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Technology & Innovation

Environmental and Biological Implications of Nanoparticles

Category: Technology & Innovation

By Will Lynch, Delana Nivens and George C. Shields
Armstrong Atlantic State University

Feb. 8, 2010 – Nanotechnology, or nanotech, is the study of controlling the size of particles on the nanometer scale.  A nanometer is one billionth of a meter and is roughly the size of a marble in comparison to the Earth. Nano means small.  The first hint at the future of “small” was given by Richard Feynman in a 1959 lecture at the American Physical Society meeting at the California Institute of Technology, "There's Plenty of Room at the Bottom."   In this seminal presentation on the topic, Feynman predicted we would learn to manipulate particles on an atom-by-atom basis and that many of the optical and electronic properties would change in this regime.

Nanotech is big business.  The United States National Science Foundation has predicted that the global market for nanotechnologies will reach $1 trillion by 2015.  Current trends indicate a rapidly growing market for nanoparticles in our consumer goods and technology areas, including energy, communications and medicine.  Nanoparticles have been found in Roman pottery as well as medieval stained glass windows.  The technology and ability of scientists to control and fabricate reproducible nanoparticles, however, has just emerged in the past 10 to 15 years.

So, what is the point?  The point is two-fold. In the nanoregime, the fundamental properties of materials all change compared to their bulk counterparts.  For example, copper is a noble metal and can be used in building materials such as water pipes.  On the nanoscale, copper becomes very “hot” and reactive, decomposing in microseconds.  Everyone is familiar with the properties of gold, including its beautiful color and its use in jewelry; yet, on the nanoscale, gold becomes an elegant maroon color.  The other fundamental concept that small enhances is the surface area of structures.  As you get smaller, the relative surface area increases exponentially.  This makes nanoparticles ideal to help design new catalysts, which are molecules that speed up chemical reactions.

When semi-conductors and metal oxides are prepared in the nanoregime, they acquire new properties as a direct result of quantum confinement effects.  These effects begin at sizes smaller than 100 nanometers in diameter.  Human eyes cannot see anything this small, even with the best visible light microscope.  These nanoparticles have increased reactivity, coupled with an increased surface area, resulting in nanoparticle catalysts that are more efficient than conventional catalysts. 

Chemistry students at Armstrong Atlantic State University are being exposed to the latest in high technology science through a project that infuses nanotechnology with the environment.  The project, led by chemistry professors Will Lynch and Delana Nivens, is focused on using the power of light to remediate environmental pollutants.  The pollutants of interest in this study are halogenated hydrocarbons or phenols recognized by the Environmental Protection Agency as priority or “emerging” pollutants.  These compounds are used in pesticides, wood preservatives, and flame-retardants and are known to cause cancer.  Breakdown of these pollutants by direct sunlight in the environment is inherently slow because the compounds’ absorbance spectrum does not overlap well with the solar spectrum.  This slow degradation often results in both bioaccumulation of these compounds and widespread distribution of the compounds in the environment.  Size-controlled nanoparticle catalysts allow for better absorption of the solar spectrum (i.e., visible light) and the potential for fast destruction of these compounds.

Our goals in investigating the photochemistry of nanoparticles are to determine which systems are most efficient for the degradation processes.  We collected data on the dechlorination of two organochlorine compounds, hexachlorobenzene (HCB) and pentachlorophenol (PCP).

Our data shows that dechlorination of zinc sulfide and cadmium sulfide is achieved through 24 hours of visible light using nanoparticles.  PCP is destroyed on zinc sulfide nanoparticles also through 24 hours of exposure to light.
An effective sunlight harvesting photoremediation catalyst must be able to function in complex natural waters containing greater than 20 parts per thousand of chloride and lower concentrations of numerous other ions such as sulfate, nitrite, nitrate, phosphate and carbonate to achieve remediation. Dr. Nivens and Dr. Lynch have extended their studies to investigate the effects of salt solutions on our nanoparticle catalysts.  In summary, their studies have shown that nanoparticles can use visible light sources to degrade environmental pollutants with the potential to operate in real world systems.

George Shields is the dean of the College of Science and Technology at Armstrong Atlantic State University.  He can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it.. Will Lynch is professor of chemistry and department head in the Department of Chemistry & Physics, in the College of Science and Technology, at Armstrong Atlantic State University.  He can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it..  Delana Nivens is an associate professor of chemistry in the Department of Chemistry & Physics, in the College of Science and Technology, at Armstrong Atlantic State University.  She can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it..

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