Size Does Matter - When it Comes to Reducing Environmental Pollution

PASADENA, Calif.-When it comes to mitigating the harmful impacts of environmental pollution--size does matter . . . or, at least, that's the hypothesis that California Institute of Technology professors Janet Hering and Richard Flagan will be testing.

Hering is professor of environmental science and engineering executive officer for Keck Laboratories. Flagan is executive officer of chemical engineering Irma and Ross McCollum professor of chemical engineering and professor of environmental science and engineering.

In a study funded by the Camille and Henry Dreyfus Foundation, Hering and Flagan will examine whether the effectiveness of iron nanoparticles in pollution remediation is influenced by their size. The $120,000 grant, under the Dreyfus Foundation's 2004 Postdoctoral Program in Environmental Chemistry, will be used to recruit a postdoctoral scientist to conduct research in environmental chemistry.

Specifically, the researchers will utilize this grant to examine effective strategies for reduction and mitigation of environmental pollutants in aquatic ecosystems. Ultimately, the study seeks to help provide viable, cost-effective commercial technologies for the remediation of certain contaminants, including groundwater contaminants, chlorinated solvents, nitrates, pesticides, various chemical by-products, residue created in manufacturing, and other industrial or inorganic contaminants.

The study, "Use of Vapor-Phase Synthesized Iron Nanoparticles to Examine Nanoscale Reactivity," will investigate whether reactivity and effectiveness of iron nanoparticles, in pollution mitigation, are influenced by their size. The study will compare particles in different size classes to determine whether nanoparticles exhibit enhanced reactivity in the reduction of organic substrates based on their size when surface area effects are accounted for.

Elemental iron [Fe(0)], or zero-valent iron, has been demonstrated to be an effective reductant for a wide range of environmental contaminants, including both organic and inorganic contaminants. Upon reaction with Fe(0), some contaminants can be transformed to products that are non-toxic or immobile. Fe(0) can be delivered to the subsurface environment by injection of Fe(0) nanoparticles.

If research results yield a conclusion that the size of Fe(0) nanoparticles does make a difference in their reactivity or effectiveness, then this finding will have a significant effect on the application of Fe(0) materials in environmental remediation and will provide insight into the fundamental chemical properties and behavior of nanoparticles in these applications.

Created in 1946, the Camille and Henry Dreyfus Foundation bears the names of modern chemistry pioneers Drs. Camille Dreyfus and his brother Henry. The foundation's mandate is "to advance the science of chemistry, chemical engineering, and related sciences as a means of improving human relations and circumstances throughout the world." The foundation directs much of its resources to the support of excellence in teaching and research by outstanding chemistry faculty at universities and colleges.