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!!!!

QUERIES