nanotechnology in waste water treatment
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NANOTECHNOLOGY IN WASTEWATER TREATMENT
Presented by , Guided by, ANOOPA ANN THOMAS Dr .MARY LUBI C GCANECH010
WATER, WATER EVERY WHERE BUT NOT A DROP TO DRINK!
Over 75% of the earth surface is covered in water 97.5% of this water is salt water, leaving 2.5% as fresh water.
Nearly 70% of the fresh water is frozen in the icecaps of
Antartica and Greenland; most of the remainder is present as soil
moisture or as groundwater not accessible to human use.
Less than 1% of the world’s freshwater is accessible for direct
human uses.
WHAT WE NEED?????
Fresh water
SECTOR/PROCESS
Wastewater
Why wastewater treatment??? Increasing population
Depleting water resources
Climate change resulting in prolonged droughts and floods.
CONVENTIONAL WASTEWATER TREATMENT METHODS
Coagulation
Chlorination
Flocculation
Lime softening
Ozonation
Membrane separation processes
etc....
Why research is still going on?????
Day to day Change in wastewater composition
Requirement of stable methods
Requirement of economical methods
Requirement of effective methods
Search for reliable methods
UNSOLVED TECHNOLOGY PROBLEMS......
Mercury contamination, Minamata, Japan, 1956
Microbial contamination, Zimbabwe, 2009
Pesticide contamination, Kerala, 2001
Fluoride contamination, India, 2003
What is nanotechnology??
The creation of functional materials ,devices and systems
through control of matter on the nanometer length scale (1-
100nm), and exploitation of novel phenomenon and properties
(physical, chemical and biological ) at that length scale.
NANOPARTICLES IN WASTEWATER TREATMENT
Dendrimers
Metal nanoparticles
Zeolites
Carbonaceous nanomaterials
Dendrimers
Size → 1-20 nm
Globular shape
Structure → 3 regions
Dendrimers differs in structure
Presence of interior voids
Eg: PAMAM (Polyamidoamine) dendrimers
Ethylene Diamine (EDA) core and terminal NH2 groups
can recover Cu ( II ) ions from aqueous solutions.
Cu (II), Ni (II) and Cr (III) can be removed.
Metal nanoparticles
Magnesia nanoparticles (5-100 nm): Effective biocide against gram positive and gram negative bacteria and bacterial spores
Gold nanoparticles (20-100nm): Palladium coated nanoparticles are effective catalyst for removing TCE (Trichloroethane) from groundwater.
Silver nanoparticles (1-40nm) : acts as an anti-microbial, anti-biotic and anti- fungal agent
Zeolites
Zeolite nanoparticles are prepared by laser- induced
fragmentation.
An effective sorbent and ion exchange media for metal ions.
Porous structure
Can accommodate variety of cations
Na+,K+,Ca2+,Mg2+ etc.......
These ions can be readily exchanged
NaP1 zeolites (Na6Al6Si10O32.. 12H2O)
have a high density of Na+ ion-
exchange sites.
Experiments have reported the
successful use of synthetic NaP1
zeolites to remove Cr (III), Ni (II), Zn
(II), Cu (II) and Cd (II) from wastewater.
Carbonaceous nanomaterials
High capacity selective sorbents for organic solutes
Shows antibacterial properties
Includes polymers like
azidated polyvinyl chloride, PEG polymer,
Polyethylene mine (PEI) etc...
Polymers are poly cationic agents
HOW IT SHOWS ANTIBACTERIAL ACTIVITY????
Occurrence of new micro contaminants is a challenge to
mankind.
Nanoparticles have the ability to penetrate into the cell
cytoplasm.
Positively charged materials are absorbed on negatively
charged
cell surfaces.
Disruption of cell membranes
MECHANISMS OF REMOVING POLLUTANTS
Nanosorption
Nanofiltration
Photocatalysis
NANOSORPTION
Nanoparticles have larger surface area.
It can be enhanced with various reactive groups to
increase their chemical affinity towards target
compounds.
Activated carbon is the widely used adsorbent in
conventional methods.
Higher efficiency with the use of CNTs and metal based
nanosorbents
Major drawbacks of activated carbon
Contains a significant number of micropores inaccessible to
bulky organic molecules.
Low affinity for low molecular weight polar organic
compounds.
Carbon nanotubes (CNTs) & Metal nanosorbents
From planar sheet of graphite (Graphene)
Available surface area for adsorption on individual CNTs is their
external surfaces.
Hydrophobicity of graphitic surface.
Peng (2005) discovered Cerium oxide supported CNTs are
effective sorbents for arsenic .
Nanomaterials can remove heavy metals.
Metal based nanosorbents are used for the removal of arsenic.
NANOFILTRATION
A pressure driven membrane separation process.
Falls between ultrafiltration and reverse osmosis.
Low pressure membrane process (7-30 bar)
Nanofiltration membrane has pore size 1-5 nm
Higher flux rate
Allows the transmission of monovalent ions but multivalent ions
are largely retained.
Nanofiltration membranes have been shown to remove
Turbidity
Microorganisms
Inorganic ions (Ca , Na)
Nitrates and arsenic from groundwater
Organic pollutants
Carbon nanotube filters
Nanoceramic filters
PHOTOCATALYSIS
An advanced oxidation process
Major barrier for its wide application is slow kinetics
TiO2 is the most widely used photocatalyst
Ti exists naturally in three different forms rutile, anatase,
brookite.
Anatase is most often used in photocatalysis
Steps involved in degradation of organic compounds
1. External diffusion of reactant to photocatalyst surface.
2. Adsorption of contaminant.
3. Reaction of adsorbed organic compound with photo-excited
photocatalyst.
4. Desorption of reaction products.
5. Mass transfer of reaction product to bulk water.
How it works ???
ADVANTAGES OVER CONVENTIONAL METHODS
Efficient
Reliable
High capacity
Regenerative
Stable
DRAWBACK
Scale up is difficult
High cost
CONCLUSION
The unique properties of nanomaterials and
their convergence with current treatment technologies
present great opportunities to revolutionize water and
wastewater treatment.
REFERENCES:
1. Sayan Bhattacharya, Indranil Saha, Anirudda
Mukhopadhyay, Dhrubajyoti Chattopadhyay,Uday Chand Gosh and Debashis Charrerjee (2013), Role of nanotechnology in water treatment and purification: Potential applications and implications, International Journal of Chemical Science and Technology, ISSN 2249-8532
2. M. T. Amin, A. A. Alazba, and U.Manzoor (2014), A Review of Removal of Pollutants from Water/Waste water Using Different Types of Nanomaterials, Journal of Advances in Materials Science and Engineering, Volume 2014,Article ID: 825910
3. Karishma K. Chorawala, Mehali J. Mehta (2015),Applications of Nanotechnology in Wastewater Treatment, International Journal of Innovative and Emerging Research in Engineering, Volume 2,Issue 1,ISSN:2394-5394
4. Bernd Nowak (2008), Pollution Prevention and Treatment Using Nanotechnology, Volume 2, Environmental Aspects, Edited by Harald Krug, ISBN: 978-3-527-31735-6
5. Xiaolei Qu, Pedro J.J. Alvarez, Qilin Li (2013),Application of nano technology in water and wastewater treatment, SciVerse Science Direct, ISSN 3931-3946
6. Dhermendra K. Tiwari, J. Behari and Prasenjit Sen (2008),Applications of Nanoparticles in Waste Water Treatment, World Applied Sciences Journal 3 (3) 417-433,2008,ISSN 1818-4952
7. D.M Johnson, D.R. Hokanson, Q. Zhang, K.D.Czupinski and J.Tang (2008), Feasibility of water purification technology in rural areas of developing countries ,Journal of Environmental Management,Vol.88,no.3,pp.416-427
Quotes!!!!
“The wars of the twenty-first century will be fought over water “ Ismail Serageldin
THANK YOU
ALL!!!!
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