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8/12/2019 NBT Lecture 30
1/17
NANOTECHNOLOGY APPLICATIONS
MBT 413 Nano Biotechnology Lecture 30
8/12/2019 NBT Lecture 30
2/17
MBT 413 Nano Biotechnology Lecture 30
Applications of nanotechnology in environment
Nanotechnology and water treatment
treatment and remediation
nanotechnology has the potential to contribute to long-term water quality,availability, and viability of water resources, such as through the use of
advanced filtration materials that enable greater water reuse, recycling,
and desalinization
sensing and detection
development of new and enhanced sensors to detect biological and
chemical contaminants at very low concentration levels in the
environment, including water
pollution prevention
8/12/2019 NBT Lecture 30
3/17
MBT 413 Nano Biotechnology Lecture 30
Applications of nanotechnology in environment
884 million people lack access to safe water supplies
approximately one in eight people
6 kilometres is the average distance African and Asian
women walk to fetch water
3.6 million people die each year from water-related
diseases
98 per cent of water-related deaths occur in the developing
world
84 per cent of water-related deaths are in children ages 0
14
43 per cent of water-related deaths are due to diarrhoea
65 million People are at risk of arsenic poisoning in the
Bangladesh, India and Nepal area
8/12/2019 NBT Lecture 30
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MBT 413 Nano Biotechnology Lecture 30
Applications of nanotechnology in environment
Treatment and remediation
Nanotechnology
novel and effective in situ treatment technologies for groundwater
contaminant source zones
creation of novel nanoparticles with unique and tunable physical and
chemical properties
Their properties can be adjusted to make them highly reactive withcommon organic pollutants, and to minimize the formation of unwanted
toxic by-products.
8/12/2019 NBT Lecture 30
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MBT 413 Nano Biotechnology Lecture 30
Applications of nanotechnology in environment
Nano-based products relevant to developing countries seeking to
improve water supplies
Product How it works Importance Developer
Nanosponge for rainwater
harvesting
A combination of polymers
and glass nanoparticles that
can be printed onto
surfaces like fabrics to soak
up water
Rainwater harvesting is
increasingly important to
countries like China, Nepal
and Thailand. The
nanosponge is much more
efficient than traditional mist-
catching nets
Massachusetts
Institute of
Technology, United
States
Nanorust to remove arsenic Magnetic nanoparticles of
iron oxide suspended in
water bind arsenic, which is
then removed with a
magnet
India, Bangladesh and other
developing countries suffer
thousands of cases of arsenic
poisoning each year, linked to
poisoned wells
Rice University,
United States
Desalination membrane A combination of polymers
and nanoparticles that
draws in water ions and
repels dissolved salts
Already on the market, this
membrane enables
desalination with lower energy
costs than reverse osmosis
University of
California, Los
Angeles and
NanoH2O
http://web.mit.edu/http://web.mit.edu/http://web.mit.edu/http://media.rice.edu/media/NewsBot.asp?MODE=VIEW&ID=9032http://newsroom.ucla.edu/portal/ucla/Today-s-Seawater-Is-Tomorrow-s-7410.aspx?RelNum=7410http://newsroom.ucla.edu/portal/ucla/Today-s-Seawater-Is-Tomorrow-s-7410.aspx?RelNum=7410http://newsroom.ucla.edu/portal/ucla/Today-s-Seawater-Is-Tomorrow-s-7410.aspx?RelNum=7410http://newsroom.ucla.edu/portal/ucla/Today-s-Seawater-Is-Tomorrow-s-7410.aspx?RelNum=7410http://newsroom.ucla.edu/portal/ucla/Today-s-Seawater-Is-Tomorrow-s-7410.aspx?RelNum=7410http://newsroom.ucla.edu/portal/ucla/Today-s-Seawater-Is-Tomorrow-s-7410.aspx?RelNum=7410http://media.rice.edu/media/NewsBot.asp?MODE=VIEW&ID=9032http://web.mit.edu/http://web.mit.edu/http://web.mit.edu/8/12/2019 NBT Lecture 30
6/17
MBT 413 Nano Biotechnology Lecture 30
Applications of nanotechnology in environment
Nano-based products relevant to developing countries seeking to
improve water suppliesNanofiltration membrane Membrane made up of
polymers with a pore size
ranging from 0.1 to 10nm
Field tested to treat drinking
water in China and desalinate
water in Iran, using this
membrane requires less
energy than reverse osmosis
Saehan Industries,
Korea
Nanomesh waterstick A straw-like filtration device
that uses carbon nanotubes
placed on a flexible, porous,
material
The waterstick cleans as you
drink. Doctors in Africa are
using a prototype and the final
product will be made available
at an affordable cost in
developing countries
Seldon
Laboratories,
United States
World filter Filter using a nanofibre
layer, made up of polymers,resins, ceramic and other
materials, that removes
contaminants
Designed specifically for
household or community-leveluse in developing countries.
The filters are effective, easy
to use and require no
maintenance
KX Industries,
United States
Pesticide filter Filter using nanosilver to
adsorb and then degrade
three pesticides commonly
found in Indian watersupplies
Pesticides are often found in
developing country water
supplies. This pesticide filter
could provide a typical Indianhousehold with 6000 litres of
clean water over one year
Indian Institute of
Technology in
Chennai, India, and
Eureka ForbesLimited, India
http://www.saehan.com/http://www.seldontechnologies.com/http://www.seldontechnologies.com/http://www.iitm.ac.in/http://www.iitm.ac.in/http://www.iitm.ac.in/http://www.eurekaforbes.com/http://www.eurekaforbes.com/http://www.eurekaforbes.com/http://www.eurekaforbes.com/http://www.iitm.ac.in/http://www.iitm.ac.in/http://www.iitm.ac.in/http://www.seldontechnologies.com/http://www.seldontechnologies.com/http://www.saehan.com/8/12/2019 NBT Lecture 30
7/17
MBT 413 Nano Biotechnology Lecture 30
Applications of nanotechnology in environment
Highly reactive nanoparticles such as-
1.nanoscale zerovalent iron (nanoiron or NZVI)
2.nanocatalysts (e.g., Au/Pd bimetallic nanoparticles
3.nanosized sorbents
to remediate contamination by organic and inorganic contaminants.
their small size (10500 nm) also provides an opportunity to deliver these
remedial agents to subsurface contaminants in situ, and provides access
to contamination trapped in the smallest pores in an aquifer matrix.
The high reactivity, and the potential for facile delivery directly to the
contaminant source, suggests that nanoparticles can accelerate the
degradation rate of contaminants in the source zone, and decrease the
time and cost of remediation relative to traditional treatment technologies
that address the plume.
8/12/2019 NBT Lecture 30
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MBT 413 Nano Biotechnology Lecture 30
Applications of nanotechnology in environment
Nanoscale zerovalent iron and bimetallics (e.g., Fe0/Pd)
for the rapidin situ degradation of chlorinated organic compounds and
reduction of heavy metals in contaminant source zones
Nanoparticles can sequester groundwater contaminants (via adsorption
or complexation), making them immobile, or can degrade or transform
them to innocuous compounds.
8/12/2019 NBT Lecture 30
9/17
MBT 413 Nano Biotechnology Lecture 30
Applications of nanotechnology in environment
Reactive nanoparticles
TCE dechlorination by nanoiron.
Fe0 oxidation provides electrons
for the reduction of TCE. The Fe0 coreshrinks while the Fe3O4 oxide shell
grows. The particles are no longer
active once all of the Fe0 is oxidized.
Contaminant transformations by nanoiron, which is a strong reductant,
are typically redox reactions. When the oxidant or reductant is the
nanoparticle itself, it is considered a reactive nanoparticle.
8/12/2019 NBT Lecture 30
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MBT 413 Nano Biotechnology Lecture 30
Applications of nanotechnology in environment
Catalytic nanoparticles
Nanoparticles that catalyze redox reactions but are not themselves
transformed are catalytic nanoparticles, which requires an additional
reagent that serves as the reductant or oxidante.g., Pd nanoparticles require H2 as a reductant
TCE dechlorination by catalytic Pd
particles. H2 is supplied as the
reductant for TCE dechlorination. In
principle, the Pd catalyst is not altered
by the reaction and can remain active
as long as H2 is supplied. In practice,
catalyst deactivation occurs and the
particle lifetime is finite. Catalyst
regeneration may extend the life of thearticle.
8/12/2019 NBT Lecture 30
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MBT 413 Nano Biotechnology Lecture 30
Applications of nanotechnology in environment
Adsorbent nanoparticlesSome nanomaterials are engineered to strongly sequester contaminants.
The high affinity for the contaminant allows the nanoparticle to significantly
lower the aqueous phase concentrationsand serves to concentrate the
contaminants onto the particles.
Once concentrated onto the nanoparticles, the contaminants can be
removed along with the nanoparticles. This can be highly effective for
hydrophobic organic contaminants such as PCBs (polychlorinated
biphenyls) and PAHs(polyaromatic hydrocarbon) and for heavy metals.
8/12/2019 NBT Lecture 30
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MBT 413 Nano Biotechnology Lecture 30
Applications of nanotechnology in environment
Factors affecting in si turemediation
remediation with any type of nanoparticle, it is important to know which
groundwater contaminants will respond to the treatment and which will
not.
It is also important to know how long the reactive or catalytic particles
will remain active as this will determine important operation decisions
such as how much to inject and when reinjection may be necessary.
8/12/2019 NBT Lecture 30
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MBT 413 Nano Biotechnology Lecture 30
Applications of nanotechnology in environment
Reduction of chlorinated organic compounds (COC) or heavy metals
using Fe nanoparticles
Degradation of halogenated hydrocarbons, particularly chlorinated
solvents,occurs via a reductive process.
The Fe0 in the nanoiron is oxidized by the chlorinated solvent, which is
subsequently reduced. For chlorinated hydrocarbons, the reduction
typically results in the replacement of a chlorine atom with a hydrogen
atom.
For heavy metals, the metal, such as Pb(II) or Cr(VI), is reduced to its
zerovalent form on the nanoiron surface, or forms mixed (Fe-Metal)
precipitates that are highly insoluble.
8/12/2019 NBT Lecture 30
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MBT 413 Nano Biotechnology Lecture 30
Applications of nanotechnology in environment
general half-reactions for the oxidation of iron and the reduction of
chlorinated organic compounds (COC) or heavy metals are given in Eqs.
1 to 3, where Me is a metal ion of charge a.
8/12/2019 NBT Lecture 30
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MBT 413 Nano Biotechnology Lecture 30
Applications of nanotechnology in environment
In the case of nanoiron, or Fe0-based bimetallics, the reduction of the
contaminant is surface-mediated, and the particle itself is the reductant.
nanoiron particles have a high surface to-volume ratio and therefore have
high reactivity with the target contaminants.
The following generalizations can be made about the reactivity and
lifetime of all nanoparticulate remedial agents that are themselves the
reactive
Any process that affects the surface properties of the particles (e.g.,formation of an Fe-oxide on the surface) can affect theirreactivity.
8/12/2019 NBT Lecture 30
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MBT 413 Nano Biotechnology Lecture 30
Applications of nanotechnology in environment
Any oxidant (e.g., O2 or NO3 ) competing with the target contaminant
will utilize electrons and may lower the rate and efficiency of the nanoiron
treatment for the target contaminants.
Reactive nanoparticles that serve as a reactant rather than a catalyst
will have a finite lifetime, the length of which depends on theconcentration of the target contaminant, the presence of competing
oxidants, and the selectivity of the particles for the desired reaction.
8/12/2019 NBT Lecture 30
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MBT 413 Nano Biotechnology Lecture 30
Applications of nanotechnology in environment
Fe3O4 magnetic nanoparticles with humic acid can 1) greatly enhance the
stability of dispersed nanoparticles by preventing their aggregation; 2)
maintain the saturation magnetization by avoiding their oxidation; and 3)
enlarge the adsorption capacity for some heavy metals by making use of
the abundant carboxylic acid and phenolic hydroxyl functional groups of
humic acid to complex with heavy metal ions.