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Macrocyclic Receptors for Sensing the Environmentally Important Gaseous Molecules
Published in Satish Kumar, Priya Ranjan Sahoo, Violet Rajeshwari Macwan, Jaspreet Kaur, Mukesh, Rachana Sahney, Macrocyclic Receptors for Environmental and Biosensing Applications, 2022
Satish Kumar, Priya Ranjan Sahoo, Violet Rajeshwari Macwan, Jaspreet Kaur, Mukesh, Rachana Sahney
Benzene is listed among the most harmful VOCs because it is recognized as a human carcinogen by the US Environmental Protection Agency and by the European Commission. (USEPA DWC, 2009). (EC AQS 2015). Long-term exposure to higher concentrations of benzene can be toxic to the liver, kidneys, central nervous system and eyes. However, exposure to BTEX, at normal atmospheric concentrations, or slightly higher concentrations over a short period, is unlikely to cause significant health damage.
Modeling contaminant transport and biodegradation in groundwater
Published in Domy C. Adriano, Alex K. Iskandar, Ishwar P. Murarka, Contamination of Groundwaters, 2020
Hanadi S. Rifai, Philip B. Bedient
The Traverse City field site is a US Coast Guard Air Station located in Grand Traverse County in the northwestern portion of the lower peninsula of Michigan (Figure 12). The groundwater at the site is contaminated with organic chemicals from a source near the Hangar/Administration building. In the upper reach of the plume, hydrocarbons occur at the surface of the water table and move downward in the aquifer as the plume migrates toward east Grand Traverse Bay (Twenter et al. 1985). The soils at the site are generally free of contamination except near the source area. The major contaminants at the site include BTX.
Overview of Gas Plant Processing
Published in Arthur J. Kidnay, William R. Parrish, Daniel G. McCartney, Fundamentals of Natural Gas Processing, 2019
Arthur J. Kidnay, William R. Parrish, Daniel G. McCartney
Raw natural gas can contain compounds in low concentrations that may require removal for environmental, product specification, or processing reasons. Helium is a valuable trace component, but recovery typically is uneconomical unless the concentration is above 0.5 vol%. A brief description of helium recovery processes is given in Chapter 14. The chapter also discusses the removal of other trace components, including BTEX (benzene, toluene, ethylbenzene, and xylenes), methanol, and mercury. BTEX is primarily an environmental concern because of possible emissions from some commonly used gas treating and dehydration units that concentrate them. Although occurring at extremely low concentrations in the gas, elemental mercury can cause mechanical failure in aluminum heat exchangers. Both BTEX and mercury are toxic.
VOC and PAH characterization of petroleum coke at maximum thermal decomposition temperature
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2019
Didem N. Inceoğlu, İsmail Özbay, Aykan Karademir
Emissions to the atmosphere are another important concern since coke production is among the most-polluting production processes, especially with respect to particulate matter, sulfur dioxide, and organics emissions resulted from the thermal degradation of coal blend at high temperatures (1,000–1,200°C) (Malça and Freire 2011). For the organic emissions, volatile organic compounds (VOCs) and polyaromatic hydrocarbons (PAHs) emissions have a special importance due to the adverse health effects including carcinogenicity. According to WHO (1984) coke oven gas (COG) includes hydrogen, methane, ethane, carbon monoxide, ammonia, carbon dioxide, hydrogen sulfide, ethylene, propylene, butylene, acetylene, oxygen, and nitrogen. The tar fraction of the COG includes creosote oil, pyridine, naphthalene, tar acids, and coal-tar pitch. The light-oil fraction (BTX) includes benzene, toluene, and xylene (WHO 1984). Therefore, there are many studies on VOC and PAH emissions of coke oven process (Coerc 2016; Fermoso et al. 2010), but the effect of petcoke addition to the coal blend on these emissions was studied rarely. Some articles studied the volatile percentage of petcoke when used as an additive to coal blend in the coke-making process (Fermoso et al. 2010), while others were focused on the PAH emissions (Coerc 2016).
Nonionic surfactant enhanced biodegradation of m-xylene by mixed bacteria and its application in biotrickling filter
Published in Journal of the Air & Waste Management Association, 2018
Liping Wang, Ruiwei Xu, Bairen Yang, Shaohua Wei, Ningning Yin, Chun Cao
Benzene, toluene, ethylbenzene, and xylene (BTEX) is a group of highly typical volatile organic compounds (VOCs). BTEX are commonly found in coal tar, crude petroleum, and a wide range of petroleum-based products (Long and Zhang 2015). The VOCs are the precursors for the formation of ozone, secondary aerosol, and photochemical smog when emitted into the atmosphere (Shao, Zhang, and Zeng 2009). BTEX exert crucial adverse effects on the atmospheric environment (Lau and Chan 2003). As suspected carcinogenic and/or mutagenic substances, BTEX can also pose threats to organismal and human health (Schiavon, Ragazzi, and Torretta 2016). Among the BTEX compounds, xylene, including o-, m-, and p-xylene isomers, is widely used as organic solvent and chemical raw material. The toxic effects of xylene on the liver, kidneys, and the central nervous system once the compound enters the body by skin contact or inhalation have been reported.
Screening of xylene degrading bacteria and optimization of their degradation characteristics in heavily polluted areas
Published in Environmental Technology, 2022
Jinxuan Zhang, Xiaodan Fan, Hao Zhang, Yinbing Tang, Jiaying Zhou, Xueqi Wang, Zhengtong Yuan
Volatile organic compounds (VOCs), as one of the main sources of air pollution, such as ozone (O3) pollution and excessive PM2.5 [1,2], mainly include alkanes, aromatics, esters, aldehydes and others, with benzene, toluene and xylene as typical representatives [3]. According to the integrated emission standard of air pollutants GB 16297–1996 (China), various VOCs have different emission standards, and different countries and regions have strict restrictions on the emission of VOCs. Volatile organic compounds, such as benzene, toluene and xylene, are collectively referred to as BTEX. BTEX is highly volatile. The harm is enormous, which pollutes the environment and most BTEX waste gases are toxic, causing cancer and teratogenesis to a certain extent [4]. Long-term excessive inhalation will cause a serious impact on human health [5]. Then xylene in BTEX is a very typical VOCs and widely exists in the environment [6,7], which mainly comes from the field of the organic chemical industry, such as printing, painting, coating, petroleum processing, and so on [8]. Xylene is volatile to the atmospheric environment during production, storage, and use, thereby seriously affecting regional ambient air quality [9]. In addition, xylene can also stimulate the sensory organs of humans and animals, resulting in different degrees of toxic effects. For example, xylene can irritate the eyes and the upper respiratory tract and even has an anesthetic effect on the central nervous system at high concentrations [10,11]. Therefore, the control of BTEX in VOCs, especially xylene, has been paid more and more attention by various countries.