Judges’ Queries and Presenter’s Replies

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Presentation Discussion

  • May 23, 2012 | 12:25 p.m.

    Nice work on an important topic.
    It would seem that the use of silver in textiles has probably the most environmental impact compared with other uses.
    Since silver is quite reactive (unlike other nobel metals) do the nanoparticles dissolve away into silver compounds so that the nanocharacter is not retained?

  • Icon for: Amy Dale

    Amy Dale

    May 23, 2012 | 01:34 p.m.

    Great question!
    It’s hard to know for certain if silver-imbued textiles are the biggest culprit, since we really do not have much data on nanosilver production. The PEN (Project on Emerging Nanotechnologies) database suggests textiles are a major player, but nanosilver is also found in cosmetics and is used for a wide range of antibacterial applications. The PEN database also appears to favor consumer products over other applications of nanomaterials, so the data set may not be entirely representative.
    It’s true that silver is soluble, and that nanosilver is especially so. However, in natural waters and sediments (and especially in sulfur-rich environments like sewage treatment plants), the silver ions released when nanosilver dissolves tend to undergo a precipitation reaction on the surface of the particle, creating a coat of silver sulfide. Silver sulfide is extremely insoluble in water and slows further dissolution of the particle considerably.
    The nanosilver therefore retains its particulate character rather than dissolving away (though over long time scales it will eventually dissolve away). However, the “nano” property of nanosilver that we exploit by shrinking it is its enhanced ability to dissolve (a result of increasing the specific surface area of the particle). In that sense, I would say nanosilver does not retain its nano character in the environment.

  • Icon for: Carol Johnson

    Carol Johnson

    May 24, 2012 | 11:54 a.m.

    Glad to see CEINT represented! :)

  • Further posting is closed as the competition has ended.

  1. Amy Dale
  2. http://www.igert.org/profiles/4221
  3. Graduate Student
  4. Presenter’s IGERT
  5. Carnegie Mellon University
  1. John Stegemeier
  2. http://www.igert.org/profiles/4772
  3. Graduate Student
  4. Presenter’s IGERT
  5. Carnegie Mellon University

Engineering at the Interface: Integrating Laboratory Research and Modeling to Assess Nanosilver Risk

The global market for nanotechnology is estimated to have reached $15.7 billion in 2010 and is expected to grow to approximately $26.7 billion by 2015. Nanosilver, which is used as an additive in many products (e.g., plastics, textiles) because of its antibacterial properties, is the most widely advertised nanomaterial in consumer goods. Understanding the fate and transport of nanosilver is environmentally important because nanosilver and the silver ion released during dissolution are known to be toxic to a wide range of aquatic invertebrates, fish, and estuarine organisms. As recipients of the Nanotechnology, Environmental Effects, and Policy (NEEP) Integrative Graduate Education and Research Training (IGERT) fellowship, we work at the interface of environmental science and risk assessment in order to advance the understanding of nanoparticle movement in the environment, nanoparticle interactions with organisms, the mechanisms by which nanoparticles exert their influence, and their potential environmental impacts. Our goal with this project is to develop a model describing how nanosilver is transported and transforms once released to the environment. This cross-disciplinary work integrates laboratory research on the behavior of nanosilver and transformed silver species in the environment with a computational/mathematical approach to modeling and risk forecasting. Our preliminary work highlights the value of developing the model as part of a larger risk assessment framework. Using this approach, we hope to advance not only our knowledge of nanoparticles in the environment but also our understanding of how best to avoid their potential negative consequences.