Nanotechnology: Manufacturing Change One Molecule at a Time

WASHINGTON, DC, September 8, 2003 (ENS) - An ultrafine powder made from iron, one of the most abundant metals on Earth, can be used to clean up contaminated soil and groundwater at thousands of landfills, abandoned mines and industrial sites in the United States, a scientific team funded by the National Science Foundation has found.

The so-called "nanoscale" iron particles - about 1/80,000 of the diameter of a human hair - can be suspended in a slurry and pumped straight into the core of a contaminated site like an industrial scale hypodermic injection. Once there, the particles will flow along with the groundwater to decontaminate the site.

This is far cheaper than digging out the soil and treating it shovelful by shovelful, which is how contamination problems are often handled today.

Across the country more than a thousand Superfund sites where hazardous waste is uncontrolled or abandoned, are still untreated. Nanoscale iron could help resolve contamination issues at these sites.

A report on eight years of pioneering work on nanoscale iron and how it can be used to clean up the environment appears in the September 3 issue of the "Journal of Nanoparticle Research."

The research project was funded by the National Science Foundation as part of the federal government's multi-agency national nanotechnology initiative. Nanotechnology is the emerging discipline that seeks to control and manipulate matter on a molecular scale.

According to Lehigh University environmental engineer Wei-xian Zhang, who headed the research project, iron's cleansing power stems from the fact that it rusts, or oxidizes.


Wei-xian Zhang is associate professor of civil and environmental engineering at the P.C. Rossin College of Engineering and Applied Science at Lehigh University. (Photo courtesy Lehigh University)
Contaminants such as trichloroethene, carbon tetrachloride, dioxins or PCBs are caught up in the oxidizing reaction and break down into less toxic simple carbon compounds.

The oxidizing iron also reduces dangerous heavy metals such as lead, nickel, mercury or even uranium into an insoluble form that tends to stay locked in the soil, rather than spreading through the food chain.

Nanoscale iron treatments currently cost about $50 per kilogram, far less than the $500 per kilogram cost of such treatments in 1995, when Zhang and his colleagues first developed a chemical route for making the particles. Zhang is currently forming a company to mass produce the ultrafine iron particles.

Nanotechnology has often been hailed as a "transformative" technology - one that could change the way we live and work as profoundly as did the microchip or the automobile. Decontamination of Superfund sites sounds like a nanotech function with no down-side, but other applications might have unintended consequences that are disturbing, such as molecular computers or molecular robotic arms.

The National Science Foundation (NSF) says that is why it and 16 other federal agencies are supporting the national nanotechnology initiative, at a cost of nearly $1 billion a year.

Nanotechnology is taking off in many directions in labs around the world.

Disease is often caused by damage at the molecular and cellular level. Nanotechnology will let scientists build fleets of computer controlled molecular tools much smaller than a human cell and built with accuracy and precision. For the first time, these tools will be able to clear obstructions in the circulatory system, or kill cancer cells one by one.

Researchers from the University of Pennsylvania and the University of Sheffield have created tree-like molecules that assemble themselves into precisely structured building blocks of a quarter-million atoms. Such building blocks may be precursors to designing nanostructures for molecular electronics or photonics materials, which steer light in the same way computer chips steer electrons.

Nanosys Inc. has announced that a team led by company co-founder Dr. Paul Alivisatos, a chemicstry professor at the University of California-Berkeley, has discovered a nano-material for the efficient production of solar energy. The nano-composite devices can be produced using inexpensive manufacturing methods and will capture the benefits of solar energy in a way that is more cost effective than traditional technologies.


Carbon nanotubes. These strong structures can be filled with a variety of materials including biological molecules. (Photo credit unknown)
In the Wilson Double Core tennis ball, a nanocomposite coating helps keep it bouncing twice as long as a conventional one.

To determine how nanotechnology may change human society, the NSF has awarded two $1 million grants, that expand the foundation's commitment to study the societal implications of nanotechnology. The grants, announced August 25, will be the largest awards the foundation has devoted to societal implications.

"Like any powerful new technology," says NSF Director Rita Colwell, "nanotech also has the potential for unintended consequences - which is precisely why we can't allow the societal implications to be an afterthought. The program has to build in a concern for those implications from the start."

One grant will go to the University of California-Los Angeles, where sociologist Lynne Zucker and her colleagues will study how newly acquired knowledge about nanotechnology makes its way from the laboratory to the marketplace.

The other grant goes to a team headed by Davis Baird, a philosopher at the University of South Carolina. Baird says technologies that do not consider their impact have a way of coming to grief later on. "Witness the widespread opposition to nuclear energy, and more recently, to genetically modified organisms. So how can we go down a better path with nanotechnology?" asks Baird.

Baird says that students who are trained now in the right interdisciplinary setting - one where technical experts can work with people from fields such as law, journalism, medicine, the humanities, social science, or even science fiction and art - will become a cadre of scientists, engineers and scholars who are used to thinking about the societal and technical problems side-by-side.