Affordable clean water using nanotechnologyT. Pradeep

Department of Chemistry and Sophisticated Analytical Instrument FacilityIndian Institute of Technology Madras

Chennai 600 036, INDIAhttp://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

OH H

99.84 pm

104.45O2 nm

Gas hydrates to ozone chemistry

Claude Monet, Waterlilies, 1906Oil 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

LeonardoOld Man with Water Studies, c. 1513

LeonardoMachine 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

NitratesFluorideAsbestos……

Water filtration: various media

Year1804 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 Jersey1914 Federal regulation of drinking water quality (USPHS)1916 Use of UV treatment in municipal supplies1935 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 launched1974 Reports on carcinogenic by-products of disinfection with chlorine

Formulation of Safe Drinking Water Act (USEPA)1975 Development of carbon block for drinking water purification1994 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 EU2000 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 pollutants2007 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 water

- Incidence of Gout due to leaded wine and rum- Use of lead in paints and discharge in environment

Delays in physical or mental development, Kidney problems, high blood pressure

>300,000 US children and 65% of Shanghai children have high lead concentration

Egypt, EU, USA, Thailand, China, Cambodia

15 ppb- Old piping lines, mineral weathering, paint

Lead

- ~30% of the mercury in US comes from abroad e.g. China -Unilever plant, Kodaikanal. Minamata, Niigata, River Nura.

Neurotoxicant, tremors, respiratory failure, gastrointestinal failures, and kidney damage

~630,000 infants are born with high Hg content in the blood every year (EPA)

Indonesia, China, Africa, Philippines, Japan, Kazakhstan, USA, Brazil, Australia, Taiwan, EU

2 ppb- Industrial pollution, dental filling, Food (fish)

Mercury

- Death rate: 1 in 100 people (Conc: 50 ppb) and 10 in 100 people (Conc: 500 ppb)

High blood pressure, glucosuria, hyperpigmentation, keratoses, cancer

65 million (Asia)Bangladesh, India, China, Pakistan, Nepal, Myanmar, Vietnam

10 ppb- Geological origin

Arsenic

A union of 1,200 scientists, doctors and lawyers announced opposition to water fluoridation (1999)

- Dental and skeletal fluorosis, Muscle fibreregeneration, nervous system malfunction

62 million (India)Asia, Mexico, Australia, Argentina, Africa, New Zealand

2 ppm- Geological origin, mineral weathering, coal mining

Fluoride

- 25 million pounds TCE were released in the U.S. environment by manufacturing plants in 1995

-CCl4: High toxicity to liver and kidney, carcinogenic. TCE: Lung/liver tumor

~180 million people in US consume chloraminated water

Japan, Central Asia, Arabian Peninsula, Sweden, Poland, Germany, USA, Egypt, China

CCl4: 5 ppb TCE: 5 ppb TTHMs: 80 ppb

Chlorination, effluents, home insecticide

Halogenated organics

Pesticide contamination in soft drinks, Union Carbide Bhopal tragedy (India)

Cancer, cardiovascular/ reproductive/ neurological disorders, Liver/kidney problems

Poisoning: 28 million agricultural workers in developing countries. ~18,000 deaths

US, Kenya, Egypt, India, European Union, Africa, China, Australia

DDT: 1 ppb Carbofuran: 40ppb Simazine: 4 ppb

- Farming, effluents, home use

Pesticides

RemarksHealth effectsPopulation at risk (estimates)

Affected countriesPermissible limits

Sources of origin

Major pollutant

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)

Location

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

MaxMin

Cd (mg/l)StateLocation

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 needsCommercial unviability – Pricing issues

$273.91$214.95 $229.95 $349.95 $229.90 $199.99 $198.99 $210.38 $420.00 $172.99 Cost per 1000 gals.

NONONONONONONO90%NO>97%MTBE

NO99%NO>99%NO99%98%99%>98%>99%TCE

NO96%NO>99%NO99%83%99%>97%>99%Benzene

NO92%96%97%NO97%97%97%>97%>97%Atrazine

NO99%NO98%NO98%95%98%95%>98%Alachlor

NO99%97%>99%NO99%99%99%72.7%>99%Lindane

NONONO92%NO99%95%95%>99%>99%VOCs

NONONO92%NO95%99%95%>99%>99%THMs

NO99.99%99.99%>99%>99%>99%NO99%99.5%>99.99%Cysts

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

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

25¢ Per Gal.

20¢ Per Gal.20¢ Per Gal.

13¢ Per Gal.10.6¢ Per Gal.

11¢ Per Gal.9.8¢ Per Gal.

10¢ Per Gal.

9.6 ¢ Per Gal.

9.6 ¢ Per Gal.

Cost per gallon

$7.70 / 30 Gal.

$20.00 / 100 Gal.

$20.00 / 100 Gal.

$79.99 / 625 Gal.

$79.95 / 750 Gal.

$60.00 / 540 Gal.

$49.00 / 500 Gal.

$50.39 / 500 Gal.

$120.00 / 1250 Gal.

$48.00 / 500 Gal.

Replacement Cost & Capacity

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

Pitcher Filter

Faucet FilterPlus FM-3000

DWS1000H-54Smart Water GXSV10C

Deluxe 38465

SY-2300E-5199AQ-4000Model Number

BritaBritaPURAqua-PureEver PureGEKenmoreCulliganAmwayAquasanaBrand

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, Odor

INR 7690 ($ 171)

Turbidity, Chlorine, Bacteria, Virus, Odor

INR 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, VirusINR 650 ($ 15) Turbidity, Chlorine, Bacteria, Virus- Bacteria, VirusINR 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 Ltd Functions Income

SegmentAnnual Household

Income ($)# of

Households 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 4000

5

10

15

20

Heigh

t (nm

)

Distance (nm)

B

C

200 nm

100 nmDD400 600 800 10000.0

0.2

0.4

0.6

Abso

rban

ce

I

II

III

Wavelength (nm)

Range of nanostructured materials

http://www.nano-lab.com/imagegallery.html

http://www.physics.upenn.edu/~drndic/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 4 times since its inception, with revisions in regulations of many old contaminants

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

13

1

42

9

1

5

1 1 1 1 1 1 1

6 67

9

15

21

10

5

2

446

5

13

4

0

5

10

15

20

25

l k j i h f d b

Num

ber o

f con

tam

inan

ts

Candidate contaminant listContaminants 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

5050

200

0

50

100

150

200

1950

1960

1970

1980

1990

2000

Year

Conc

entra

tion

(in p

pb)

LeadArsenic

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

Per

mis

sibl

e c

onta

min

atio

n

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 ZerovalentIron 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

Coun

ts (X

104 )

0

0.6

1.2

1.8

2.4Ni2+ Ni0

24 hrs

3 hrs

1 hr15 min

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

ReductionNi(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 hrsAg@citrate-Hg(OAc)2

105.4

104.2100.2

101.4

100 ppm

7 ppm

50 ppm10 ppm

Hg(II)

Hg(0)

Hg 4f5/2Hg 4f7/2

Coun

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. Z

hang

, N.P

. Xu,

H. W

ang,

H.J.

Zhao

, J. S

hi,

K.R.

Rati

nac,

J. Ph

ys. C

hem.

B 11

2 (20

08) 5

000.

X.B. Ke, H.Y. Zhu, X.P. Gao, J.W. Liu, Z.F. Zheng,

Adv. Mater. 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 multiwallednanotube 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

umme

r, J.C

. Ras

aih, J

.P. N

owor

yta, N

ature

41

4 (20

01) 1

88.

Z.Wang, L. Ci, L. Chen, S. Nayak, P.M.

Ajayan, N. Koratkar, Nano Lett. 7 (2007) 697

-

-

--

-

-

-+

+

+

+

+

+

+

-

-

--

-

-

-+

+

+

+

+

+

+

400 600 800 10000.0

0.2

0.4

ba

Abso

rban

ce

Wavelength(nm)

With Endosulfan

Gold nanoparticles

300 500 700 900

0.6

300 500 700 900Ab

sorb

ance

0

0.2

0.4

Gold nanoparticles

With mercury

Wavelength (nm)300 500 700 900

0.6

300 500 700 900Ab

sorb

ance

0

0.2

0.4

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 othershave 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 11000.0

0.1

0.2

0.3

0.4

0.5

edcba

Abs

orba

nce

W ave length(nm )4 00 5 00 600 700 800 90 0 10 00 11 00

0 .0

0 .1

0 .2

0 .3

0 .4

cb

t

a

Abs

orba

nce

W a v e le n g th (n m )

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 nanoparticlesand 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

Abs

orba

nce

Wavelength (nm)

s

r

cb

a

0 100 200 300 400 500 6000.00

0.04

0.08

0.12

0.16

Abs

orba

nce

Time (minutes)

300 400 500 600 700 800

0.00

0.05

0.10

0.15

q

p

cba

Abs

orba

nce

Wavelength (nm)

0 100 200 300 400 500 6000.00

0.04

0.08

0.12

Abs

orba

nce

Time (minutes)

Nanoparticle loaded alumina can remove pesticides

400 600 800 1000

0.00

0.05

0.10

b-e

a

Abs

orba

nce

Wavelength (nm) 3 0 0 0 2 5 0 0 2 0 0 0 1 5 0 0 1 0 0 0 5 0 0

3 0

4 0

5 0

6 0

7 0 B

a

% T

rans

mitt

ance

(Arb

.Uni

ts)

W a v e n u m b e r ( c m - 1 )

b3 0 0 0 2 5 0 0 2 0 0 0 1 5 0 0 1 0 0 0 5 0 0

2 0

4 0

6 0

8 0

1 0 0A

% T

rans

mitt

ance

(Arb

.Uni

ts)

a

b

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

Infrared spectra of the free pesticides (a) and that adsorbed on the nanoparticle surfaces (b) chlorpyrifos (A) and malathion (B).

Other scientific tests conducted confirm the complete removal ofcommonly occurring pesticides from water

Product of this reaction is amorphous carbon

400 600 800 10000.0

0.5

1.0

1.5

Abso

rban

ce

Wavelength (nm)

po

ba

A B

Time (min)2 4

-600-400-200

0200400

0Time (min)

2 40-0.5

0.0

0.5

[V]

2.14

2.52.9

333.3

07CP

[mV]

(a) Time (min)2 4

-600-400-200

0200400

0Time (min)

2 40-0.5

0.0

0.5

[V]

2.14

2.52.9

333.3

07CP

[mV]

Time (min)2 4

-600-400-200

0200400

0Time (min)

2 40-0.5

0.0

0.5

[V]

2.14

2.52.9

333.3

07CP

[mV]

(a)

(b)

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.

Nair

, T. P

rade

ep, C

urr.

Sci. 8

4 (20

03) 1

560

A.S.

Nair

, R.T

. Tom

, V.R

. Raje

ev

Kuma

r, C.

Sub

rama

niam,

T. P

rade

ep,

Cosm

os 3,

(200

7) 10

3

June 2007

Product is marketed nowCartridges are recovered after use

A pesticide test kit has been developed > 25 ppb

C

20nm

Wavelength (nm)300 500 700 900

Abso

rban

ce

0

0.2

0.4

0.6A BA Bba

ab

C

20nm

Wavelength (nm)300 500 700 900

Abso

rban

ce

0

0.2

0.4

0.6A BA Bba

ab

20 nm

(A)

100nm

(B)

(C)

++++++

+*

*

b

+

+

(100

) (002

)(1

01)

(102

)

(110

)

(103

)(1

12) (2

01) (0

04)

(222

)

(111

)(1

11)

(200

)

(220

)

(311

)(2

22)

a

2θ (degrees)30 50 70 806040

Inte

nsity

++++++

+*

*

b

+

+

(100

) (002

)(1

01)

(102

)

(110

)

(103

)(1

12) (2

01) (0

04)

(222

)

(111

)(1

11)

(200

)

(220

)

(311

)(2

22)

a

2θ (degrees)30 50 70 806040

Inte

nsity

(D)

C

20nm

Wavelength (nm)300 500 700 900

Abso

rban

ce

0

0.2

0.4

0.6A BA Bba

ab

C

20nm

Wavelength (nm)300 500 700 900

Abso

rban

ce

0

0.2

0.4

0.6A BA Bba

ab

20 nm

(A)

100nm

(B)

100nm

(B)

(C)

++++++

+*

*

b

+

+

(100

) (002

)(1

01)

(102

)

(110

)

(103

)(1

12) (2

01) (0

04)

(222

)

(111

)(1

11)

(200

)

(220

)

(311

)(2

22)

a

2θ (degrees)30 50 70 806040

Inte

nsity

++++++

+*

*

b

+

+

(100

) (002

)(1

01)

(102

)

(110

)

(103

)(1

12) (2

01) (0

04)

(222

)

(111

)(1

11)

(200

)

(220

)

(311

)(2

22)

a

2θ (degrees)30 50 70 806040

Inte

nsity

(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.

Lish

a, An

shup

, T. P

rade

ep, G

old B

ull. 4

2 (20

09) 1

44

200 400 6000.00

0.05

0.10

(viii)(ix)

(ii)

(i)

Wavelength (nm)

Abso

rban

ce(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 et

al (u

npub

lishe

d)

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

0 40 80 0 40 80

log(

1+X)

02

468

02

468

02

468

02

468

AgNO3R2 = 0.98

RodR2 = 0.9689

SphereR2 = 0.9878

TriangleR2 = 1

(B)

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

0 40 80 0 40 80

log(

1+X)

02

468

02

468

02

468

02

468

AgNO3R2 = 0.98

RodR2 = 0.9689

SphereR2 = 0.9878

TriangleR2 = 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.

Elec

higue

rra, A

. Cam

acho

, K. H

olt, J

.B. K

ouri,

J.T. R

amire

z, M.

J. Ya

cama

n, Na

notec

hnolo

gy 16

(200

5) 23

46

Raman Shift (cm-1)300 500 700 900

SERS

Inte

nsity

(a)

Raman Shift (cm-1)300 500 700 900

SERS

Inte

nsity

PVPBTHDTMDA

(b)

SERS

Inte

nsity

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

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 fe

d

c

b

a

Abso

rban

ce

Wavelength (nm) Wavelength (nm)400 600 800

Abso

rban

ce

0

0.1

0.2

0.3

ab

c

def

(c)(C)

Colorimetric detection of chlorpyrifos using the gold nanoparticle-Na2SO4 system

Au a+Na2SO4 b+50 ppb CP

b+100 ppb CP

b+500 ppb CP

b+1 ppmCP

M. M

ulvihi

ll, A.

Tao

, K. B

enjau

thrit,

J. Ar

nold,

P. Y

ang,

Ange

w. C

hem.

Int. E

d. 47

(200

8) 64

56

K.P.

Lish

a, An

shup

, T. P

rade

ep, J

. Env

iron.

Sci.

Healt

h B. (

in pr

ess)

Pollutants Harmless products

CO2

TiO2

HCs

Polluted water Purified water

As adsorption

Magnetic Fe3O4 nanopartilcles

Purification by circulation

Magnetic clays for oil cleanupAntibody taggingMagnetic hyperthermia

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

(A) Fe3O4 solution (B) After application of magnetic field (C) TEM imagesof the nanocrystals

Low-

Field

Magn

etic S

epar

ation

of M

onod

isper

seFe

3O4 n

anoc

rystal

s, C.

T. Y

avuz

, J. T

. May

o, W

W

Yu, A

Pra

kash

, JC

Falkn

er, S

Yea

n, L C

ong,

HJ S

hipley

, A K

an, M

Tom

son,

D Na

telso

n, VL

Colv

in,

Scien

ce, 2

006,

314,

964

Product Name Nanomaterial utilized Contaminants removal Adsorption capacity Product life Product priceAquaguard Gold Nova, Eureka Forbes Limited

Silver nanoparticles supported on alumina

Pesticides and halogenated organics - 6000 liters $50

Adsorbia Titania nanoparticlesArsenic 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 $50

Nanoceram, Argonide Electropositive alumina nanofibers on a glass filter substrate

Disinfection, natural organic matter, turbidity, salt, radioactivity, heavy metals - - $3-10 per sq m2,

$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 problemsAll inclusive solutionsLocal manufactureCommunity involvement – NGOs

What OECD can do?

A white paper on available technologiesAct as a link between those who need the technology and those who have the solutionsConduct 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 CouncilWell-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