The Removal of Benzene in Isopentane

Benzene is a common contaminant of a variety of fuels such as gasoline. Its removal from the atmosphere is important given its cancer-causing potential and human health hazard. Techniques used to extract benzene and other organic pollutants from air include biofiltration, which incorporates the solvent isopentane as a supporting media.

Benzene

• Benzene is a well-known byproduct of burning fossil fuels such as coal and oil. The aromatic compound has use in the chemical manufacturing of detergents, pesticides and plastics. Its carcinogenicity links it to conditions such as leukemia and also affects blood and bone marrow production. This occurs anywhere between less than five to 30 years of regular exposure to benzene. Exposure to high amounts of benzene over a short time induces unconsciousness, and may be fatal.

Isopentane

• Isopentane is a flammable hydrocarbon solvent comprised of branched pentane compounds. It is mainly used in aerosol propellants, blowing agents and in gas-phase polymerization as an internal coolant. Impurities found in isopentane include traces of benzene and other aromatic compounds. Isopentane is a compound of choice in the air biofiltration process.

Air Biofiltration

• Air biofiltration involves the degradation of volatile organic compounds using microorganisms. It is usually combined with techniques such as air stripping or vacuum extraction to remove benzene from groundwater and soil. Biofiltration involves the use of biofilters, consisting of microbes fixed to a bioflm using supporting media such as isopentane.

Isopentane in Biofiltration

• The use of isopentane optimizes the biofiltraton process by providing additional support to the biofilter. This is largely due to its aqueous solubility properties and its octanol-water partition coefficient. Researchers from the United States Environmental Protection Agency used isopentane in the comparison of biodegradation rates among a range of biofilters.