to promote and coordinate interdisciplinary research and education

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to promote and coordinate interdisciplinary
research and education in the molecular and
nanosciences at Brown
Nanotechnology and the Environment Applications
and Implications
Robert Hurt, Brown University
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Nanotechnology
Defined as the systematic manipulation of matter
on the length scale 1 100 nm Includes a wide
range of technologies based on ultrafine
particles, fibers, and more complex arrangements
of matter Supported by the National
Nanotechnology Initiative 1 billion
US/yr Nanotechnology business sector includes
gt 250 US companies Over 450 consumer products
identified In recent survey
Nano-Silver In textiles
From the Woodrow Wilson Institute website
http//www.nanotechproject.org/news/archive/nanot
echnology_now_used_in_nearly/
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IMNI / Brown Partners
THEMES
Center for Advanced Materials Research Center
for Nanoscience and Soft Matter NanoHealth
Working Group
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Nanotechnology Implications
Small size - small aerodynamic diameter ? deep
lung penetration - high permeability in
biological membranes - enhanced cellular uptake
- specific interactions with DNA, proteins
High surface area - high surface activity -
facilitated transport the Trojan horse effect
Fibrous morphology - agglomeration and airway
blockage - difficulty with lung clearance
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Challenge the Diversity, Complexity, and
Evolving Nature of Nanomaterials
Equi-axed forms (nanoparticles) - fullerenes
(carbon) - metallic nanoparticles (e.g. Au, Fe,
Ni) - nanophase ceramics and polymers -
dendrimers - quantum dots (semiconductor
NPs) One-dimensional (fibrous) forms - carbon
nanotubes - nanofibers (carbon, polymer,
ceramic) - nanowires (usually metals) -
nanorods (any chemistry, modest L/D)
Two-dimensional (lamellar) forms Nanoplatelet
graphite, clay, graphene Nanostructured
surfaces Nanostructured solids
Carbon nanoparticles
Fe/silica core/shell Sun, Nurmikko
Single-wall nanotube bundle, Thess 1996
Nanofiber-cell interaction
From T.J. Webster
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The Brown Approach to Green Nanomaterials
Nanotechnology
Biology
Point of contact between nanomaterial / living
receptor
Surface modification
DNA damage
Persistent inflammation
Consumer use, disposal
Environmental science
Purification
Membrane damage
Bioaccumulation
Synthesis
Environmental fate. transport,
transformation and exposure
Cellular uptake
Deposition
Translocation metabolism excretion
ROS production
Formulation (surfactants, solvents, imbedding
matrices)
Epigenetic effects
What material feature(s) triggers the biological
response?
Processing stresses
Developmental effects
RD Technical decision-making
Causes gt Effects
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Nanotechnology and the Environment Applications

• Nanomaterials are
• Sorbents for pollutant capture (based on
  elevated surface area)
• Catalysts for pollutant destruction
• (e.g. zero-valent iron for ground water
  treatment)
• Anti-bacterial agents (e.g. nano-silver)
• Components in alternative energy technologies
  (fuel cells, batteries etc)

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Example application Mercury capture from
fluorescent lamps

• Most fluorescent lamps contain 3 10 mg of Hg

• The new compact fluorescent lamps (CFLs) contain
• 3 5 mg Hg
• Recent federal legislation will phase out
  incandescents
• by 2012. 98 of CFLs are not currently
  recycled.
• Limited information available on the
• behavior of this Hg upon lamp breakage

A modern CFL
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- Mercury poisoning was once common, but has
become rare since 1960s
- One modern case of Hg poisoning by broken
fluorescent lamps Tunnessen, 1987.
- Unborn and growing children are most susceptible
Vapor exposure limits OSHA, 8 hr workday
100 ug/m3 American Conference of Gov. and
Ind. Hygienist, 8 hr wkday 25 ug/m3 ATSDR
for continual habitation by children 0.2 ug/m3
Analysis from our release data 1 broken CFL
emits gt 1 mg Hg in a 500 m3 room ? gt 2.0 ug/m3
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Can we manage Hg in CFLs to 1. reduce direct
human exposure (accidental breakage) ? 2.
environmental release (at end of lamp life)?
Powders or cloth-impregnated sorbents to treat
spill sites
Sorbent-lined disposal bags / recycle boxes --
react and stabilize Hg vapor to prevent
release in landfill or during recycling
Challenge low activity of many sorbents at room
temperature
Approach use new nanosynthesis methods to
enhance kinetics and capacity
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Comparison of sulfur nanotubes and commercial
powdered sulfur demonstrate the advantages of
nano-synthesis
Sulfur nanotubes
Commercial powdered sulfur
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Demonstration of In Situ Hg Capture with
Nanomaterials
CFL mercury release after containment with
sorbent in simulated disposal bag
With nanomaterial X (10 mg)
Free release (no sorbent)
With activated carbon (1 g)
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Financial support from the EPA, NSF, and NIEHS
is gratefully acknowledged
UPCOMING EVENT! IMNI Nanoscience
Forum Three days / three symposia - Monday
May 5 Advanced Materials - Tuesday May 6
Nanoscience - Wednesday, May 7
NanoHealth with distinguished guests from
academia, government, industry