Water Pollution and Nanotechnology
How can nanotechnology be used to
reduce water pollution?
Nanotechnology is being used to develop solutions to three very different
problems in water quality.
challenge is the removal of industrial water pollution, such as a cleaning solvent called
TCE, from ground water. Nanoparticles can be used to convert the contaminating
chemical through a chemical reaction to make it harmless. Studies have shown
that this method can be used successfully to reach contaminates dispersed in
underground ponds and at much lower cost than methods which require pumping the
water out of the ground for treatment.
Another challenge is the removal of salt or metals from water. A
deionization method using electrodes composed of nano-sized fibers shows promise
for reducing the cost and energy requirements of turning salt water into
The third problem concerns the fact that standard filters do not work on
virus cells. A filter only a few nanometers in diameter is currently being
developed that should be capable of removing virus cells from water.
See the following section for more about the potential of nanotechnology in
removing contaminates from water.
Water Pollution: Nanotechnology Applications under Development
Researchers at EPFL have demonstrated a
solar powered water filter that uses titanium dioxide (TiO2) nanowires and carbon nanotubes
to purify water.
Researchers at Brown University have demonstrated how to create water filters
using short channels between graphene sheets
that can allow water to pass but blocks larger contaminates.
Researchers at Northwestern University have developed a
nanocomposite coating that can be applied to a
sponge causing the sponge to absorb oil, but not absorb water.
Researchers at Nagoya University have demonstrated the
use of nanocarbons modified with amino groups to remove heavy metal ions from water.
Researchers at the RMIT University and University of New South Wales have
demonstrated a filter made with nano-thin sheets of aluminium oxide
which can filter both heavy metals and oils from water.
Using nanoscavengers, in which a
layer of reactive nanoparticles coat a synthetic core which is designed to be
easily magnetized. The nanoparticles, for example silver nanoparticles if
bacteria is a problem, attach to or kill the pollutants. Then when a magnetic
field is applied the nanoscavengers are removed from the water.
Using pellets containing nanostructured
palladium and gold as a catalyst to
breakdown chlorinated compounds contaminating groundwater. Since palladium is
very expensive the researchers formed the pellets of nanoparticles that allow
almost every atom of palladium to react with the chlorinated compounds, reducing
the cost of the treatment.
micromotors to remove carbon dioxide from water.
Researchers at the University of Cincinnati have demonstrated a method
of removing antibiotics contaminating waterways. The method uses
nanoparticles that absorb antibiotics.
Using graphene oxide to remove radioactive material from water. Researchers
found that flakes of
graphene oxide absorbs radioactive ions in water. The graphene oxide then
forms clumps that can be removed from the water for disposal.
Using graphene as a membrane for low cost water desalination.
Researchers have determined that
graphene with holes the size
of a nanometer or less can be used to remove ions from water. They
believe this can be used to desalinate sea water at a lower cost than
the reverse osmosis techniques currently in use.
Using carbon nanotubes as the pores in reverse osmosis membranes. This can
decrease the power needed to run reverse osmosis desalination plants because
water molecules pass through carbon
nanotubes more easily than through other types of pores. Other researchers
are using carbon nanotubes to develope
water purification devices needed in developing countries.
Also carbon nanotubes are being developed to clean up oil spills. Researchers have found that adding boron atoms during the growth of carbon nanotubes causes the
nanotubes to grow in a sponge like material that can absorb many times it's weight in oil.
Using hair like nanoparticles (nano-hair) to
trap and measure the level of mercury
pollution in water.
Combining a nanomembrane with solar power to reduce the cost of desalinating seawater
iron nanoparticles to clean up carbon tetrachloride pollution in ground water
Adding graphene oxide to sand filters
to enhance their ability to remove pollutants from water.
Using silver chloride nanowires as a
photocatalysis to decompose organic molecules in polluted water.
Using an electrified filter composed of silver nanowires, carbon nanotubes and
cotton to kill bacteria in water.
Nanoparticles that can absorb radioactive particles polluting ground-water
iron nanoparticles allow them to neutralize dense, hydrophobic solvents
nanowire mats to absorb oil spills
Using iron oxide
nanoparticles to clean arsenic from water wells.
gold tipped carbon nanotubes to trap oil drops polluting water.
Using antimicrobial nanofibers and activated carbon in a
disposable filter as an inexpensive way to clean contaminated water.
Researchers at Pacific Northwestern Laboratory have developed a material to remove mercury from groundwater. The material is called
SAMMS, which is short for Self-Assembled Monolayers on Mesoporous Supports. This translates taking a ceramic particle whose surface has many nano-size pores and lining the nanopores with molecules that have sulfur atoms on one end, leaving a hole in the center that is lined with sulfur atoms as shown in figure-SAMMS. They line the nanopores with molecules containing sulfur because it bonds to mercury, so mercury atoms bond to the sulfur and are trapped in the nanopores.
Nanotechnology Company Directory
||Iron nanoparticles to treat groundwater pollutants
Campbell Applied Physics
||Also working on Capacitive Deionization using
||Nanotechnology enhanced membranes for water desalination
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