New method for recovering pricey nanoparticles

Julian Eastoe and colleagues point out that scientists are seeking better ways to recover and reuse nanoparticles, which are barely 1/50,000th the width of a human hair. Without that technology, manufacturing processes that take advantage of nanoparticles' unusual properties might be prohibitively expensive. Recovering and recycling nanoparticles is especially difficult because they tend to form complex, hard-to-separate mixtures with other substances.

Eastoe and colleagues describe the development of a special type of microemulsion -- a mixture of oil and water (mayonnaise is an edible emulsion) -- that may solve this problem. In laboratory tests using cadmium and zinc nanoparticles, they showed how the oil and water in the microemulsion separated into two layers when heated. One layer contained nanoparticles that could be recovered and the other contained none. The separation process is reversible and the recovered particles retain their shape and chemical properties, which is crucial for their reuse, the scientists note.