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Review date: July 24, 2003
PNNL-SA-27883

Parts and Garment Cleaning
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Fundamental advances in supercritical and liquid carbon dioxide microemulsions and a breakthrough discovery at the University of North Carolina that enabled the design and synthesis of surfactants (polymers) that dissolve in CO2. Liquid carbon dioxide has long been considered as an alternative, nonpolluting, and nonhazardous cleaning solvent. However, as most contaminants do not have good solubility in carbon dioxide, it has had only limited cleaning power—until now.

When the liquid carbon dioxide is combined with the surfactants, a new cleaning system emerges. Soap-like properties are created when these polymers form micelles that trap dirt and carry it away, similar to the way conventional soap works in water. At the end of the cleaning process, the carbon dioxide is returned to a gas, the dirty residues contained, and the surfactant collected. Both the CO2 and the surfactants are recycled for continued cleaning operations.

The advantages of the technology begin with the carbon dioxide, which is abundant, inexpensive, easily available, and much safer for the environment than traditional cleaning solvents. Because the CO2 and surfactants are recycled, no toxic wastes are released, and water supplies are not consumed or affected, many regulatory issues and public concerns can be minimized. And since the parts or materials are dry and ready to go, energy-intensive drying procedures are not needed. With the detergent boost provided by the surfactants, this technology is unparalleled in CO2 cleaning.

A solvent system that is pollution-free and much less hazardous to human health than existing methods and thoroughly cleans the product while preserving its quality overcomes many hurdles faced by a wide range of industries. The merits of this technology were recognized with a Presidential Green Chemistry Challenge Award in 1997.

Parts Cleaning Competitive Matrix Garmet Care Competitive Matrix

Protecting the environment can be a costly responsibility for many businesses, especially if it means compromising the quality of the products or services they offer. But the health of the planet cannot wait forever! Fighting pollution is the legacy handed over to industry for the new century by the industrial practices established in the past. Addressing that legacy, the CO2-based solvent systems were designed to equal or better the performance of chlorinated solvents and other alternatives without affecting the ozone layer, contaminating the surroundings, risking harmful health effects, or depleting natural resources. This one-of-a-kind, cost-competitive, industrial cleaning method is a milestone for the environment and for industry alike.