(s):  
Ethyl Benzene ◽  
Coupling Reactions ◽  
Toluene Dioxygenase ◽  
Benzene Toluene

scholarly journals Conditions chimiques contrôlant l'atténuation naturelle des BTEX et solvants chlorés : un état des connaissances

2005 ◽  
Vol 14 (4) ◽  
pp. 419-444 ◽  
Author(s):  
O. Atteia ◽  
M. Franceschi
Keyword(s):  
Cette Technique ◽  
Ethyl Benzene ◽  
Benzene Toluene

L'atténuation naturelle des BTEX (Benzène, Toluène, Ethyl-benzène, Xylène) et des solvants chlorés est de plus en plus étudiée en raison des potentialités offertes par cette technique de gestion. Cet article, après avoir présenté les aspects abiotiques de l'atténuation détaille les conditions chimiques nécessaires à la réalisation des réactions de biodégradation des polluants organiques. Les aspects thermodynamiques sont abordés afin de décliner les réactions possibles et celles qui ne le sont pas selon les environnements chimiques. La dégradation des BTEX est focalisée sur le benzène, produit le plus toxique et le moins dégradable sur la plupart des sites. Les détails de la dégradation du benzène sur le terrain sont analysés dans la littérature et leur comparaison permet de décrire les mécanismes responsables de celle-ci. Dans le cas des solvants chlorés, l'attention est portée sur le TCE (Trichloréthylène), produit le plus couramment rencontré sur les sites pollués. Une mise en parallèle des évolutions de teneurs observées et des conditions chimiques locales permet de mettre en évidence les conditions nécessaires à la dégradation du TCE, et de ses congénères, ainsi que les cinétiques de dégradation dans différentes conditions. La mise en évidence du rôle prépondérant des conditions chimiques conduit à remettre en cause l'utilisation répandue des constantes de dégradation du premier ordre et donne des pistes pour les modèles nécessaires à une prédiction plus fine de l'atténuation naturelle.

Aerobic Biodegradation of Aromatic and Chlorinated Hydrocarbons Commonly Detected in Landfill Leachates

1988 ◽  
Vol 23 (3) ◽  
pp. 460-475 ◽  
Author(s):  
Della J. Berwanger ◽  
James F. Barker
Keyword(s):  
Hydrogen Peroxide ◽  
Surface Sediment ◽  
Chlorinated Hydrocarbons ◽  
Aerobic Biodegradation ◽  
Ethyl Benzene ◽  
Landfill Leachates ◽  
Toxic Level ◽  
Benzene Toluene ◽  
Hazardous Organics

Abstract Aromatic and chlorinated hydrocarbons are hazardous organics which persist in groundwater impacted by landfill leachate. Recent studies have indicated that the aromatics biodegrade readily under aerobic conditions. Similarly, methane-oxidizers are reported to metabolize trichloroethylene. This study investigates an in-situ biorestoration scheme involving stimulating aerobic biodegradation in a contaminated anaerobic, methane-saturated groundwater using hydrogen peroxide as an oxygen source. Batch biodegradation experiments were conducted with groundwater and core obtained from the Gloucester Landfill, Ottawa, Canada. Hydrogen peroxide, added at a non-toxic level, provided oxygen which promoted the rapid biodegradation of benzene, toluene, ethyl benzene, o-, m-, and p-xylene. Morphologically different methane-oxidizing cultures were obtained from Gloucester groundwater and a surface sediment. Both cultures degraded trichloroethylene in microcosms containing a mineral media and Gloucester core. Degradation was not observed when the mineral madia was replaced with Gloucester groundwater, or when other chlorinated hydrocarbons were added. Additional research is required to identify and overcome this inhibition to trichloroethylene biodegradation, before this remedial strategy can be employed.

scholarly journals Feasibility of Carbonaceous Nanomaterial-Assisted Photocatalysts Calcined at Different Temperatures for Indoor Air Applications

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Wan-Kuen Jo ◽  
Kun-Hwan Kim
Keyword(s):  
Calcination Temperature ◽  
Indoor Air ◽  
Low Temperatures ◽  
Photocatalytic Decomposition ◽  
Ethyl Benzene ◽  
Multiwall Carbon Nanotube ◽  
Different Temperatures ◽  
Benzene Toluene ◽  
Uv Lamp ◽  
Carbonaceous Nanomaterial

This study examined the characteristics and photocatalytic activity of multiwall carbon nanotube-assisted TiO2(MWNT-TiO2) nanocomposites calcined at different temperatures to assess their potential indoor air applications. It was confirmed that the composites calcined at low temperatures (300 and 400°C) contained TiO2nanoparticles bound intimately to the MWNT networks. Meanwhile, almost no MWNTs were observed when the calcination temperature was increased to 500 and 600°C. The MWNT-TiO2composites calcined at low temperatures showed higher photocatalytic decomposition efficiencies for aromatic hydrocarbons at indoor concentrations than those calcined at high temperatures. The mean efficiencies for benzene, toluene, ethyl benzene, and o-xylene (BTEX) by the composite calcined at 300°C were 32, 70, 79, and 79%, respectively, whereas they were 33, 71, 78, and 78% for the composite calcined at 400°C, respectively. In contrast, the efficiencies decreased to close to zero when the calcination temperature was increased to 600°C. Moreover, the MWNT-TiO2exhibited superior photocatalytic performance for the decomposition efficiencies compared to TiO2under conventional UV-lamp irradiations. Consequently, these carbonaceous nanomaterial-assisted photocatalysts can be applied effectively to indoor air applications depending upon the calcination temperature.

Efficient detection of volatile aromatic hydrocarbon using linseed oil–styrene–divinylbenzene copolymer coated quartz crystal microbalance

RSC Advances ◽  
2015 ◽  
Vol 5 (73) ◽  
pp. 59533-59540 ◽  
Author(s):  
Rashmita Das ◽  
Rajib Bandyopadhyay ◽  
Panchanan Pramanik
Keyword(s):  
Aromatic Hydrocarbon ◽  
Quartz Crystal Microbalance ◽  
Quartz Crystal ◽  
Linseed Oil ◽  
Ethyl Benzene ◽  
Optimum Ratio ◽  
Efficient Detection ◽  
Divinyl Benzene ◽  
Styrene Divinylbenzene ◽  
Benzene Toluene

A polymer film with high sensing ability QCM for benzene, toluene, o-xylene and ethyl benzene vapors has been produced from the co-polymerization of styrene, divinyl benzene and linseed oil with an optimum ratio at 120 °C.

Exposure Assessment to Benzene, Toluene, Ethyl Benzene and Xylene (BTEX) in Gas Stations in Central Region of Iran

2016 ◽  
Vol 13 (1) ◽  
pp. 43-48
Author(s):  
Mehrzad Ebrahemzadih ◽  
Abolfazl Barkhordari Firooz Abadi ◽  
Omid Giahi ◽  
Nasim Tahmasebi
Keyword(s):  
Exposure Assessment ◽  
Central Region ◽  
Ethyl Benzene ◽  
Gas Stations ◽  
Benzene Toluene

scholarly journals The Influence of the Concentration of Cyclohexane Radicals Bonded with an Si100 Silica Gel Surface upon the Retention of Some Hydrocarbons in Gas Chromatography

2000 ◽  
Vol 18 (1) ◽  
pp. 43-53 ◽  
Author(s):  
R. Nasuto
Keyword(s):  
Gas Chromatography ◽  
Silica Gel ◽  
Stationary Phases ◽  
Ethyl Benzene ◽  
Polar Organic Compounds ◽  
Phase Concentration ◽  
Bonded Phase ◽  
Unmodified Silica ◽  
Benzene Toluene ◽  
Ethylene Chloride

Four adsorbents based on silica gel Si100 with chemically bonded cyclohexane have been prepared as stationary phases for gas chromatography. The concentrations of cyclohexane radicals thus bonded with the silica gel surface were 1.35, 3.35, 4.17 and 6.02 μmol/m2, respectively. Separation of aliphatic (C6–C12), aromatic (benzene, toluene and m-xylene) and some polar organic compounds (chloroform, ethylene chloride, chlorobenzene, p-chlorotoluene and ethyl benzene) by gas chromatography using columns packed with the prepared adsorbents was studied. It was concluded that the retention of some compounds was increased on the column packed with an adsorbent of 1.35 μmol/m2 concentration relative to that measured on the column packed with the unmodified silica gel. On columns packed with adsorbents with a higher bonded phase concentration than 1.35 μmol/m2, the retention times of all the compounds studied chromatographically decreased with an increase in the bonded phase concentration.

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