Affordable clean water using nanotechnology

T. PradeepDepartment of Chemistry and Sophisticated Analytical Instrument Facility

Indian Institute of Technology MadrasChennai 600 036, INDIA

http://www.dstuns.iitm.ac.in/pradeep_research_group.php

Potential Environmental Benefits of Nanotechnology: Fostering safe innovation-led growth OECD July 15-17, 2009

Celebrating 50 years

It is the poor who drive our society.

Chapter by T. Pradeep and Anshup

O

H H

99.84 pm

104.45O

2 nm

Gas hydrates to ozone chemistry

Claude Monet, Waterlilies, 1906

Oil on Canvas, The Art Institute of Chicago

Water - prosperity, health, serenity, beauty, artistry, purity …..

Water - ―the vehicle of nature" ("vetturale di natura‖) – Leonardo Da Vinci

Subject: Leonardo, Old Man with Water Studies, c. 1513

Leonardo

Old Man with Water Studies, c. 1513

Leonardo

Machine for raising water

Mohenjodaro - well

Mohenjodaro – the great bath

Aqueducts - The Assyrians

- the first structure to carry

water from one place to

another - 7th century BC

Archimedes’ screw - 287 and 212

BC - in the Netherlands

Zoetermeer

Water and civilizations

http://dspace.rice.edu/bitstream/1911/9176/773/LanMa1890_135_a.jpg

hof.povray.org/River.html

Microbes Heavy metals Chemicals,

pesticides

Nitrates

Fluoride

Asbestos

……

Water filtration: various media

Year

1804 Setup of world's first city-wide municipal water treatment plant (Scotland, sand-filter technology)

1810 Discovery of chlorine as a disinfectant (Humphrey Davy)

1852 Formulation of Metropolis Water Act (England)

1879 Formulation of Germ Theory (Louis Pasteur)

1902 Use of Chlorine as disinfectant in drinking water supply (calcium hypo chlorite, Belgium)

1906 Use of ozone as disinfectant (France)

1908 Use of Chlorine as disinfectant in municipal supply, New Jersey

1914 Federal regulation of drinking water quality (USPHS)

1916 Use of UV treatment in municipal supplies

1935 Discovery of synthetic ion exchange resin (Adams, Holmes)

1948 Nobel Prize to Paul Hermann Müller (insecticidal properties of DDT)

1959 Discovery of synthetic reverse osmosis membrane (Yuster, Loeb, Sourirajan)

1962 Publishing of Silent Spring, first report on harmful effects of DDT (Rachel Carson)

1965 World's first commercial RO plant launched

1974 Reports on carcinogenic by-products of disinfection with chlorine

Formulation of Safe Drinking Water Act (USEPA)

1975 Development of carbon block for drinking water purification

1994 Report on use Zerovalent Iron for degradation of halogenated organics (Gillham, Hannesin)

1997 Report on use Zerovalent Iron nanoparticles for degradation of halogenated organics (Wang, Zhang)

1998 Drinking Water Directive applied in EU

2000 Adoption of Millennium Declaration during the UN Millennium Summit (UN Millennium Development Goals)

2003 Report on use Noble metal nanoparticles for degradation of pesticides (Nair, Tom, Pradeep)

2004 Stockholm Convention, banning the use of persistent organic pollutants

2007 Launch of world's first nanotechnology based domestic water purifier (Pradeep, Eureka Forbes Limited)

Milestone

Important milestones in the history of water purification (1800-2007)

Source: Multiple sources from internet

Credits to several governments, organizations and individuals, we have moved ahead. Now,

the journey of “pure water for all” calls for next big innovation.

Last globally big invention in

water purification

Economic and technical assessment of desalination technologies, Fawzi Banat, From Red Sea to Dead Sea — Water and Energy,

Geneva, June 6-8, 2007 www.desline.com/Geneva/Banat.pdf

The cost of RO solutions has seen a dramatic fall since the discovery, but

the costs have flattened recently.

Costs analysis of Reverse Osmosis Plants(converted to 1995 base year level)

Review of major contaminants in drinking waterMajor

pollutant

Sources of

origin

Permissible

limits

Affected countries Population at risk

(estimates)

Health effects Remarks

Pesticides - Farming,

effluents,

home use

DDT: 1 ppb

Carbofuran:

40ppb

Simazine: 4 ppb

US, Kenya, Egypt,

India, European Union,

Africa, China,

Australia

Poisoning: 28 million

agricultural workers in

developing countries.

~18,000 deaths

Cancer, cardiovascular/

reproductive/

neurological disorders,

Liver/kidney problems

Pesticide

contamination in soft

drinks, Union Carbide

Bhopal tragedy (India)

Halogenated

organics

Chlorination,

effluents,

home

insecticide

CCl4: 5 ppb

TCE: 5 ppb

TTHMs: 80 ppb

Japan, Central Asia,

Arabian Peninsula,

Sweden, Poland,

Germany, USA, Egypt,

China

~180 million people in

US consume

chloraminated water

-CCl4: High toxicity to

liver and kidney,

carcinogenic. TCE:

Lung/liver tumor

- 25 million pounds

TCE were released in

the U.S. environment

by manufacturing

plants in 1995

Fluoride - Geological

origin,

mineral

weathering,

coal mining

2 ppm Asia, Mexico,

Australia, Argentina,

Africa, New Zealand

62 million (India) - Dental and skeletal

fluorosis, Muscle fibre

regeneration, nervous

system malfunction

A union of 1,200

scientists, doctors and

lawyers announced

opposition to water

fluoridation (1999)

Arsenic - Geological

origin

10 ppb Bangladesh, India,

China, Pakistan,

Nepal, Myanmar,

Vietnam

65 million (Asia) High blood pressure,

glucosuria,

hyperpigmentation,

keratoses, cancer

- Death rate: 1 in 100

people (Conc: 50 ppb)

and 10 in 100 people

(Conc: 500 ppb)

Mercury - Industrial

pollution,

dental filling,

Food (fish)

2 ppb Indonesia, China,

Africa, Philippines,

Japan, Kazakhstan,

USA, Brazil, Australia,

Taiwan, EU

~630,000 infants are

born with high Hg

content in the blood

every year (EPA)

Neurotoxicant, tremors,

respiratory failure,

gastrointestinal failures,

and kidney damage

- ~30% of the mercury

in US comes from

abroad e.g. China -

Unilever plant,

Kodaikanal. Minamata,

Niigata, River Nura.

Lead - Old piping

lines, mineral

weathering,

paint

15 ppb Egypt, EU, USA,

Thailand, China,

Cambodia

>300,000 US children

and 65% of Shanghai

children have high lead

concentration

Delays in physical or

mental development,

Kidney problems, high

blood pressure

- Incidence of Gout due

to leaded wine and

rum- Use of lead in

paints and discharge in

environment

Review of major drinking water contaminants, their health impacts and a few associated eventsmultiple sources from internet

Fluoride contamination: Indian Scenario

• 25 million people are suffering from fluorosis and 62 million are

at the risk of fluorosis

Quantum of Fluoride Contamination

Despite being a global contaminant, fluoride is still a unresolved mystery.

A.K. Susheela, Fluorosis management programme in India, Current Science 77 (10) (1999) 1250–1256

0.47 Subernarekha River, West Bengal

0.59 Hugli River, West Bengal

0.85 Saptamukhi River, West Bengal

0.68 Matla River, West Bengal

0.70 Bellandur Lake, Bangalore

Conc(mg/l)

Location

0.47 Subernarekha River, West Bengal

0.59 Hugli River, West Bengal

0.85 Saptamukhi River, West Bengal

0.68 Matla River, West Bengal

0.70 Bellandur Lake, Bangalore

Conc(mg/l) Conc(mg/l)

LocationLocation

Fresh water (Source: PCB)

0.013NTDelhiNazafgarh

0.042<0.005RajasthanJodhpur

0.2240.005RajasthanPali

0.150NTHimachal PradeshKala Amb

0.062NTHimachal PradeshParwanoo

0.08NTPunjabGobindpur

0.01NTUtter PradeshSingrauli

0.01NTMadhya PradeshKorba

MaxMin

Cd (mg/l)StateLocation

0.013NTDelhiNazafgarh

0.042<0.005RajasthanJodhpur

0.2240.005RajasthanPali

0.150NTHimachal PradeshKala Amb

0.062NTHimachal PradeshParwanoo

0.08NTPunjabGobindpur

0.01NTUtter PradeshSingrauli

0.01NTMadhya PradeshKorba

MaxMaxMinMin

Cd (mg/l)Cd (mg/l)StateStateLocationLocation

Ground water (1995-96) (Source: PCB)

NT-2.9 (1999)East Coast

2-25 (1994)Parangipettai Coast

0.98 (1991)River Coovum

1.4 (1987)Madras Coast

2-27 (1994)Cuddalore

0.1-0.6 (1991)Point Calimere

80.00 (1980)Off Bombay

Conc.(μg/l)Location

NT-2.9 (1999)East Coast

2-25 (1994)Parangipettai Coast

0.98 (1991)River Coovum

1.4 (1987)Madras Coast

2-27 (1994)Cuddalore

0.1-0.6 (1991)Point Calimere

80.00 (1980)Off Bombay

Conc.(μg/l)Location

Coastal water (Source: PCB)

• The Palakkad controversy showed that excessive withdrawal of ground water can also expose us to high metal contamination

• The above figures are just a tip of the iceberg (itai-itai)

– India produces 1.46L tons of e-waste annually

– In India, 2M of computers become obsolete every year

– 67,000 tons of computer waste contributed 1.1 tons Hg, 4.5 tons Cd and 3012 tons Pb into landfills (Canada, 05)

– The average Cd generation per computer is 2.8 g

How much of our environment is polluted by cadmium?

Affordable Drinking Water Purifier – Market needs

Mercury contamination, Minamata,

Japan, 1956

Fluoride contamination, India, 2003Pesticide contamination, Kerala, 2001

Microbial contamination, Zimbabwe, 2009

Unsolved technology problems

Images collected from arsenic, fluoride and pesticide affected areas in India

For 8-month old Sainaba to 18-year old Ramaswamy, science still has to deliver its benefits

Pictures from the web

Affordable Drinking Water Purifier – Market needs

Commercial unviability – Pricing issues

Brand Aquasana Amway Culligan Kenmore GE Ever Pure Aqua-Pure PUR Brita Brita

Model

Number

AQ-4000 E-5199 SY-2300 Deluxe

38465

Smart Water

GXSV10C

H-54 DWS1000 Plus FM-

3000

Faucet Filter Pitcher

Filter

Retail

Price

$124.99 $420.00 $159.99 $149.99 $139.99 $149.99 $349.95 $49.95 $34.95 $24.95

Replacem

ent Cost

&

Capacity

$48.00 /

500 Gal.

$120.00 /

1250 Gal.

$50.39 /

500 Gal.

$49.00 /

500 Gal.

$60.00 / 540

Gal.

$79.95 / 750

Gal.

$79.99 / 625

Gal.

$20.00 / 100

Gal.

$20.00 / 100

Gal.

$7.70 / 30

Gal.

Cost per

gallon

9.6 ¢ Per

Gal.

9.6 ¢ Per

Gal.

10¢ Per

Gal.

9.8¢ Per

Gal.

11¢ Per Gal. 10.6¢ Per

Gal.

13¢ Per Gal. 20¢ Per

Gal.

20¢ Per Gal. 25¢ Per

Gal.

Chlorine >99% 97.9% 97% 99% 97% 96% 97% 98% 99% >75%

Lead >99% 98% 95% 92% 98% 97% 95% 96% 99% 93%

Cysts >99.99% 99.5% 99% NO >99% >99% >99% 99.99% 99.99% NO

THMs >99% >99% 95% 99% 95% NO 92% NO NO NO

VOCs >99% >99% 95% 95% 99% NO 92% NO NO NO

Lindane >99% 72.7% 99% 99% 99% NO >99% 97% 99% NO

Alachlor >98% 95% 98% 95% 98% NO 98% NO 99% NO

Atrazine >97% >97% 97% 97% 97% NO 97% 96% 92% NO

Benzene >99% >97% 99% 83% 99% NO >99% NO 96% NO

TCE >99% >98% 99% 98% 99% NO >99% NO 99% NO

MTBE >97% NO 90% NO NO NO NO NO NO NO

Cost per

1000 gals.

$172.99 $420.00 $210.38 $198.99 $199.99 $229.90 $349.95 $229.95 $214.95 $273.91

Our goals of a socially relevant science has largely failed due to

our inability to serve people at bottom-of-the-pyramid

Affordability of Technology

• What does this cost-of-ownership for access to pure water and income-based societal structure mean

to us?

– Need for a revolutionary theme for guaranteeing access to pure water to everybody - under INR

1,000 water purifier (<$20)

• Universal purifier: Remove suspended particles, pesticides, microbes, metals and anions

• Zero electricity

• Minimum maintenance and low-cost of annual replacement (< INR 450/-) (<$10)

• Indeed, early signs of success of nanotechnology gives a ray of hope

INR 7590

($ 168)

Turbidity, Chlorine, Bacteria, Virus,

OdorINR 7690

($ 171)

Turbidity, Chlorine, Bacteria, Virus,

OdorINR 9,590

($ 213)

Turbidity, Chlorine, Bacteria,

Virus, Odor, Pesticides

INR 15,500

($ 345)

TDS, Taste, Heavy metals,

pesticides, F-/NO3

-

INR 2,000

($ 45)Turbidity, Chlorine, Bacteria, Virus

INR 650

($ 15)Turbidity, Chlorine, Bacteria, Virus

- Bacteria, Virus

INR 250

($ 6)-

Reference: Eureka Forbes Ltd, Bangalore (2008)

Bottled Water

Rs 0.61

Rs 0.70

Rs 0.94

Rs 1.86

Rs 0.33

Rs 0.18

Rs 2.0

Aquasure on Tap Rs 0.12

Aquaguard Gold

Nova

Aquaguard RO

Aquasure 4-in-1

Boiling

Average cost

per liter (10 yrs)

Aquaguard Classic

Aquaguard Nova and I-

Nova

Product

Price

Products from

Eureka Forbes LtdFunctions

Income

Segment

Annual Household

Income ($)

# of

Households

(in '000)Community <$ 2,000 132,249

$2,000-$4,500 53,276

$4,500-$11,000 13,183

$11,000-$22,000 3,212

$22,000-$44,000 1,122

$44,000-$111,000 454

$111,000-$222,000 103

$222,000 52

Source: www.ncaer.org - Year 2005

High-Budget

Low-Budget

An object for the nanotechnology - nanomaterials

2 nm

5 nm5 nm5 nm

20 nm

A

0 100 200 300 400

0

5

10

15

20

Hei

ght (

nm)

Distance (nm)

B

C

200 nm

100 nmDD400 600 800 10000.0

0.2

0.4

0.6

Abs

orba

nce

I

II

III

Wavelength (nm)

Range of nanostructured materials

http://www.nano-

lab.com/imagegallery.html

http://www.physics.upenn.edu/~dr

ndic/group/graphene.html

PJF Harris et. al., J. Phys.: Condens.

Matter 20 (2008) 362201

Y. Xia et. al., Adv. Mater 2002,

14,11,833

STM image of MoS2 nanoflakes. From, Nanotechnology

14, pp. 385-389 (2003)

Nanocatalysis

USEPA has played a key role in determining the

regulations for many toxic species found in drinking water

Regulatory coverage of USEPA for safe drinking water has increased over 4times since its inception, with revisions in regulations of many old contaminants

1

3

1

4

2

9

1

5

1 1 1 1 1 1 1

6 67

9

15

21

10

5

2

44

65

13

4

0

5

10

15

20

25

r q p o n m l k j i h g f e d c b a

Label for contaminants

Nu

mb

er o

f co

nta

min

ants

1

3

1

4

2

9

1

5

1 1 1 1 1 1 1

6 67

9

15

21

10

5

2

44

65

13

4

0

5

10

15

20

25

r q p o n m l k j i h g f e d c b a

Label for contaminants

Nu

mb

er o

f co

nta

min

ants

Candidate contaminant list

Contaminants regulated by EPA

(a): Halogenated organic (b): Metal (c): Organochlorine pesticide (d): Inorganic

salt (e): Biological contaminant (f): Nuclear (g): Benzo derivative (h): Carbamate

pesticide (i): Pesticides (others) (j): Unclassified (k): Triazine derivative pesticide

(l): Organophosphorus pesticide (m): Organobromine pesticide (n): Non-metal

(o): Nitrophenol derivative, (p): Dioxin, (q): Benzo and halogenated organic (r):

Organometallics

Category-wise distribution of contaminants regulated by USEPA and future contaminants

Future of water purification: An enigma with some pointers

Continued focus of USEPA regulatory activities on various other halogenated organics found

in drinking water. The allowed concentration limits for a number of species may shift to sub-

ppb range.

Source: www.epa.org and www.who.int

10

100

50

100

50

50

200

0

50

100

150

200

1950

1960

1970

1980

1990

2000

Year

Co

nce

ntr

atio

n (

in p

pb

)

Lead

Arsenic

Changes in maximum allowable concentration for lead and arsenic in drinking

water, based on WHO advisory

Future of water purification: Shrinking limits for allowed concentration of

contaminants in water

Nanotechnology holds the future for effectively

removing many drinking water contaminants

- Number of contaminants present in extremely low concentration range (<1015 molecules per glass of water) are quite significant

- Many of those contaminants contain C-Cl bond or are metallic in nature

Perm

issib

le co

nta

min

ation

Time

Permissible contamination reaches limits of detection

1012 molecules

Organics

Pesticides

Traditional methods (activated carbon, membranes)

Nanomaterials

Metals, oxides, clays, dendrimers

Tansel and Nagarajan, Advances in Environmental Research 8, 2004, 411–415

Plakas, Karabelas, Wintgens and Melin, Journal of Membrane Science 284, 2006, 291–300

Illustration of metal adsorption on nanoparticle surface (ZVI surface)

XPS wide-scan survey of iron nanoparticles after exposure to a metal

salt containing solution, Sequestration of Metal Cations with Zerovalent

Iron Nanoparticless A Study with High Resolution X-ray Photoelectron

Spectroscopy (HR-XPS), Xiao-qin Li and Wei-xian Zhang, J. Phys.

Chem. C 2007, 6939-6946

TEM image of Fe nanoparticle and Cartoon representation of chemistry at Fe

nanoparticle, Iron Nanoparticles: the Core-Shell Structure and Unique

Properties for Ni(II) Sequestration, Xiao-qin Li and Wei-xian Zhang, Langmuir

2006, 4638-4642

Cartoon representation of chemistry at Fe nanoparticle surface (left) and metal ion removal efficiency for different adsorbents, Iron Nanoparticles: the Core-Shell

Structure and Unique Properties for Ni(II) Sequestration, Xiao-qin Li and Wei-xian Zhang, Langmuir 2006, 4638-4642

(L) HR-XPS survey on the Ni 2p3/2 of iron nanoparticles (R) a conceptual model for nickel deposition on

iron nanoparticles

Metal adsorption on nanoparticle surface (ZVI surface)

Binding energy (eV)859 856 853 850

Co

un

ts (

X 1

04 )

0

0.6

1.2

1.8

2.4

Ni2+Ni0

24 hrs

3 hrs

1 hr

15 min

(b) (c)Ni(II) Ni(II)

Reduction

Ni(0)

Fe(0)Fe(0) FeOOH

Sorption

Ni2+ + 2e- → Ni Eº = -0.25 V

Fe → Fe3+ + 3 e- Eº = 0.44 V

96 99 102 105 108 111

After 24 hrs

Ag@citrate-Hg(OAc)2

105.4

104.2100.2

101.4

100 ppm

7 ppm

50 ppm

10 ppm

Hg(II)

Hg(0)

Hg 4f5/2

Hg 4f7/2

Co

un

ts

Binding Energy (eV)

Bootharaju et al. Unpublished

(a) Schematic illustration of ceramic membranes and TEM images of the boehmite (top) and

titanate (bottom) nanofibers, (b) SEM image of feed water containing 60 nm latex spheres

and permeate water (inset). Filtration efficiency=96.8%

(a) (b) 1 μm

1 μm

X.B

. Ke,

Z.F

. Zhe

ng, H

.W. L

iu, H

.Y. Z

hu, X

.P. G

ao,

L.X

. Zha

ng, N

.P. X

u, H

. Wan

g, H

.J. Z

hao,

J. S

hi,

K.R

. Rat

inac

, J. P

hys.

Che

m. B

112

(20

08)

5000

.X

.B. K

e, H.Y. Z

hu, X.P. G

ao, J.W. Liu, Z

.F. Zheng,

Adv. M

ater. 19 (2007) 785

Metal oxide and MWNT assembly based membrane filtration

0 sec 15 sec 30 sec

45 sec 60 sec 80 sec

Pt wire(a) (b)

Images of water droplet shape change with a +2.6 V potential applied with a multiwalled

nanotube film as anode and Pt wire as cathode. The droplet sinks into the nanotube membrane

in about 90 s. (b) SEM image of a cylindrical macrostructure assembly showing the wall of the

bulk tube consisting of aligned MWNTs with lengths equal to the wall thickness (scale 100 μm)

G. H

umm

er, J

.C. R

asai

h, J

.P. N

owor

yta,

Nat

ure

414

(200

1) 1

88.

Z.W

ang, L. Ci, L. C

hen, S. N

ayak, P.M.

Ajayan, N

. Koratkar, N

ano Lett. 7 (2007) 697

--

+

+

+

+

+

+

+

-

-

----

-

-

-

++

++

++

++

++

++

++

400 600 800 10000.0

0.2

0.4

ba

Ab

sorb

ance

Wavelength(nm)

With

Endosulfan

A

B C

A

B C

Gold

nanoparticles

300 500 700 900

0.6

300 500 700 900A

bso

rban

ce0

0.2

0.4A

B C

A

B C

Gold

nanoparticles

With mercury

Wavelength (nm)300 500 700 900

0.6

300 500 700 900A

bso

rban

ce0

0.2

0.4A

B C

A

B C

Gold

nanoparticles

With mercury

Wavelength (nm)

Heavy metals

Halogenated organics & pesticides

Bacteria & virus

Noble metal nanomaterials: Novel chemistry for water purification

The novel chemistry of noble metal nanomaterials help them target broad range of toxic

contaminants. We will see a glimpse of it in the later slides.

Reactions with pesticides

Endosulfan

Color changes with pesticide concentrationGood response at lower concentrationsDown to 0.1 ppmAdsorbed pesticides can be removed from solution

Color of gold nanoparticles with endosulfan

Endosulfan concentration in ppm

02100 200

Example

Pesticide removalIndian Patent grantedInternational patent filedTechnology commercialized

J. Environ. Monitoring. 2003

Some of the pesticides contain halocarbons whereas others

have P or S, which can bind metal nanoparticles which is used

for pesticide detection and extraction.

Endosulfan Chlorpyrifos Malathion

400 500 600 700 800 900 1000 1100

0.0

0.1

0.2

0.3

0.4

0.5

edcba

Abs

orba

nce

Wavelength(nm)400 500 600 700 800 900 1000 1100

0.0

0.1

0.2

0.3

0.4

c

b

t

a

Abs

orba

nce

Wavelength (nm)

UV-visible spectra of gold nanoparticles showing the detection

of endosulfan at different concentrations (b.2, c.10, d.100 and

e. 250 ppm). Inset (A-D): Color changes of the solutions

corresponding to traces a, b, c and d, respectively.

Time dependent adsorption of endosulfan on gold nanoparticles

and the corresponding spectral changes (a-t). The shifts in the

plasmon band are due to the binding of the pesticide on the

nanoparticle surface.

Endosulfan Chlorpyrifos Malathion

Activated alumina globules (A) and gold (B) and silver (C)

nanoparticles coated on the same.

4 cm

Supported nanoparticles for pesticide removal

Silver nanoparticles coated on activated alumina

(neutral) powder

These can be made in ton quantities.

Absorption spectra showing the time dependent removal of 1 ppm chlorpyrifos (left) and

malathion (right) by supported nanoparticles. The reduction in the absorbance feature

with time is due to the adsorption of the pesticides on the nanosurface. Inset shows

reduction in absorbance with time. Time interval between spectra was 20 minutes.

300 400 500 600 700 8000.00

0.05

0.10

0.15

Absorb

ance

Wavelength (nm)

s

r

c

b

a

0 100 200 300 400 500 6000.00

0.04

0.08

0.12

0.16

Ab

so

rba

nce

Time (minutes)

300 400 500 600 700 800

0.00

0.05

0.10

0.15

q

p

c

b

a

Absorb

ance

Wavelength (nm)

0 100 200 300 400 500 6000.00

0.04

0.08

0.12

Absorb

an

ce

Time (minutes)

Nanoparticle loaded alumina can remove pesticides

400 600 800 1000

0.00

0.05

0.10

b-e

a

Ab

so

rba

nce

Wavelength (nm) 3000 2500 2000 1500 1000 500

30

40

50

60

70B

a

% Tr

ansm

ittanc

e (Ar

b.Unit

s)

Wavenumber (cm-1)

b

3000 2500 2000 1500 1000 50020

40

60

80

100

A

% Tr

ansm

ittanc

e (Ar

b.Unit

s)

a

b

Absorption spectra showing the complete removal ofpesticides when contaminated water was passed througha column of the nanomaterial. Trace a is the spectrum ofthe parent pesticide solution, b-e after passing throughthe nanoparticle-loaded column, in repeated experiments.

Infrared spectra of the free pesticides (a) and that adsorbedon the nanoparticle surfaces (b) chlorpyrifos (A) andmalathion (B).

Other scientific tests conducted confirm the complete removal of commonly

occurring pesticides from water

Product of this reaction is amorphous carbon

400 600 800 10000.0

0.5

1.0

1.5

Ab

sorb

ance

Wavelength (nm)

p

o

ba

A B

Time (min)2 4

-600

-400

-200

0

200

400

0Time (min)

2 40

-0.5

0.0

0.5

[V]

2.14

2.5

2.93

3

3.30

7C

P

[mV]

(a) Time (min)2 4

-600

-400

-200

0

200

400

0Time (min)

2 40

-0.5

0.0

0.5

[V]

2.14

2.5

2.93

3

3.30

7C

P

[mV]

Time (min)2 4

-600

-400

-200

0

200

400

0Time (min)

2 40

-0.5

0.0

0.5

[V]

2.14

2.5

2.93

3

3.30

7C

P

[mV]

(a)

(b)

(c)(c)

Noble metal nanoparticles: removal of pesticides from water

Variation of the UV-visible absorption

spectrum of silver nanoparticles upon

the addition of CCl4

Gas chromatogram of chlorpyrifos solution (L) and after

treatment with silver nanoparticles (R)

(L) Silver nanoparticles coated on activated alumina (R) Photograph of a pesticide filter device using supported

nanoparticles (WQA certified)

A.S

. Nai

r, T.

Pra

deep

, Cur

r. S

ci. 8

4 (2

003)

156

0A

.S. N

air,

R.T

. Tom

, V.R

. Raj

eev

Kum

ar,

C. S

ubra

man

iam

, T. P

rade

ep, C

osm

os

3, (

2007

) 10

3 June 2007

Product is marketed now

Cartridges are recovered after use

A pesticide test kit has been developed > 25 ppb

C

20nm

Wavelength (nm)300 500 700 900

Ab

sorb

ance

0

0.2

0.4

0.6A BA Bba

ab

C

20nm

Wavelength (nm)300 500 700 900

Ab

sorb

ance

0

0.2

0.4

0.6A BA Bba

ab

20 nm

(A)

100nm

(B)

(C)

+++++

+

+*

*

b

+

+

(100

) (00

2)

(101

)

(102

)

(110

)

(103

)

(112

)(2

01)

(004

)(2

22)

(111

)

(111

)(2

00)

(220

)

(311

)(2

22)

a

2θ (degrees)30 50 70 806040

Inte

nsi

ty

+++++

+

+*

*

b

+

+

(100

) (00

2)

(101

)

(102

)

(110

)

(103

)

(112

)(2

01)

(004

)(2

22)

(111

)

(111

)(2

00)

(220

)

(311

)(2

22)

a

2θ (degrees)30 50 70 806040

Inte

nsi

ty

(D)

C

20nm

Wavelength (nm)300 500 700 900

Ab

sorb

ance

0

0.2

0.4

0.6A BA Bba

ab

C

20nm

Wavelength (nm)300 500 700 900

Ab

sorb

ance

0

0.2

0.4

0.6A BA Bba

ab

20 nm

(A)

100nm

(B)

100nm

(B)

(C)

+++++

+

+*

*

b

+

+

(100

) (00

2)

(101

)

(102

)

(110

)

(103

)

(112

)(2

01)

(004

)(2

22)

(111

)

(111

)(2

00)

(220

)

(311

)(2

22)

a

2θ (degrees)30 50 70 806040

Inte

nsi

ty

+++++

+

+*

*

b

+

+

(100

) (00

2)

(101

)

(102

)

(110

)

(103

)

(112

)(2

01)

(004

)(2

22)

(111

)

(111

)(2

00)

(220

)

(311

)(2

22)

a

2θ (degrees)30 50 70 806040

Inte

nsi

ty

(D)

Noble metal nanoparticles: removal of heavy metals from water

(Left) Large area TEM image of gold nanoparticles (A) before Hg(0) treatment (B) after Hg(0) treatment

(Center) UV-vis absorption spectra of gold nanoparticles before and after mercury treatment (Inset: photographs)

(Right) XRD patterns of gold nanoparticles (D) before and (E) after mercury treatment (symbols: + Au3Hg, * Au)

K.P

. Lis

ha, A

nshu

p, T

. Pra

deep

, Gol

d B

ull.

42 (

2009

) 14

4

200 400 6000.00

0.05

0.10

(viii)(ix)

(ii)

(i)

Hg2+

(50ppm, 50ml) with Ag NP (5ml)

Wavelength (nm)

Ab

sorb

ance

(a)

(b)

5 μm

(b)

Ag|Si Hg|Si2 μm

(a) (b) (c)

Noble metal nanoparticles: removal of heavy metals from water

(a) UV-vis absorption spectra of silver nanoparticles (i) before Hg2+ treatment (ii-ix) after

Hg2+ treatment. (b) Large area SEM image of the Ag-Hg bimetallic nanoparticles

(a) SEM image of an Ag-Hg alloy nanoparticle, (b) elemental image of Ag and (c) elemental image

of Hg overlaid on Si (Si is from ITO substrate).

T. P

rade

ep e

t al (

unpu

blis

hed)

Concentration of silver (µg)0 40 80 0 40 80

0 40 80 0 40 80

log

(1+

X)

0

2

4

6

8

0

2

4

6

8

0

2

4

6

8

0

2

4

6

8

AgNO3

R2 = 0.98

Rod

R2 = 0.9689

Sphere

R2 = 0.9878

Triangle

R2 = 1

(B)

Concentration of silver (µg)0 40 80 0 40 80

0 40 80 0 40 80

log

(1+

X)

0

2

4

6

8

0

2

4

6

8

0

2

4

6

8

0

2

4

6

8

AgNO3

R2 = 0.98

Rod

R2 = 0.9689

Sphere

R2 = 0.9878

Triangle

R2 = 1

(B)a b

c d

a b

c d

a b

c d

a b

c d

(A) AgNO3 Rod

Sphere Triangle

Noble metal nanoparticles: removal of bacteria (E. coli) from water

(A) Petri dishes initially supplemented with 107 CFU/ml of E. coli and incubated with different forms of silver

nanoparticles at (a) 1, (b) 12.5, (c) 50, and (d) 100 μg. (B) Number of E. coli colonies, expressed as

log(1+number of colonies grown on plates under the conditions used for panel A) as a function of the amount of

silver nanoparticles in agar plates.J.R

. Mor

ones

, J.L

. Ele

chig

uerr

a, A

. Cam

acho

, K. H

olt,

J.B

. Kou

ri, J

.T. R

amire

z,

M.J

. Yac

aman

, Nan

otec

hnol

ogy

16 (

2005

) 23

46

Raman Shift (cm-1)300 500 700 900

SE

RS

Inte

nsi

ty

(a)

Raman Shift (cm-1)300 500 700 900

SE

RS

Inte

nsi

ty

PVPBTHDTMDA

(b)

SE

RS

Inte

nsi

ty

Raman Shift (cm-1)500 600 700 800 900 1000

AsIII + AsV

AsV

(c)

SERS spectra of arsenate ion (1X10-6 M) on (a) LB films of silver nanocrystals (b) LB arrays of silver

octahedra coated with various organic species. BT: benzenethiol, HDT: hexadecanethiol, MDA:

mercaptodecanoic acid. (c) SERS-based speciation of arsenate and arsenite ions (18 ppb)

Noble metal nanomaterials: detection of toxic species

A

B C

A

B C

A

B C

A

B C

A

B C

A

B Ca b c

50 nm 50 nm 50 nm

a b c d e fa b c d e fa b c d e fa b c d e f(A)

(B)

400 500 600 700 800 9000.0

0.1

0.2

0.3 f

e

d

c

b

a

Ab

so

rban

ce

Wavelength (nm) Wavelength (nm)400 600 800

Ab

sorb

ance

0

0.1

0.2

0.3

a

b

c

de

f

(c)(C)

Colorimetric detection of chlorpyrifos using the gold nanoparticle-Na2SO4 system

Au a+Na2SO4 b+50 ppb

CP

b+100 ppb

CPb+500 ppb

CP

b+1 ppm

CP

M. M

ulvi

hill,

A. T

ao, K

. Ben

jaut

hrit,

J.

Arn

old,

P. Y

ang,

Ang

ew. C

hem

. Int

. Ed.

47 (

2008

) 64

56

K.P

. Lis

ha, A

nshu

p, T

. Pra

deep

, J. E

nviro

n. S

ci. H

ealth

B. (

in p

ress

)

PollutantsHarmless products

CO2

TiO2

HCs

Polluted water Purified water

As adsorption

Magnetic Fe3O4 nanopartilcles

Purification by circulation

Magnetic clays for oil cleanup

Antibody tagging

Magnetic hyperthermia

Magnetic batch separation of 16-nm water-soluble Fe3O4 nanocrystals

(A) Fe3O4 solution (B) After application of magnetic field (C) TEM images

of the nanocrystals

Low

-Fie

ld M

agne

tic S

epar

atio

n of

Mon

odis

pers

e F

e3O

4 na

nocr

ysta

ls, C

. T. Y

avuz

, J. T

. May

o, W

W Y

u,

A P

raka

sh, J

C F

alkn

er, S

Yea

n, L

Con

g, H

J S

hipl

ey, A

Kan

, M T

omso

n, D

Nat

elso

n, V

L C

olvi

n, S

cien

ce,

2006

, 314

, 964

iw

Product Name Nanomaterial utilized Contaminants removal Adsorption capacity Product life Product price

Aquaguard Gold Nova, Eureka

Forbes Limited

Silver nanoparticles supported on

alumina

Pesticides and halogenated organics- 6000 liters $50

Adsorbia Titania nanoparticles

Arsenic and disinfection

12-15 gm As(V) and 3-

4 gm As(III) per kg of

adsorbent

- -

AD33, Adedge Technologies, Inc. Iron oxide nanoparticles Heavy metals including arsenic, lead,

chromium, zinc, copper- 3,800-11,400 liters $50

Nanoceram, Argonide Electropositive alumina nanofibers

on a glass filter substrate

Disinfection, natural organic matter,

turbidity, salt, radioactivity, heavy metals - -$3-10 per sq m

2,

$75 per filter

ArsenX, SolmeteX, Inc. Hydrous iron oxide nanoparticles on

polymer substrate

Arsenic, vanadium, chromium, uranium 38 mg of Arsenic per

gm of adsorbent-

$0.07-0.20 per

1,000 liters

(amortized due to

reusability)

Nanopore, Nanovation AG Membrane filters based on ceramic

nanopowder supported on alumina

Disinfection

- - -

Examples of a few nanotechnology-based products in drinking water purification market (compiled from multiple sources

on the World Wide Web)

Commercial interests in drinking water purification

Current developments

Purifiers for specific areas – local issues – seasonal problems

All inclusive solutions

Local manufacture

Community involvement – NGOs

What OECD can do?

A white paper on available technologies

Act as a link between those who need the technology and those who have the solutions

Conduct discussions in places where technologies are needed

E. F. Schumacher

Pure water can be affordable…..

IIT Madras

Thank you all

Nano Mission, Department of Science and Technology

World Gold Council

Well-meaning individuals

Confocal Raman Microscope

Ultramicrotome

QTrap MS

Transmission

Electron Microscope

MALDI TOF MS

Nanoscience and Nanotechnology Initiative of the DST

Scanning Electron Microscope

XPS