Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How minerals react in the environment depends on particle size

31.03.2004


One of the most common groups of minerals on earth is the iron oxides, found in soils, rusting iron, and the dust of Mars.



Due to their importance in the environment, iron oxide minerals have been widely studied, providing insight into their properties and reactivities. But when the size of minerals decreases to 1 to 10 nanometers (billionths of a meter), many of their properties change. Andrew Madden of Blacksburg, a Ph.D. student in geosciences at Virginia Tech, will report on the nanoscale properties of iron oxide at the 227th national meeting of the American Chemical Society, being held in Anaheim, Calif., March 28 through April 1, 2004.

"Geoscientists now recognize that there are small particles in our environment, but we don’t know their properties at the nanoscale," says Madden. He is doing his experiments using hematite, the same iron oxide associated with Mars.


He is studying the reaction between dissolved manganese and oxygen, a process known as manganese oxidation. The rate of the reaction is greatly enhanced by minerals such as hematite. This process is responsible for removing dissolved manganese from water and forming manganese oxide minerals, which are extremely important in adsorbing and transforming a variety of pollutants, such as lead, nickel, cobalt, and pesticides.

Manganese is everywhere – in soils, rivers, oceans, and lakes – and its oxidation depends upon the solid with which it interacts. How is this interaction different at the nanoscale? So far, Madden has found that nanoparticles are 30 times more efficient at promoting the manganese oxidation reaction than the same material in bulk.

One consequence of the research is the questioning of a long-held assumption about manganese oxidation – that the process requires bacteria because it is much slower in the absence of bacteria. But maybe it is particle size and not bacteria that influences the speed of the process in some environments.

"Reactivity is controlled by the electrons and electronic structure of the particles, which changes as the particle gets smaller," Madden explains. In a smaller hunk of matter, more of the atoms are at the surface. In the research circumstances, the iron oxide gave up electrons to the manganese, making them more susceptible to reaction with dissolved oxygen.

Madden says he can’t say yet what might happen as a result of such interactions. "We expect to synthesize smaller particles and see an even more efficient reaction."

Madden will present the paper, "Testing geochemical reactivity as a function of mineral size: Manganese oxidation promoted by hematite nanoparticles (GEOC 92)" at 5:30 p.m. Tuesday, March 30, at the Marriott -- Marquis NW as the last presentation of the symposium on Interfacial Phenomena: Linking Atomistic and Macroscopic Properties, Co-author is Virginia Tech professor of geosciences Michael F. Hochella Jr.

Madden is a member of the Hochella NanoGeoscience and mineral-microbe research group. He became a Ph.D. candidate in geosciences in fall 2000 and was awarded a National Science Foundation fellowship in 2001. His undergraduate degree is from Michigan State University, and he worked at Dart Oil and Gas in Mason, Mich., while at MSU.

Susan Trulove | EurekAlert!
Further information:
http://www.technews.vt.edu/

More articles from Earth Sciences:

nachricht Impacts of mass coral die-off on Indian Ocean reefs revealed
21.02.2017 | University of Exeter

nachricht How much biomass grows in the savannah?
16.02.2017 | Friedrich-Schiller-Universität Jena

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

NASA's fermi finds possible dark matter ties in andromeda galaxy

22.02.2017 | Physics and Astronomy

Wintering ducks connect isolated wetlands by dispersing plant seeds

22.02.2017 | Life Sciences

Impacts of mass coral die-off on Indian Ocean reefs revealed

21.02.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>