Presentation on

Water Pollution and

Nanotechnology

Presented by

Aruna Ashok Kumar

Ashwini Kumar Deva lal bairwa

How can nanotechnology be used to reduce water pollution?

• The removal of industrial water pollution, such as a cleaning solvent called TCE (trichloroethene) , from ground water. Nanoparticles can be used to convert the contaminating chemical through a chemical reaction to make it harmless.

• To reach contaminates dispersed in underground ponds at much lower cost than other methods

• 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 drinking water.

• 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.

NANO-TECHNOLOGIES FOR ENVIRONMENT

CLEAN UP

1. IRON NANO PARTICALS

• "The use of nano-sized particles of iron for cleaning up contaminants in groundwater, soil and sediments is one of the hottest new technologies to emerge in recent years.

Nano iron particle clusters viewed by transmission electron microscopy

• Two leading types of nanoparticle-sized iron that are being promoted by others for groundwater remediation.

• They measured how fast these particles degrade carbon tetrachloride and they determined the major projects of the reaction.

• Carbon tetrachloride is a manufactured chemical used mainly in cleaning fluids and degreasing agents.

• In a few locations, spills of these liquids infiltrated the soil and created very large areas of contaminated groundwater and soil.

• Carbon tetrachloride is a toxic chemical that has been shown to cause cancer in animals.

• One of the nano-irons studied, a commercially available product of iron oxide with a magnetite shell high in sulfur, quickly and effectively degraded carbon tetrachloride to a mixture of relatively harmless products.

• This was an exciting find because it may provide the basis for effective remediation of real field sites with groundwater that is contaminated with carbon tetrachloride.

• The other nano-iron studied has a shell, or coating, high in oxidized boron. While the oxide-coated iron also rapidly degraded the carbon tetrachloride.

2. NANO BATONS

• New technologies for cleaning up oil spills and polluted groundwater.

• To encase oil drops. • For delivering drugs. • Tiny & stick-shaped particles of

metal and carbon can trap oil droplets in water by spontaneously assembling into bag-like sacs.

• The tiny particles were found to assemble spontaneously by the tens of millions into spherical sacs as large as pellets around droplets of oil in water.

• In addition,UV light and magnetic fields could be used to flip the nanoparticles.

FABRICATION OF NANO-BATONS

The multisegmented nanowires were made by connecting two nanomaterials with different properties, much like an eraser is attached to the end of a wooden pencil.

1. With carbon nanotubes -hollow tubes of pure carbon. Atop the nanotubes, they added short segments of gold. by adding various other segments like sections of nickel or other materials can create truly multifunctional nanostructures.

PRINCIPLE

• The tendency of these nanobatons to assemble in water-oil mixtures derives from basic chemistry.

• The gold end of the wire is water-loving, or hydrophilic, while the carbon end is water-averse, or hydrophobic.

• The thin, water-tight sacs that surround all living cells are formed by interlocking arrangements of hydrophilic and hydrophobic chemicals, and the sac-like structures created in the study are very similar.

• For oil droplets suspended in water, the spheres give off a light yellow color because of the exposed gold ends.

• With water droplets, we observe a dark sphere due to the protruding black nanotubes.

3. SMART DUST

• "The core of the nanotechnology revolution lies in designing inorganic nanoparticles that can self-assemble into larger structures like a 'smart dust' that performs different functions in the world – for cleaning up pollution.

4.NANO WIRE PAPER

• The nanowire paper could also impact filtering and the purification of water,

• The membrane that can absorb up to 20 times its weight in oil, and can be recycled many times for future use. The oil itself can also be recovered.

• Made of potassium manganese oxide, the nanowires are stable at high temperatures. As a result, oil within a loaded membrane can be removed by heating above the boiling point of oil.

• The oil evaporates, and can be condensed back into a liquid. The membrane--and oil--can be used again.

FABRICATION

• The membrane is created by the same general technique as its low-tech cousin, paper & a suspension of nanowire, like a suspension of cellulose [the key component of paper], dry it on a non-sticking plate, and we get pretty much nanowire paper.

References