Water Pollution Prevention and Treatment using Nanotechnology

WATER POLLUTION PREVENTION AND

TREATMENT USING NANOTECHNOLOGY

By:Name : Kavaiya Ashish Rajeshkumar

Roll No:U10CH010

Guide : Dr.Z.V.P. Murthy

Chemical Engineering Department,Sardar Vallabhbhai National Institute of Technology, Surat-395007

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More than One Billion people In the World lack access to clean water, and

things are getting worse.

Nanotechnology encompasses a broad range of tools, techniques, and

applications and is widely perceived as one of the most significant

technologies of the 21st century.

Nanomaterials are manufactured materials with a structure between

approximately 1 nanometer (nm) and 100 nm.Their unique

physicochemical (e.g., size, shape) and surface (e.g., reactivity,

conductivity) properties contribute to the development of materials with

novel properties and technical solutions to problems that have been

challenging to solve with conventional technologies.

Introduction :

Today Availabilty of claen,abundant fresh water for human use is among the

most pressing issues in the world.

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Water purification using nanotechnology exploits nanoscopic materials

Fullerenes NanoParticles

Borosilicate glass nanoparticles.

Composed entirely of

Carbon.

Tube shaped

Bucky balls.

Nanotubes.

Carbon nanotubes.

Metallic, ceramic or inorganic.

Dimensions 1-100nm.

Large surface area, very reactive.

Exhibit interesting mechanical,

magnetic, optical, chemical

properties.

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Pollution Prevention by Nanotechnology

A reduction in the use of

Raw materials,

Water

other resources

The elimination or reduction of waste and on the other hand to more efficient use

of energy or involvement in energy production.

The implementation of green chemistry principles for the production of

nanoparticles and for nanotechnological applications in standard chemical

engineering will lead to a great reduction in waste generation, less hazardous

chemical syntheses, improved catalysis and finally an inherently safer

chemistry.

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Water Treatment

1. Nanofiltration

2. Catalytic Degradation of Water Pollutants.

3. Adsorption of Pollutants

4. Magnetic Nanoparticles

5. Nanosensors

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1.Nanofiltration:

NF membranes are pressure-driven membranes with properties between those

of reverse osmosis and ultrafiltration membranes and have pore sizes between 0.2

and 4 nm.

Nanof iltration membranes (NFmembranes) are used in water treatment for

drinking water production or wastewater treatment

NF membranes have been shown to remove turbidity, microorganisms and

inorganic ions such as Ca and Na.

They are used for softening of groundwater (reduction in water hardness), for

removal of dissolved organic matter and trace pollutants from surface water, for

wastewater treatment (removal of organic and inorganic pollutants and organic

carbon) and for pretreatment in seawater desalination.

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Seawater Desalination using Nanofiltration Method – The Long Beach Method

Seawater filtered to remove suspended solids.

Stage 1: Filtered seawater pumped under high pressure through nanofiltration membrane.Only smallest 12% of salt molecules pass through

Stage 2: Water from Stage 1 is pumped under lower pressure through second nanofiltrationMembrane. Blocks passage of almost all remaining salts.

High quality potable water produced.

Energy savings:

Traditional desalination method pressure required for pumping: 1000pounds per square inch(psi).

Long Beach Method: 525psi first stage, 250psi second stage.Energy savings: 20-30%

Pilot plant running from 2001.

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2. Catalytic Degradation of Water Pollutants

Nanoparticles serve as catalysts.

Chemically degrade pollutants.

Nano titanium-dioxide particles for degrading organic as well inorganic pollutants.

In water, photo-oxidation occurs primarily through hydroxyl radicals. Because

TiO2 requires ultraviolet light for excitation, it has been sensitized to visible

light by dyes, through incorporation of transition metal ions or by doping with

nitrogen .

Nanoscale zerovalent Fe0 & bimetallic Fe0 detoxify organic & inorganic

pollutants in aqueous solutions.

Nanoscale zerovalent iron (nZVI) can reduce not only organic contaminants but also the inorganic anions nitrate, which is reduced to ammonia, perchlorate (plus chlorate or chlorite), which is reduced to chloride, selenate, arsenate, arsenite and chromate .

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Soil and Groundwater Remediation by nZVI Granular ZVI in the form of reactive barriers has been used for many years at numerous sites all over the world for the remediation of organic and inorganic contaminants in groundwater .

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With nZVI, two possible techniques are used:

1. Immobile nZVI is injected to form a zone of iron particles adsorbed on the aquifer solids

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2. Mobile nZVI is injected to form a plume of reactive Fe particles that destroy any organic contaminants that dissolve from a DNAPL (dense non-aqueous phase liquid)source in the.

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Magnetic nanoparticles offer advantages over non-magnetic nanoparticles because they can easily be separated from water using a magnetic field.

Separation using magnetic gradients, the so-called high magnetic gradient separation (HGMS), is a process widely used in medicine and ore processing.

This technique allows one to design processes where the particles not only remove compounds from water but also can easily be removed again and then be recycled or regenerated.

This approach has been proposed with magnetite (Fe3O4), maghemite (g-Fe2O3) and jacobsite (MnFe2O4) nanoparticles for removal of chromium (VI) from wastewater.

Water-soluble CNTs have been functionalized with magnetic iron nanoparticles for removal of aromatic compounds from water and easy separation from water for re-use.

4. Magnetic Nanoparticles

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3. Adsorption of Pollutants

Sorbents are widely used in water treatment and purification to remove

organic and inorganic contaminants. Eg.activated carbon and ion-exchange

resins .

The unique structure and electronic properties of some nanoparticles can

make them especially powerful adsorbents

The removal of metals and other inorganic ions, mainly nanosized metal oxides but

also natural nanosized clays have been investigated

Chemically modified nanomaterials have also attracted a lot of attention,

especially nanoporous materials dues to their exceptionally high surface area.

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5. Nanosensors

Nanosensors are any biological, chemical, or surgical sensory points used to convey information about nanoparticles to the macroscopic world.

Nanosensors for the detection of contaminants and pathogens can improve health, maintain a safe food and water supply, and allow for the use of otherwise unusable water sources.

New sensor technology combined with micro- and nanofabrication technology is expected to lead to small, portable, and highly accurate sensors to detect chemical and biochemical parameters.

BioFinger is developing a handheld device that incorporates nano- and microcantilevers on a microchip.

The system could be used to analyze chemicals and bacteria in water.

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Product How it works Importance Developers

Nanorust to remove

arscenic

Magnetic

nanoparticles of iron

oxide suspended in

water bind arscenic,

which is then

removed with a

magnet

India, Bangladesh

and other developing

countries suffer

thousands of cases of

arscenic poisoning

each year, linked to

poisoning of wells.

Rice University,

United States.

Desalination

membrane

A combination of

polymers and

nanoparticles that

draws in water ions

and repels dissolved

salts.

Already in the

market, this

membrane enables

desalination with

lower energy costs

than reverse osmosis.

University of

California, Los

Angeles and

NanoH2O

PRODUCTS IN MARKET

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Product How it works Importance Developers

Nanofiltration

Membrane

Membrane made up of

polymers with a pore

size ranging from 0.1-

10nm

Field tested to treat

drinking water in China

and desalinate water in

Iran. Using this membrane

requires less enrgy than

reverse osmosis.

Sachen Industries,

Korea.

Nanomesh waterstick A straw like filtration

device that uses carbon

nanotubes plaed on a

flexible, porous

material.

The waterstick cleans the

water as it is drunk.

Doctors in Africa are using

a prototype and the final

product is said to be

available at an affordable

cost in developing

countries.

Seldon Laboratories

, United States.

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Product How it works Importance Developers

World Filter Filter using a

nanofibre layer, made

up of polymers,

resins, ceramics and

other materials that

remove contaminants.

Designed specifically for

the household or

community level use in

developing countries. The

filters are effective, easy to

use and require no

maintenance.

KX Industries, US

Pesticide Filter Filter using

nanosilver to adsorb

and then degrade

three pesticides

commonly found in

the Indian water

supplies.

Pesticides are often found in

the developing countries

water supply. This pesticide

filter can provide a typical

Indian household with 6000

liters of clean water in one

year.

Indian Institute of

Technology,

Chennai, India and

Eureka Forbes

Limited, India.

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CONCLUSION

Nanotechnology to water treatment devices appears to be driven by

several factors including, but not limited to,

Reduced costs,

Improved ability to selectively

Remove contaminants,

Durability, and size of device.

Proper studies are to be carried out to assess any harmful effects on environment and living beings.

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And Last…

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References :

[1] P. Gleick, The World's Water—The Biennial Report on Freshwater Resources , Pacifi c Institute, Oakland, California, 1998, p. 40.

[2] B. Nowack, “Pollution Prevention and Treatment Using Nanotechnology,” Environmental Aspects, ISBN: 978-3-527-31735-6, Date 15 JUL 2010

[3]T.Hillie, M.Munasinghe, M.Hlope, Y. Deraniyagala, “Nanotechnology,Water & Development,” http://www.merid.org/~/media/Files/Projects/nano-waterworkshop/NanoWaterPaperFinal.ashx ,July 2010

[4] S. C. Chang, P. Adriaens , “Nano-Immunodetection and Quantification of Mycobacteria in Metalworking Fluids,” Eng. Sci. 2007, 24, 58.

[5] N. Savage, M. Diallo, J. Duncan, A. Street, R. Sutich, Nanotechnology Applications for Clean Water, New York: William Andrew Inc.2009