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Super and Subcritical Extraction Technologies

The EERC has been conducting groundbreaking work for 20 years to understand the chemistry of water and carbon dioxide under pressurized super- and subcritical conditions. The EERC is a world leader in manipulating the properties of subcritical water to allow for selective extraction, separation, and destruction or sequestration of select organic chemicals. Extraction technologies have been applied to flavor and fragrance compounds, antioxidants, and pharmaceutical compounds from plants; contaminants from soils; polymer additives from packaging materials; destruction of explosives; mimicking the bioavailability of pollutants in soils; and dechlorinization of polyvinyl chloride.

Global Expertise

  • Two U.S. patents
  • More than 140 peer-reviewed publications
  • Twelve peer-reviewed book chapters
  • More than 150 invited lectures in the United States, Canada, Europe, Australia, New Zealand, and the Far East
  • Three international and several national awards for "research excellence" and "contributions to the scientific community"
  • Collaborative research and publication with researchers from more than 20 countries and all continents except Antarctica

Supercritical Fluid Extraction (SFE)

The EERC is a world leader in understanding the chemistry of water and CO2 under pressurized and heated (supercritical and subcritical) conditions for the extraction and separation of organic compounds that are not efficiently extracted without the use of hazardous organic solvents.

Benefits

  • SFE reduces the time needed for the extraction and concentration of organic compounds.
  • Environmentally friendly solvents like carbon dioxide and water can replace hazardous organic solvents.
  • The solvent strength of carbon dioxide and water can be controlled over a broad range of extraction pressures and temperatures.
  • Supercritical fluids have lower viscosities and higher solute diffusivities than liquid solvents, thus enhancing mass transfer.
  • Extracts from supercritical carbon dioxide and subcritical water can be directly used for pharmacological and toxicological testing.

Available Pumping Systems

  • ISCO 100D and 260D

Subcritical Water Extraction

The EERC leads the world in manipulating the properties of subcritical water to allow for selective extraction, separation, and destruction or sequestration of select organic chemicals.

Water is a notoriously poor solvent for most organic pollutants such as polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and most pesticides. Supercritical water (temperature >3740C, pressure >221 atm) is an excellent solvent for such pollutants but is extremely corrosive. The EERC has demonstrated that the polarity of water can be controlled over a wide range by simply heating under enough pressure (a few atmospheres) to maintain the liquid state. With temperature control up to 350oC, water can perform very selective extractions of polar (at lower temperatures), moderately polar, and nonpolar (at higher temperatures) organic pollutants from contaminated soils and waste sludges. Complete removal of a wide variety of organic pollutants from real-world samples has been demonstrated with only a few minutes of subcritical water extraction.

Subcritical water can also be used to destroy reactive organic pollutants such as the explosives in many pesticides and PCBs. Soils treated in this manner are fertile and have greatly reduced toxicity.

The EERC has constructed several laboratory-scale systems to perform subcritical water extractions and reactions and one pilot-scale (8-L) unit. Removal of high concentrations of carcinogenic PAHs and the rapid destruction of several pesticides and explosives have been demonstrated with this system.

Subcritical Water Extraction Projects

  • Fundamental solubility and mechanism studies.
  • The development of subcritical water extraction as a replacement for hazardous and toxic solvents used for analytical extractions.
  • Pilot-scale demonstrations of remediation applications.
  • Fractionation of organic and inorganic pollutants from air particulates and contaminated soils to identify toxic components that cannot be studied by conventional methods.

Useful Links

Environmental Chemistry Laboratory

EERC Publications