Celebrating 50 years

Affordable clean water using nanotechnology T. Pradeep Department of Chemistry and Sophisticated Analytical Instrument Facility Indian Institute of Technology Madras Chennai 600 036, http://www.dstuns.iitm.ac.in/pradeep_research_group.php

It is the poor who drive our society.

Potential Environmental Benefits of Nanotechnology: Fostering safe innovation-led growth OECD July 15-17, 2009 Chapter by T. Pradeep and Anshup

O 99.84 pm 2 nm 104.45O HH Gas hydrates to ozone chemistry Water - prosperity, health, serenity, beauty, artistry, purity …..

Claude Monet, Waterlilies, 1906 Oil on Canvas, The Art Institute of Chicago Water - “the vehicle of nature" ("vetturale di natura”) – Leonardo Da Vinci

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

Leonardo Leonardo Old Man with Water Studies, c. 1513 Machine for raising water Water and civilizations

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

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

Mohenjodaro – the great bath Nitrates Fluoride Asbestos ……

Microbes Heavy metals Chemicals, pesticides

Water filtration: various media

hof.povray.org/River.html Important milestones in the history of water purification (1800-2007)

Year Milestone 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 Last globally big invention in 1935 Discovery of synthetic ion exchange resin (Adams, Holmes) water purification 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)

Credits to several governments, organizations and individuals, we have moved ahead. Now, the journey of “pure water for all” calls for next big innovation. Source: Multiple sources from internet 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)

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 Review of major contaminants in drinking water Major Sources of Permissible Affected countries Population at risk Health effects Remarks pollutant origin limits (estimates) Pesticides - Farming, DDT: 1 ppb US, Kenya, Egypt, Poisoning: 28 million Cancer, cardiovascular/ Pesticide effluents, Carbofuran: India, European Union, agricultural workers in reproductive/ contamination in soft home use 40ppb Africa, China, developing countries. neurological disorders, drinks, Union Carbide Simazine: 4 ppb Australia ~18,000 deaths Liver/kidney problems Bhopal tragedy (India)

Halogenated Chlorination, CCl4: 5 ppb Japan, Central Asia, ~180 million people in -CCl4: High toxicity to - 25 million pounds organics effluents, TCE: 5 ppb Arabian Peninsula, US consume liver and kidney, TCE were released in home TTHMs: 80 ppb Sweden, Poland, chloraminated water carcinogenic. TCE: the U.S. environment insecticide Germany, USA, Egypt, Lung/liver tumor by manufacturing China plants in 1995

Fluoride - Geological 2 ppm Asia, Mexico, 62 million (India) - Dental and skeletal A union of 1,200 origin, Australia, Argentina, fluorosis, Muscle fibre scientists, doctors and mineral Africa, New Zealand regeneration, nervous lawyers announced weathering, system malfunction opposition to water coal mining fluoridation (1999)

Arsenic - Geological 10 ppb , India, 65 million (Asia) High blood pressure, - Death rate: 1 in 100 origin China, Pakistan, glucosuria, people (Conc: 50 ppb) Nepal, Myanmar, hyperpigmentation, and 10 in 100 people Vietnam keratoses, cancer (Conc: 500 ppb) Mercury - Industrial 2 ppb Indonesia, China, ~630,000 infants are Neurotoxicant, tremors, - ~30% of the mercury pollution, Africa, Philippines, born with high Hg respiratory failure, in US comes from dental filling, Japan, Kazakhstan, content in the blood gastrointestinal failures, abroad e.g. China - Food (fish) USA, Brazil, Australia, every year (EPA) and kidney damage Unilever plant, Taiwan, EU Kodaikanal. Minamata, Niigata, River Nura.

Lead - Old piping 15 ppb Egypt, EU, USA, >300,000 US children Delays in physical or - Incidence of Gout due lines, mineral Thailand, China, and 65% of Shanghai mental development, to leaded wine and weathering, Cambodia children have high lead Kidney problems, high rum- Use of lead in paint concentration blood pressure paints and discharge in environment Review of major drinking water contaminants, their health impacts and a few associated eventsmultiple sources from internet Quantum of Fluoride Contamination Fluoride contamination: Indian Scenario

• 25 million people are suffering from fluorosis and 62 million are at the risk of fluorosis 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 How much of our environment is polluted by cadmium? Ground water (1995-96) (Source: PCB) Location State Cd (mg/l) Fresh water (Source: PCB) Coastal water (Source: PCB) Min Max Conc. Location Conc Location (mg/l) Korba Madhya Pradesh NT 0.01 (μg/l) Off Bombay 80.00 (1980) Bellandur Lake, Bangalore 0.70 Singrauli Utter Pradesh NT 0.01 Gobindpur Punjab NT 0.08 Point Calimere 0.1-0.6 (1991) , West 0.68 Parwanoo Himachal Pradesh NT 0.062 Cuddalore 2-27 (1994) Saptamukhi River, West 0.85 Bengal Kala Amb Himachal Pradesh NT 0.150 Madras Coast 1.4 (1987) Hugli River, 0.59 Pali Rajasthan 0.005 0.224 River Coovum 0.98 (1991) Subernarekha River, West 0.47 Jodhpur Rajasthan <0.005 0.042 Parangipettai Coast 2-25 (1994) Bengal Nazafgarh Delhi NT 0.013 East Coast NT-2.9 (1999)

• 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 Affordable Drinking Water Purifier – Market needs

Unsolved technology problems

Mercury contamination, Minamata, Microbial contamination, Zimbabwe, 2009 Japan, 1956

Pesticide contamination, Kerala, 2001 Fluoride contamination, India, 2003 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 AQ-4000 E-5199 SY-2300 Deluxe Smart Water H-54 DWS1000 Plus FM- Faucet Filter Pitcher Number 38465 GXSV10C 3000 Filter Retail $124.99 $420.00 $159.99 $149.99 $139.99 $149.99 $349.95 $49.95 $34.95 $24.95 Price Replacem $48.00 / $120.00 / $50.39 / $49.00 / $60.00 / 540 $79.95 / 750 $79.99 / 625 $20.00 / 100 $20.00 / 100 $7.70 / 30 ent Cost 500 Gal. 1250 Gal. 500 Gal. 500 Gal. Gal. Gal. Gal. Gal. Gal. Gal. & Capacity Cost per 9.6 ¢ Per 9.6 ¢ Per 10¢ Per 9.8¢ Per 11¢ Per Gal. 10.6¢ Per 13¢ Per Gal. 20¢ Per 20¢ Per Gal. 25¢ Per gallon Gal. Gal. Gal. Gal. Gal. Gal. 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 $172.99 $420.00 $210.38 $198.99 $199.99 $229.90 $349.95 $229.95 $214.95 $273.91 1000 gals. Our goals of a socially relevant science has largelyAffordability failed due of Technologyto our inability to serve people at bottom-of-the-pyramid Products from Product Average cost Income Annual Household # of Functions Eureka Forbes Ltd Price per liter (10 yrs) Segment Income ($) Households INR 7590 Turbidity, Chlorine, Bacteria, Virus, Aquaguard Classic Rs 0.61 Community <$ 2,000 132,249 ($ 168) Odor $2,000-$4,500 53,276 Aquaguard Nova and I- INR 7690 Turbidity, Chlorine, Bacteria, Virus, Low-Budget Rs 0.70 $4,500-$11,000 13,183 Nova ($ 171) Odor $11,000-$22,000 3,212 Aquaguard Gold INR 9,590 Turbidity, Chlorine, Bacteria, Rs 0.94 Nova ($ 213) Virus, Odor, Pesticides $22,000-$44,000 1,122 INR 15,500 TDS, Taste, Heavy metals, High-Budget $44,000-$111,000 454 Aquaguard RO - - Rs 1.86 $111,000-$222,000 103 ($ 345) pesticides, F /NO3 INR 2,000 $222,000 52 Aquasure 4-in-1 Turbidity, Chlorine, Bacteria, Virus Rs 0.33 ($ 45) Source: www.ncaer.org - Year 2005 INR 650 Aquasure on TapTurbidity, Chlorine, Bacteria, Virus Rs 0.12 ($ 15) Boiling - Bacteria, Virus Rs 0.18 INR 250 Bottled Water - Rs 2.0 ($ 6) Reference: Eureka Forbes Ltd, Bangalore (2008) • 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 An object for the nanotechnology - nanomaterials

5 nm

20 nm

2 nm A B

20 15 C 10

5 Height (nm) 0 0 100 200 300 400 Distance (nm)

0.6

0.4 I

II

Absorbance 0.2

III 0.0 100400 nmD 600 800 1000 Wavelength (nm)

200 nm Range of nanostructured materials

Y. Xia et. al., Adv. Mater 2002, 14,11,833

http://www.nano- http://www.physics.upenn.edu/~dr PJF Harris et. al., J. Phys.: Condens. lab.com/imagegallery.html ndic/group/graphene.html Matter 20 (2008) 362201 Nanocatalysis

STM image of MoS2 nanoflakes. From, Nanotechnology 14, pp. 385-389 (2003) 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 Future of water purification: An enigma with some pointers 25

21 20 Candidate contaminant list Contaminants regulated by EPA 15 15 13

10 9 9 10 7 66 6 5 5 4 4 4 4 5 5 3 2 Number of contaminants 1 11111111 1 2 0 rqponml k j i hgf edcba l k j i h f d b Label for contaminants (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

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 Future of water purification: Shrinking limits for allowed concentration of contaminants in water

200 200 Lead Arsenic 150

100 100 100

50 50 50 50 Concentration (in ppb) (in Concentration

10 0

1950 1960 1970 Year 1980 1990 2000 Changes in maximum allowable concentration for lead and arsenic in drinking water, based on WHO advisory 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 Permissible contamination reacheslimits ofdetection

Permissible contamination 10 12 Time molecules Organics

Pesticides Tansel and Nagarajan, Advances in Environmental Research 8, 2004, 411–415 Traditional methods (activated carbon, membranes)

Nanomaterials

Metals, oxides, clays, dendrimers

Plakas, Karabelas, Wintgens and Melin, Journal of Membrane Science 284, 2006, 291–300 Illustration of metal adsorption on nanoparticle surface (ZVI surface)

TEM image of Fe nanoparticle and Cartoon representation of chemistry at Fe nanoparticle, Iron Nanoparticles: the Core-Shell Structure and Unique XPS wide-scan survey of iron nanoparticles after exposure to a metal Properties for Ni(II) Sequestration, Xiao-qin Li and Wei-xian Zhang, Langmuir salt containing solution, Sequestration of Metal Cations with Zerovalent 2006, 4638-4642 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

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 Metal adsorption on nanoparticle surface (ZVI surface)

(b) Ni2+ 0 (c) Sorption Ni Ni(II) Ni(II) )

4 2.4 24 hrs Reduction 1.8 3 hrs Ni(0) 1.2 1 hr

Counts (X 10 Fe(0) FeOOH 0.6 15 min 0 Ni2+ + 2e- → Ni Eº = -0.25 V 859 856 853 850 3+ - Binding energy (eV) Fe → Fe + 3 e Eº = 0.44 V (L) HR-XPS survey on the Ni 2p3/2 of iron nanoparticles (R) a conceptual model for nickel deposition on iron nanoparticles After 24 hrs Ag@citrate-Hg(OAc) Hg(II) 2 Hg 4f 7/2 Hg 4f 5/2

101.4

Hg(0)

Counts 100.2 104.2 100 ppm 50 ppm 105.4 10 ppm 7 ppm

96 99 102 105 108 111 Binding Energy (eV)

Bootharaju et al. Unpublished Metal oxide and MWNT assembly based membrane filtration X.B. Ke, H.Y. Zhu, X.P. G Zhu,X.P. Ke,H.Y. X.B. Adv. Mater. 19(2007)785 Adv. Mater.

1 μm u, H.Y.Zhu, X.P. Gao, ao, J.W.Liu,Z.F.Zheng, Wang, H.J. Zhao, J. Shi, (a) (b) 1 μm

(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

X.B. H.W. Li Ke, Z.F. Zheng, L.X. Zhang, N.P. Xu, H. 112 (2008) 5000. B Chem. J. Phys. Ratinac, K.R. and permeate water (inset). Filtration efficiency=96.8% Pt wire Ajayan, N.Koratkar, Z.Wang, L.Ci,C (a) 0 sec 15 sec 30 sec (b) hen, S.Nayak,P.M. Nano Lett.7(2007)697 45 sec 60 sec 80 sec J.P. Noworyta, Nature J.P.

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

G. Hummer, J.C. Rasaih, Rasaih, G. Hummer, J.C. 414 (2001) 188. 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) Noble metal nanomaterials: Novel chemistry for water purification

Halogenated organics & pesticides

a 0.4 b

0.2

Absorbance Gold With nanoparticles Endosulfan 0.0 400 600 800 1000

Wavelength(nm)

+

+ +

- -

- +

+ + - - - +

-

+ +

+ Bacteria & virus Heavy metals 0.6

0.4

0.2 Gold With mercury AbsorbanceAbsorbance nanoparticles 0 300 500 700 900 Wavelength (nm) 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

Color of gold nanoparticles with endosulfan Example

200 100 2 0 Endosulfan Endosulfan concentration in ppm Color changes with pesticide concentration Pesticide removal Good response at lower concentrations Indian Patent granted Down to 0.1 ppm International patent filed Adsorbed pesticides can be removed from solution Technology 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

0.5 0.4 a a c d e 0.4 b 0.3 t

0.3

0.2 0.2

Absorbance c Absorbance 0.1Endosulfan Chlorpyrifos0.1 b Malathion

0.0 0.0 400 500 600 700 800 900 1000 1100 400 500 600 700 800 900 1000 1100 Wavelength(nm) Wavelength (nm)

UV-visible spectra of gold nanoparticles showing the detection Time dependent adsorption of endosulfan on gold nanoparticles of endosulfan at different concentrations (b.2, c.10, d.100 and and the corresponding spectral changes (a-t). The shifts in the e. 250 ppm). Inset (A-D): Color changes of the solutions plasmon band are due to the binding of the pesticide on the corresponding to traces a, b, c and d, respectively. nanoparticle surface. Supported nanoparticles for pesticide removal

Activated alumina globules (A) and gold (B) and silver (C) nanoparticles coated on the same.

Silver nanoparticles coated on activated alumina (neutral) powder These can be made in ton quantities. 4 cm Nanoparticle loaded alumina can remove pesticides

0.15 0.15 a 0.16 a 0.12 b 0.12 b c c 0.10 0.08 0.10 0.08

Absorbance 0.04

Absorbance Absorbance 0.04 0.05 0.05 r 0.00 0.00 Absorbance 0 100 200 300 400 500 600 Absorbance p 0 100 200 300 400 500 600 Time (minutes) q Time (minutes) s 0.00

0.00 300 400 500 600 700 800 300 400 500 600 700 800 Wavelength (nm) Wavelength (nm)

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. Other scientific tests conducted confirm the complete removal of commonly occurring pesticides from water

A b 100 a 0.10 80 a

60

40 % Transmittance% (Arb.Units) 0.05 20 3000 2500 2000 1500 1000 500 70 B b

60 Absorbance Absorbance a 50 0.00 b-e 40

30

400 600 800 1000 (Arb.Units) Transmittance % 3000 2500 2000 1500 1000 500 Wavelength (nm) W avenumber ( cm -1 ) Absorption spectra showing the complete removal of Infrared spectra of the free pesticides (a) and that pesticides when contaminated water was passed adsorbed on the nanoparticle surfaces (b) chlorpyrifos through a column of the nanomaterial. Trace a is the (A) and malathion (B). spectrum of the parent pesticide solution, b-e after passing through the nanoparticle-loaded column, in repeated experiments. Product of this reaction is amorphous carbon Noble metal nanoparticles: removal of pesticides from water

a [V] [mV] 1.5 b CPCPCP A B 2.142.142.14 400 0.5 2.9332.9332.933 200 1.0

0 2.52.52.5 3.3073.3073.307 0.5 0.0 -200 rr. Sci. 84 (2003) 1560 Absorbance o -400 p 0.0 -0.5 -600 400 600 800 1000

Wavelength (nm) 0 2 4 0 2 4 (a) Time (min) Time (min) Variation of the UV-visible absorption Gas chromatogram of chlorpyrifos solution (L) and after spectrum of silver nanoparticles upon treatment with silver nanoparticles (R) A.S. Nair, T. Pradeep, Cu T. Pradeep, A.S. Nair, the addition of CCl4 m, V.R. Rajeev June 2007

(b) A.S. Nair, R.T. To Kumar, C. Subramaniam, T. Pradeep, Cosmos 3, (2007) 103 (L) Silver nanoparticles coated on activated alumina (R) Photograph of a pesticide filter device using supported nanoparticles (WQA certified) Product is marketed now Cartridges are recovered after use A pesticide test kit has been developed > 25 ppb Noble metal nanoparticles: removal of heavy metals from water

(A) (C) 0.6 (D) a aABb (111)(111)(111)(111) b a

0.4 (200)(200)(200)(200) (220) (220) (220) (220) (311)(311)(311)(311)

20 nm (222)(222)(222)(222)

IntensityIntensityIntensityIntensity b (B) 0.2 (002)(002)(002)(002) AbsorbanceAbsorbanceAbsorbanceAbsorbance 20nm (004)(004)(004)(004) (100)(100)(100)(100) (101) (101) (101) (101)

+ + (201) (201) (201) (201)

* (111)(111)(111)(111) (222)(222)(222)(222) +

C (110) (110) (110) (110) (112)(112)(112)(112) (103)(103)(103)(103) 0 + (102)(102)(102)(102) + + ++ +* eep, Gold Bull. 42 (2009) 144 eep, Gold Bull. 300 500 700 900 100nm 30 40 50 60 70 80 Wavelength (nm) 2θ (degrees) (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. T. Prad Lisha, Anshup, Noble metal nanoparticles: removal of heavy metals from water

(a) 0.10 (i) (b) (b)

0.05 (ii)

Absorbance (viii) (ix) 0.00 200 400 600 5 μm Wavelength (nm) (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

T. Pradeep et al (unpublished) (a) (b) (c)

2 μm Ag|Si Hg|Si (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). Noble metal nanoparticles: removal of bacteria (E. coli) from water (B) (A) AgNO3 Rod 8 8 a b a b AgNO3 Rod 6 R2 = 0.98 6 R2 = 0.9689 4 4 uri, J.T. Ramirez, uri, J.T. Ramirez, c d c d 2 2 0 0 0 40 80 0 40 80 a b a b 8 Sphere 8 Triangle log(1+X)log(1+X) 2 2 ho, K. Holt, J.B. Ko J.B. Holt, K. ho, 6 R = 0.9878 6 R = 1 4 4 c d c d 2 2 0 0 0 40 80 0 40 80 Sphere Triangle Concentration of silver (µg) (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

J.R. Morones, J.L. Elechiguerra, A. CamacJ.R. Morones, 16 (2005) 2346 Nanotechnology M.J. Yacaman, silver nanoparticles in agar plates. Noble metal nanomaterials: detection of toxic species

(a) (b) (c) AsIII + AsV PVP AsV BT HDT MDA SERS Intensity SERS Intensity SERS Intensity K. Benjauthrit, J. K. Benjauthrit, 300 500 700 900 300 500 700 900 500 600 700 800 900 1000 -1 -1 Raman Shift (cm ) Raman Shift (cm ) Raman Shift (cm-1) 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: M. Mulvihill, A. Tao, M. Mulvihill, A. Int. Ed. Arnold, P. Yang, Angew. Chem. 47 (2008) 6456 mercaptodecanoic acid. (c) SERS-based speciation of arsenate and arsenite ions (18 ppb)

(A) 0.30.3 f b def f a b cdc e f e e Au a+Na SO d 2 4 b+50 ppb b+100 ppb b+500 ppb b+1 ppm d CP CP CP CP 0.20.2

adeep, J. Environ. Sci. Sci. adeep, J. Environ. (B) a b c c 0.10.1 Absorbance

Absorbance bb aa 0.00 400 500 600 700 800 900 (c)(C) 400 600 800 50 nm 50 nm 50 nm WavelenWavelengthgth (nm) (nm ) K.P. Anshup, T. Pr Lisha, Health B. (in press) Colorimetric detection of chlorpyrifos using the gold nanoparticle-Na2SO4 system Pollutants Harmless products

TiO2

CO2 HCs Polluted water Purified water As adsorption

Magnetic Fe3O4 nanopartilcles

Purification by circulation T. Yavuz, J. T.Mayo, WW ipley, A Kan, M Tomson, D Natelson, VL Colvin,

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

Monodisperse Fe3O4 nanocrystals, C. (A) Fe3O4 solution (B) After application of magnetic field (C) TEM images of the nanocrystals

Magnetic clays for oil cleanup Antibody tagging Yu, A Prakash, JC Falkner, S Yean, L Cong, HJ Sh Science, 2006, 314, 964 Low-Field Magnetic Separation of Magnetic hyperthermia

Commercial interests in drinking water purification

Product Name Nanomaterial utilized Contaminants removal Adsorption capacity Product life Product price Aquaguard Gold Nova, Eureka Silver nanoparticles supported on Pesticides and halogenated organics - 6000 liters $50 Forbes Limited alumina Adsorbia Titania nanoparticles 12-15 gm As(V) and 3- Arsenic and disinfection 4 gm As(III) per kg of -- adsorbent AD33, Adedge Technologies, Inc. Iron oxide nanoparticles Heavy metals including arsenic, lead, - 3,800-11,400 $50 chromium, zinc, copper Nanoceram, Argonide Electropositive alumina nanofibers Disinfection, natural organic matter, $3-10 per sq m2, on a glass filter substrate turbidity, salt, radioactivity, heavy metals -- $75 per filter

ArsenX, SolmeteX, Inc. Hydrous iron oxide nanoparticles on Arsenic, vanadium, chromium, uranium 38 mg of Arsenic per $0.07-0.20 per polymer substrate gm of adsorbent 1,000 liters - (amortized due to reusability) Nanopore, Nanovation AG Membrane filters based on ceramic Disinfection nanopowder supported on alumina ---

Examples of a few nanotechnology-based products in drinking water purification market (compiled from multiple sources on the World Wide Web) 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

Nano Mission, Department of Science and Technology World Gold Council Well-meaning individuals Thank you all Transmission Confocal Raman Microscope Scanning Electron Microscope Electron Microscope

MALDI TOF MS

QTrap MS XPS Ultramicrotome

Nanoscience and Nanotechnology Initiative of the DST