Ethyl benzene pollutant

As illustrated by Table 3 aromatic compounds such as toluene, benzene, 0, m, p-xylenes and ethyl benzene are important pollutants in urban air. These compounds comprise a substantial fraction of automotive fuel and its use results in substantial emissions of aromatic compounds into urban atmo-... 

The list (see Appendix 6.1) contains 170 substances said to have the potential to cause significant water pollution. The majority are not solvents. The important solvents included on the list are the major chlorinated hydrocarbons toluene ortho, meta and para xylenes ethyl benzene and some long chain aliphatics (C8 upwards). Pollution authorities in EU member states refer to this list in setting their own national lists for control. 

Another major group of chemicals commonly encountered in conjimction with groundwater pollution are a group of LNAPLs referred to as the BTEX (benzene, toluene, ethyl benzene, and xylene) compounds. The BTEX compoimds are derived from petroleum, are major constituents in gasoline and other petroleum products, and represent a significant environmental concern with respect to pollution of the subsurface. 

The separation of these environmental pollutants (benzene, toluene, ethyl benzene and xylenes) from aliphatic hydrocarbon mixtures is challenging since these hydrocarbons have boiling points in a close range and several combinations form azeotropes. 

Unbumt gasoline and cracked hydrocarbons such as ethylene and propylene are also substantial constituents of exhaust. Gasoline contains additives such as benzene, toluene and branched hydrocarbons to achieve the necessary octane numbers. The direct emission of these volatile compounds, e.g. at gas stations, is a significant source of air pollution. Leaded fuels, containing antiknock additions such as tetra-ethyl-lead, have been abandoned because lead poisons both human beings and the three-way exhaust catalyst, especially for the removal of NO by rhodium. 

One of the major uses of activated carbon is in the recovery of solvents from industrial process effluents. Dry cleaning, paints, adhesives, polymer manufacturing, and printing are some examples. Since, as a result of the highly volatile character of many solvents, they cannot be emitted directly into the atmosphere. Typical solvents recovered by active carbon are acetone, benzene, ethanol, ethyl ether, pentane, methylene chloride, tetrahydrofuran, toluene, xylene, chlorinated hydrocarbons, and other aromatic compounds [78], Besides, automotive emissions make a large contribution to urban and global air pollution. Some VOCs and other air contaminants are emitted by automobiles through the exhaust system and also by the fuel system, and activated carbons are used to control these emissions [77,78],... 

Chabazite (Ca,Na)2[Al2Si40f2] 6H20 (Rgure 14a) absorbs the vapors of small molecules such as water, formic acid, methyl and ethyl alcohols, but not large molecules such as aceton, ether, benzene or SO2 from pollutants of smokestacks ... 

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