This talk is not about the usual stuff.

Future Directions of Advanced Materials Research, Shimla April 16-19, 2008

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0 100 200 300 4000

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15

20

Heigh

t (nm

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Distance (nm)

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Sajanlal and Pradeep, Adv. Mater., 20 (2008) 980

NanoflowersSajanlalal and Pradeep - unpublish

Shibu et al. Adv. Mater., (2008) In Press.

Particle crystals

New chemistry

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, factory put up

J. Environ. Monitoring. 2003

Nanoparticles of silver disappear in a chemical reaction.

Inauguration

Pesticide removal from drinking water

Product testing stage

Time (minutes) Time (minutes)

A B

T. Pradeep pradeep@iitm.ac.in

2 nm

oking at the social realities through the nanA limited view

Nanotechnology Applications: Solutions for Improving Water Quality, Mamadou Diallo, Jeremiah Duncann, Nora Savage and Anita Street (Eds.), US Environmental Protection Agency, William Andrew Publishing, 2008

Water is the biggest business in India.Bottled water – Rs. 2400 CrStorage filters – Rs. 1000 CrPiped water –

Still water is not there for the poor

Gas hydrates to ozone chemistry

Claude Monet, Waterlilies, 1906Oil on Canvas, The Art Institute of Chicago

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

hof.povray.org/River.html

Microbes Heavy metals Chemicals,pesticides

NitratesFluorideAsbestos……

Water filtration: various media

Per

mis

sibl

e c

onta

min

atio

n

Time

Contamination reaches molecular limits

This is where technologies fail

Regulated chemicals as in USEPA regulations for 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

Classification of USEPA regulated contaminants

It is very much clear from the regulations of USEPA, that halogenated organics are going to dominate the future regulative activity

Reaching molecular limits

- 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 metallic in nature

Going into the future, a few trends are clearly visible

- Continued focus of USEPA regulatory activities on various otherhalogenated organics found in drinking water- Many of these organics are extremely stable in environment, andhence chemistry of novel materials is the need- Continuing with the history, the concentration limits for these organics is expected to be in sub-ppb range

RDX

Prometon

Terbacil

Acetochlor

Metolachlor

Diazinon

So, what are our problems?Images collected from arsenic, fluoride and pesticide affected areas in India

For 8-month old Sainaba to 18-year old Ramaswamy, science is yet to deliver its benefits

Pictures from the web

Why nanotechnology?

Problems:

SalinityMicrobesOrganicsFluorideArsenicMercuryCadmium….

Available solutions do not take care of the problemscompletely.

Drinking water solutions require new approaches to make clean water affordable.

Problems are indeed serious.Case study: Metal pollution – cadmium in the environment

Source: ICDASource: ICDA

Global Cadmium Production

(tonnes/year) and % (Source: ICDA/USGS)

Ni-Cdbattery

Pigment Stabilizer Plating Other

16,200 2,000 300 1,400 100 20,000

81% 10% 1.5% 7% 0.5% 100%

Total

Case Study

How much of our environment is polluted by cadmium?

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

• The above figures are just 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

Location Conc(mg/l)

Bellandur Lake, Bangalore 0.70

Matla River, West Bengal 0.68

Saptamukhi River, West Bengal

0.85

Hugli River, West Bengal 0.59

Subernarekha River, West Bengal

0.47

Fresh water (Source: PCB)Cd (mg/l)Location State

Min Max

Korba Madhya Pradesh NT 0.01

Singrauli Utter Pradesh NT 0.01

Gobindpur Punjab NT 0.08

Parwanoo Himachal Pradesh NT 0.062

Kala Amb Himachal Pradesh NT 0.150

Pali Rajasthan 0.005 0.224

Jodhpur Rajasthan <0.005 0.042

Nazafgarh Delhi NT 0.013

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

Coastal water (Source: PCB)

Case Study

Only two solutions exist for environmental detoxification: Find an alternative eco-friendly way or full recycle and implementation at global scale. Possible in next 5-10 years?

?

Drinking water norms for metal is very stringent and is reachingmolecular limits

Illustration of metal adsorption on nanoparticle 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

Case Study

Landscape of commercial technologies

Chlorination

UV treatment

Ion Exchange

Distillation

Activated Carbon

Reverse Osmosis

Membrane Separation

Ion specific adsorption

- Broad operating range vis-à-vis contaminants

- High initial investment & high maintenance

- High surface area and effective against VOC & Chlorine

- Not effective against microbes, inorganic ions, metals

- High surface area and effective against VOC & Chlorine

- Not effective against microbes, inorganic ions, metals

- Highly effective against high TDS water and removes ions

- High cost, brine and pre-treatment

Generalist Approach

Specialist Approach

- Strong oxidant against microbes. Fast kinetics. Cheap.

- Problem of chlorination by-products. Taste.

- High surface area and effective against VOC & Chlorine

- Not effective against microbes, inorganic ions, metals

- High surface area and effective against VOC & Chlorine

- Not for suspended solids, microbes. Bacterial growth. High costs.

- Highly effective against microbial contamination and high efficiency

- High cost & discharge removal

New technologies are coming – but water is still not affordable.

We have failed to deliver quality water to people at bottom-of-the-pyramid

• 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

Universal purifier: Remove suspended particles, pesticides, microbes, metals and anionsZero electricityMinimum maintenance and low-cost of annual replacement (< INR 400/-)

• Indeed, early signs of success with nanotechnology shows the promise

Affordability of Technology

Solutions available for organics, fluoride, arsenic, mercury, lead, microbes,..Need to integrate technologies.

Nano is opening newer avenues for solving many of our unsolved problems in drinking water

Introduction to Nano approach

Need for affordability and purity

Era of novel discoveries

Science, Selling and Society

Motivation

- 62 million affected by fluoride, 35 million affected by arsenic, 30 million affected by water-borne diseases

- 134 million residing in rural India, with minimum access to safe water, health amenities and electricity

- Many of the drinking water problems are genuinely Indian problems and need an Indian solution

- Nano has opened new doors to solve problems in completely novel ways e.g. degradation of highly resistant molecules

- Nano based chemistry being surface kinetics driven, can completely change the properties of existing materials for purification

- Any new breakthrough using nano will provide an impetus to India’s technology leadership

- Need for collaboration of Science with commercial parties

- No more pure technology development, lets create new products for Indian consumers

- Newer paradigms in serving the society can be opened through solving age-old problems

E. F. Schumacher

Pure water can be affordable…..

A few interesting words of wisdom• If there is magic on this planet, it is contained in water. Loran Eisely, The Immense

Journey, 1957

• Life originated in the sea, and about eighty percent of it is still there. Isaac Asimov, Isaac Asimov's Book of Science and Nature Quotations, 1988

• Water, water, everywhere, nor any drop to drink. The Rime of the Ancient Mariner by Samuel Taylor Coleridge, 1798

• If we could ever competitively, at a cheap rate, get fresh water from saltwater, this would be in the long-range interests of humanity which could really dwarf any other scientific accomplishments. John F. Kennedy, Ex-US President, 1961

• High quality water is more than the dream of conservationists, more than a political slogan; high quality water, in the right quantity at the right place at the right time, is essential to health, recreation and economic growth. Edmund S. Muskie, Ex- U.S. Senator, 1966

• Water has become a highly precious resource. There are some places where a barrel of water costs more than a barrel of oil. Lloyd Axworthy, Foreign Minister of Canada, 1999

US Geological Survey http://ct.water.usgs.gov/education/morewater.htm

Water Opinions

A end-note on what Nano-research for the drinking water

Possible Outcomes

International advantages

- Demonstration of technology advancement for India

- World’s first few nano based technology for water purification

- Easy product adaptability to both developed and developing countries

National

- As mentioned, these are our problems and hence we need our solution

- Development of a platform for future targeting of other national problems of interest

Society

- A solution created for the Indian masses

- Society can reap the benefit from overall economic growth of nation and realize the power of technology

- Visibility for efforts of Indian scientific community

Fluoride has been finding its way in drinking water due to severe groundwater contamination• Groundwater contributes ~0.6% of total water resources on the planet, primarily

because seawater is a surface water body– It caters to 80% of total drinking water and 50% of agricultural water requirement

• Contamination of Indian drinking water is attributed primarily to increasing industrialization

– It indeed is not a cause for fluoride contamination since it was first detected in 1937– Fluorine is highly reactive and is found naturally as CaF2. It is an essential constituent

in minerals like topaz, fluorite, fluorapatite, cryolite, phosphorite, theorapatite etc. – The endemic fluorosis in India is largely of hydro-geochemical origin– Low calcium and high bicarbonate alkalinity favor high fluoride content in groundwater– Water with high fluoride content is generally soft, has high pH and contains large

amount of silica• Fluoride in low quantity is an essential component for normal mineralization of bones

and formation of dental enamel and hence is added to dental pastes– The safe limit of fluoride in drinking water is 1.0 mg/L– The fluoride concentrations has been observed to be more than 50.0 mg/L– Drinking water contributes almost 75-90% of fluoride found in human body

• Fluoride creates problem in human body due to high electro-negativity and corresponding interactions with calcium found in bones and teeth

– Dental Fluorosis: teeth discoloration, mottling and pitting of the teeth– Skeletal Fluorosis: Stiffened and brittle bones and joints, osteoporosis– Other forms: Muscle fibre regeneration, low hemoglobin, nervous system malfunction

Need for Affordability and Purity

Fluoride has been known a global contaminant, affecting over 24 countries in the world including India, US, China, Japan, Africa

• Total population coverage in affected districts = 356.5 million• Actual Population suffering from fluorosis = 62 million

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

Interesting reads• MN Baker, MJ Taras (1981), The quest for pure water: The history of the twentieth

century, vol. 1-2, Denver: AWWA • Alice Outwater (1996), Water: A natural history, Basic Books, New York• Rachel Carson (1962), Silent Spring, Houghton Mifflin• GT Miller (2004), Sustaining the Earth - 6th ed., Thompson Learning, Inc.• Theo Colborn, Dianne Dumanoski, John Peterson Myers (1997), Our Stolen

Future, Plume/Penguin Group

In research, the horizon recedes as we advance, and is no nearer at sixty than it was at twenty. As the power of endurance weakens with age, the urgency of the pursuit grows more intense... And research is always incomplete.

Does Nano hold a promise for environmental detoxification?

Case Study

Nano-based Chemistry

- Surface adsorption on metal oxide nanoparticles (e.g. MnO2, Fe2O3)- Lose a proton (XOH → H+ + XO-) or gain a proton (XOH + H+ → XOH2

+)

- Replacement of H+ by other metals symbolizes metal adsorption whereas ligand adsorption is represented by the substitution of hydroxyl groups

- The greater the ionic potential of the cation, the smaller the adsorption of M+

- Nature of the metal species is determined by the pH of the solution. pH = 2, 98% Hg = Hg2+, 65% Fe = Fe3+

- Difficulties: Optimum pH for different metals, changes in the pH of treated water, Recovery

- Surface adsorption on metal nanoparticles (e.g. Fe)

- Fe3+ + 3e- → Fe0 E0 = -0.037V Fe2+ + 2e- → Fe0 E0 = -0.447 V

- Fe NP has shown good potential for absorbing reduced metals

-The heterogeneous nature of galvanic reaction means increase in surface area translates to increased reaction sites

-Difficulties: Surface passivation, adsorption happens on oxide surface rather than zerovalent surface

History of Reverse Osmosis Technology1748 - Abbe Noilett discovered the phenomenon of osmosis in natural membranes1855 - Adolph Fick a German mathematician and physics genius created a cellulose nitrate (nitrocellulose) membrane as the first synthetic membrane1866 - Thomas Graham a British physical chemist first used the term dialysis.

1869 - The first synthetic polymer studied & produced commercially by Schoenbein

1907 - Bechold first introduced the term ultrafiltration

1927 - Sartorius Company first made membranes commercially available

1934 - Research on electrodialysis done by G. R. Elder

1950 - Gerald Hassler introduces the first concept of membrane desalination

1958 - C. E. Reid and E. J. Breton showed that cellulose acetate was an effective membrane material for water desalination1960 - Sidney Loeb and Srinivasa Sourirajan developed the first practical membranes for a water desalting process called reverse osmosis1960 - H. K. Londsdale develops thin film composite type membranes

1963 - H. I. Mahon developed the first capillary (Hollow Fiber) membranes

1965 - The world's first commercial RO plant was built in Coalinga, CA

1977 - John Cadotte patents thin film composite membrane under government granthttp://www.reverseosmosisinfo.com/history-of-reverse-osmosis.html

Evolution of water purification

Society had realised the importance of water treatment long ago

Evolution of water purification

• Records from as early as 2000 BC prove that Early Sanskrit writings outlined methods for purifying water.

– Methods comprised of boiling, hot metal heating, crude sand or charcoal filters (Sushruta Samhita)

• First signs of Ion-exchange technology is visible in Holy Bible (Book of Exodus, Chapter 15, verses 22-25)

– The use of cellulose from the tree for ionic exchange

• Ancient civilizations started the use of aqueducts for creating efficient water transport networks (Greek, Roman and American civilizations)

– The end of civilizations marked the end of innovations and thus began the Dark ages

• Around 400 BC, Hippocrates, the father of medicine, linked the importance of water to overall well-being of the human health

– Designed “Hippocratic sleeve” for trapping sediments in water after boiling

Mohenjodaro – the great bath

Early 1600’s saw the beginning of scientific investigations for water purificationSir Francis Bacon tested the idea of sand filter for desalination in 1627

In mid-1600s, Anton van Leeuwenhoek, father of microscopy, developed microscope reaching up to 270x

Suddenly science got empowered to see minute objects in water

In mid-1800s, first governmental regulation on public drinking water supply came in existence

In 1804, the first citywide, municipal water treatment plant was installed in Paisley, Scotland using Robert Thom's sand-filter technology. It was replicated in England in 1827Metropolis Water Act of 1852 was formulated in England to ensure filtered drinking water.John Snow proved presence of bacteria to outbreak of cholera in London (1854) leading to discovery of chlorine (Humphrey Davy, 1810) as disinfectant. Other pioneers: Robert Koch and Joseph Lister.

The history of water purification technologies (after 20th century)

• In 1908, chlorine in the form of dissolved sodium hypochlorite—was first applied to a municipal supply in Jersey City, N.J.

– In 1974, potentially carcinogenic byproducts of disinfection with chlorine were identified in drinking water.

• UV was first used in municipal supplies between 1916 and 1928– Inactivates resistant Cryptosporidium cysts, perhaps much more economically

• Thompson and Way furthered the understanding of ion exchange in mid-1800s– Adams and Holmes (1935) discovered the synthetic organic ion exchange resins

• In the late 1940s, research began on water desalination technologies– UCLA scientists, Samuel Yuster, Sidney Loeb and Srinivasa Sourirajan, produced

a functional synthetic RO membrane from cellulose acetate polymer (1959).

• World's first commercial RO plant launched in 1965– This was the beginning of advent of membrane based systems for water

purification– In early 1980’s, first Composite Polyamide membrane based RO was developed

• Capacitive deionization

Evolution of water purification

The cost of RO solutions has seen a dramatic fall since the discovery, but high cost are likely to remain

Costs analysis of Reverse Osmosis PlantsEconomic and technical assessment of desalination technologies, Fawzi Banat, Geneva, June07

Evolution of water purification