28-04-2011, 10:55 AM
PRESENTED BY:
K.M.HUNDEKAR
[attachment=12985]
NANOTECHNOLOGY FOR WATER TREATMENT
> Deals with manufacturing or manipulation of materials at nanoscale(10-9m). > Has applications in many different fields, like electronics, medical, energy sector, environmental remediation. > Being evaluated in water treatment processes in recent years > Materials having nanoscale dimensions referred to as Nanomaterials.
FULLERENES
NANOPARTICLES
NANOMATERIALS IN WATER TREATMENT SYSTEMS
Nanofilters:
Made of carbon nanotubes.
Pore size: 0.0001-0.001μm.
Can remove virus, bacteria, suspended solids, large multivalent ions, dissolved organics, herbiscides, pesticides etc.
Greater efficiency compared to microfilters and ultrafilters.
Energy usage – Low.
Operating cost – Rs. 10-20 per 1000 liters.[2]
Useful in desalination operations. Being used for desalination in Israel & certain U.S. Municipalities notably Long Beach, California Municipal Water District.[1]
Seawater Desalination – The Long Beach Method[4]
2.Nanosorbents:
Used majorly in water remediation. For removing inorganic and organic pollutants, from contaminated water.
Nanoparticles used as sorbents.
Nanoparticles can be functionalized with various chemical groups to increase their affinity towards target compounds.
Nanocrystalline zeolites can remediate water containing cationic species such as ammonium and heavy metals. As well chemicals like 137Cs and 90Sr. [5].
Magnetic nanoparticles bind with contaminants , such as oil and arsenic and removed using a magnet.
3. Nanocatalysts & redox active nanoparticles:
Nanoparticles serve as catalysts.
Chemically degrade pollutants.
Scientists from IISc, Bangalore-India are evaluating immobilized nano titanium-dioxide particles for degrading organic as well inorganic pollutants.
Nanoscale zerovalent Fe0 & bimetallic Fe0 detoxify organic & inorganic pollutants in aqueous solutions.
Fe0, Fe0/Pt0, Fe0/Pd0, Fe0/Ag0, Fe0/Ni0, Fe0/Co0 can reduce chlorinated alkanes, alkenes, chlorinated benzenes, pesticides, organic dyes, nitro aromatics, nitrates to less toxic and recalcitrant byproducts.[7]
4.Bioactive nanoparticles:
Being evaluated to decrease use of chemical reagents used for disinfection.
MgO nanoparticles effective against Gram-positive and Gram-negative bacteria.
Silver nanoparticles found effective against both Gram positive and negative. Especially, Staphylococcus aureus, E.coli, Klebsiella pneumoniae and Pseudomonas aeruginosa.
Two products in India utilizing Bioactive nanoparticles
PRODUCTS IN MARKET
Risks , challenges and opportunities
Potential health and environmental risks.
Integration of nanomaterials into existing water purification systems.
Availability and cost.
CONCLUSION
Already showing promising results.
Once certain impending hurdles are overcome, will define the modern water purification systems.
Proper studies are to be carried out to assess any harmful effects on environment and living beings.
K.M.HUNDEKAR
[attachment=12985]
NANOTECHNOLOGY FOR WATER TREATMENT
> Deals with manufacturing or manipulation of materials at nanoscale(10-9m). > Has applications in many different fields, like electronics, medical, energy sector, environmental remediation. > Being evaluated in water treatment processes in recent years > Materials having nanoscale dimensions referred to as Nanomaterials.
FULLERENES
NANOPARTICLES
NANOMATERIALS IN WATER TREATMENT SYSTEMS
Nanofilters:
Made of carbon nanotubes.
Pore size: 0.0001-0.001μm.
Can remove virus, bacteria, suspended solids, large multivalent ions, dissolved organics, herbiscides, pesticides etc.
Greater efficiency compared to microfilters and ultrafilters.
Energy usage – Low.
Operating cost – Rs. 10-20 per 1000 liters.[2]
Useful in desalination operations. Being used for desalination in Israel & certain U.S. Municipalities notably Long Beach, California Municipal Water District.[1]
Seawater Desalination – The Long Beach Method[4]
2.Nanosorbents:
Used majorly in water remediation. For removing inorganic and organic pollutants, from contaminated water.
Nanoparticles used as sorbents.
Nanoparticles can be functionalized with various chemical groups to increase their affinity towards target compounds.
Nanocrystalline zeolites can remediate water containing cationic species such as ammonium and heavy metals. As well chemicals like 137Cs and 90Sr. [5].
Magnetic nanoparticles bind with contaminants , such as oil and arsenic and removed using a magnet.
3. Nanocatalysts & redox active nanoparticles:
Nanoparticles serve as catalysts.
Chemically degrade pollutants.
Scientists from IISc, Bangalore-India are evaluating immobilized nano titanium-dioxide particles for degrading organic as well inorganic pollutants.
Nanoscale zerovalent Fe0 & bimetallic Fe0 detoxify organic & inorganic pollutants in aqueous solutions.
Fe0, Fe0/Pt0, Fe0/Pd0, Fe0/Ag0, Fe0/Ni0, Fe0/Co0 can reduce chlorinated alkanes, alkenes, chlorinated benzenes, pesticides, organic dyes, nitro aromatics, nitrates to less toxic and recalcitrant byproducts.[7]
4.Bioactive nanoparticles:
Being evaluated to decrease use of chemical reagents used for disinfection.
MgO nanoparticles effective against Gram-positive and Gram-negative bacteria.
Silver nanoparticles found effective against both Gram positive and negative. Especially, Staphylococcus aureus, E.coli, Klebsiella pneumoniae and Pseudomonas aeruginosa.
Two products in India utilizing Bioactive nanoparticles
PRODUCTS IN MARKET
Risks , challenges and opportunities
Potential health and environmental risks.
Integration of nanomaterials into existing water purification systems.
Availability and cost.
CONCLUSION
Already showing promising results.
Once certain impending hurdles are overcome, will define the modern water purification systems.
Proper studies are to be carried out to assess any harmful effects on environment and living beings.
