Nanotechnology applications for clean water

edited by Nora savage Office of Research and Development, US Environmental Protection Agencyand in alphabetical order Mamadou Diallo Materials and process simulation center, Division of

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applicatioNs for cleaN Water

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series editor: Jeremy ramsden

Professor of Nanotechnology Microsystems and Nanotechnology Centre, Department of Materials

Cranfield University, United Kingdom

the aim of this book series is to disseminate the latest developments in small scale technologies with a particular emphasis on accessible and practical content these books will appeal to engineers from industry, academia and government sectors.

for more information about the book series and new book proposals please contact the publisher, Dr Nigel hollingworth at nhollingworth@williamandrew.com.

http://www.williamandrew.com/MNt

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edited by Nora savage Office of Research and Development, US Environmental Protection Agency

and (in alphabetical order) Mamadou Diallo Materials and process simulation center, Division of chemistry and chemical engineering, california institute of technology

Jeremiah Duncan Nanoscale Science and Engineering Center, University of Wisconsin-Madison

anita street Office of Research and Development, US Environmental Protection Agency

and richard sustich Center of Advanced Materials for the Purification of Water with Systems,

University of Illinois at Urbana-Champaign

N o r w i c h , N Y, U S AapplicatioNs for

cleaN Water

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including photocopying, recording, or by any information storage and retrieval system, without sion in writing from the publisher.

permis-ISBN: 978-0-8155-1578-4

Library of Congress Cataloging-in-Publication Data

Nanotechnology applications for clean water / edited by Nora savage [et al.]

p cm (Micro & nano technologies)

includes bibliographical references and index

Printed in the United States of America

This book is printed on acid-free paper

eNviroNMeNTally FrieNdly

this book has been printed digitally because this process does not use any plates, ink, chemicals,

or press solutions that are harmful to the environment The paper used in this book has a 30% recycled content.

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Introduction: Water Puriﬁ cation in the Twenty-First

Century—Challenges and Opportunities xxxi

Richard C Sustich, Mark Shannon, and Brian Pianfetti

Part 1 Drinking Water 1

1 Nanometallic Particles for Oligodynamic Microbial Disinfection 3

Gordon Nangmenyi and James Economy

2 Nanostructured Visible-Light Photocatalysts for

Water Purification 17

Qi Li, Pinggui Wu, and Jian Ku Shang

3 Nanostructured Titanium Oxide Film- and Membrane-Based

Photocatalysis for Water Treatment 39

Hyeok Choi, Souhail R Al-Abed, and Dionysios D Dionysiou

4 Nanotechnology-Based Membranes for Water Purification 47

Eric M.V Hoek and Asim K Ghosh

5 Multifunctional Nanomaterial-Enabled Membranes for

Water Treatment 59

Volodymyr V Tarabara

6 Nanofluidic Carbon Nanotube Membranes: Applications for

Water Purification and Desalination 77

Olgica Bakajin, Aleksandr Noy, Francesco Fornasiero,

Costas P Grigoropoulos, Jason K Holt, Jung Bin In, Sangil Kim,and Hyung Gyu Park

7 Design of Advanced Membranes and Substrates for

Water Purification and Desalination 95

James Economy, Jinwen Wang, and Chaoyi Ba

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8 Customization and Multistage Nanofiltration Applications for

Potable Water, Treatment, and Reuse 107

Curtis D Roth, Saik Choon Poh, and Diem X Vuong

9 Commercialization of Nanotechnology for Removal of

Heavy Metals in Drinking Water 115

10 U.S.–Israel Workshop on Nanotechnology for Water Purification 131

Richard C Sustich

Part 2 Treatment and Reuse 141

11 Water Treatment by Dendrimer-Enhanced Filtration:

Principles and Applications 143

Mamadou S Diallo

12 Nanotechnology-Enabled Water Disinfection and Microbial Control:

Merits and Limitations 157

Shaily Mahendra, Qilin Li, Delina Y Lyon,

Lena Brunet and Pedro J.J Alvarez

13 Possible Applications of Fullerene Nanomaterials in

Water Treatment and Reuse 167

So-Ryong Chae, Ernest M Hotze, and Mark R Wiesner

14 Nanomaterials-Enhanced Electrically Switched Ion Exchange

Process for Water Treatment 179

Yuehe Lin, Daiwon Choi, Jun Wang, and Jagan Bontha

15 Detection and Extraction of Pesticides from Drinking

Water Using Nanotechnologies 191

T Pradeep and Anshup

Part 3 Remediation 213

16 Nanotechnology for Contaminated Subsurface Remediation:

Possibilities and Challenges 215

Denis M O’Carroll

17 Nanostructured Materials for Improving Water Quality:

Potentials and Risks 233

Marcells A Omole, Isaac K’Owino, and Omowunmi A Sadik

18 Physicochemistry of Polyelectrolyte Coatings that Increase

Stability, Mobility, and Contaminant Specificity of Reactive Nanoparticles Used for Groundwater Remediation 249

Tanapon Phenrat and Gregory V Lowry

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19 Heterogeneous Catalytic Reduction for Water Purification:

Nanoscale Effects on Catalytic Activity, Selectivity, and Sustainability 269

Timothy J Strathmann, Charles J Werth, and John R Shapley

20 Stabilization of Zero-Valent Iron Nanoparticles for

Enhanced In Situ Destruction of Chlorinated Solvents in Soils and Groundwater 281

Feng He, Dongye Zhao, and Chris Roberts

21 Enhanced Dechlorination of Trichloroethylene by

Membrane-Supported Iron and Bimetallic Nanoparticles 293

S M C Ritchie

22 Synthesis of Nanostructured Bimetallic Particles in

Polyligand-Functionalized Membranes for Remediation Applications 311

Jian Xu, Leonidas Bachas, and Dibakar Bhattacharyya

23 Magnesium-Based Corrosion Nano-Cells for Reductive

Transformation of Contaminants 337

Shirish Agarwal, Souhail R Al-Abed, and Dionysios D Dionysiou

24 Water Decontamination Using Iron and Iron Oxide Nanoparticles 347

Kimberly M Cross, Yunfeng Lu, Tonghua Zheng, Jingjing Zhan,

Gary McPherson, and Vijay John

25 Reducing Leachability and Bioaccessibility of Toxic Metals in

Soils, Sediments, and Solid/Hazardous Wastes Using Stabilized Nanoparticles 365

Yinhui Xu, Ruiqiang Liu, and Dongye Zhao

Part 4 Sensors 375

26 Nanomaterial-Based Biosensors for Detection of Pesticides and

Explosives 377

Jun Wang and Yuehe Lin

27 Advanced Nanosensors for Environmental Monitoring 391

Omowunmi A Sadik

28 A Colorimetric Approach to the Detection of Trace Heavy

Metal Ions Using Nanostructured Signaling Materials 417

Yukiko Takahashi and Toshishige M Suzuki

29 Functional Nucleic Acid-Directed Assembly of Nanomaterials and

Their Applications as Colorimetric and Fluorescent Sensors for Trace Contaminants in Water 427

Debapriya Mazumdar, Juewen Liu, and Yi Lu

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Part 5 Societal Issues 447

Introduction to Societal Issues: The Responsible Development of

Nanotechnology for Water 449

Jeremiah S Duncan, Nora Savage, and Anita Street

30 Nanotechnology in Water: Societal, Ethical, and Environmental

Considerations 453

Anita Street, Jeremiah S Duncan, and Nora Savage

31 Competition for Water 463

Jeremiah S Duncan, Nora Savage, and Anita Street

32 A Framework for Using Nanotechnology To Improve

David Rejeski and Evan S Michelson

34 Nanoscience and Water: Public Engagement At and Below

the Surface 521

David M Berube

35 How Can Nanotechnologies Fulfill the Needs of Developing

Countries? 535

David J Grimshaw, Lawrence D Gudza, and Jack Stilgoe

36 Challenges to Implementing Nanotechnology Solutions to Water

Issues in Africa 551

Mbhuti Hlophe and Thembela Hillie

37 Life Cycle Inventory of Semiconductor Cadmium Selenide

Quantum Dots for Environmental Applications 561

Hatice Sengül and Thomas L Theis

Part 6 Outlook 583

38 Nanotechnology Solutions for Improving Water Quality 585

Mamadou S Diallo, Jeremiah S Duncan, Nora Savage,

Anita Street, and Richard Sustich

Index 589

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National Risk Management Research Laboratory

U.S Environmental Protection Agency

Cincinnati, OH, USA

Department of Chemistry and Sophisticated Analytical Instrument Facility

Indian Institute of Technology Madras

Chennai, India

Chaoyi Ba

Center of Advanced Materials for the Puriﬁ cation of Water with Systems

Department of Materials Science and Engineering

Urbana, IL, USA

Molecular Biophysics and Functional Nanostructures Group

Chemistry, Materials, Earth, and Life Sciences Directorate

Lawrence Livermore National Laboratory

Livermore, CA, USA

David M Berube

Professor of Communication and Coordinator of PCOST

North Carolina State University

Raleigh, NC, USA

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Paciﬁ c Northwest National Laboratory

Richland, WA, USA

National Risk Management Research Laboratory

Cincinnati, OH, USA

Daiwon Choi

Richland, WA, USA

Kimberly M Cross

Department of Chemical & Biomolecular Engineering

University of California at Los Angeles

Los Angeles, CA, USA

Mamadou S Diallo

Materials and Process Simulation Center

Division of Chemistry and Chemical Engineering

California Institute of Technology

Pasadena, CA, USA

Department of Civil Engineering

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Urbana, IL, USA

Lisa Farmen

Crystal Clear Technologies, Inc

Portland, OR, USA

Livermore, CA, USA

Department of Mechanical Engineering

University of California at Berkeley

Berkeley, CA, USA

David J Grimshaw

Practical Action

Bourton-on-Dunsmore, Rugby, UK

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Lawrence D Gudza

Practical Action

Bourton-on-Dunsmore, Rugby, UK

Feng He

Environmental Engineering Program

Auburn University

Auburn, AL, USA

Thembela Hillie

Council for Scientiﬁ c and Industrial Research

Pretoria, South Africa

Mbhuti Hlophe

Department of Chemistry

North-West University (Maﬁ keng Campus)

Mmabatho, South Africa

Eric M.V Hoek

California NanoSystems Institute

University of California

Water Technology Research Center

University of California

Jason K Holt

Livermore, CA, USA

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Department of Mechanical Engineering

University of California at Berkeley

Berkeley, CA, USA

Center for Advanced Sensors & Environmental Monitoring

State University of New York at Binghamton

Binghamton, NY, USA

Sangil Kim

Livermore, CA, USA

Qi Li

Urbana, IL, USA

Richland, WA, USA

Ruiqiang Liu

Urbana, IL, USA

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Gregory V Lowry

Department of Civil and Environmental Engineering

Carnegie Mellon University

Pitsburgh, PA, USA

Yunfeng Lu

Department of Chemical & Biomolecular Engineering

University of California at Los Angeles

Yi Lu

Urbana, IL, USA

Robert F Wagner Graduate School of Public Service

New York University

New York, NY, USA

Gordon Nangmenyi

Urbana, IL, USA

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Aleksandr Noy

Livermore, CA, USA

Denis M O’Carroll

Department Civil & Environmental Engineering

The University of Western Ontario

London, Ontario, Canada

Marcells A Omole

Binghamton, NY, USA

Hyung Gyu Park

Livermore, CA, USA

Tanapon Phenrat

Carnegie Mellon University

Pitsburgh, PA, USA

Brian Pianfetti

Department of Mechanical Science and Engineering

Urbana, IL, USA

Saik Choon Poh

CH2MHILL

T Pradeep

Department of Chemistry and Sophisticated Analytical Instrument Facility

Indian Institute of Technology Madras

Chennai, India

David Rejeski

Project on Emerging Nanotechnologies

Woodrow Wilson International Center for Scholars

Washington, DC, USA

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National Science Foundation

Arlington, VA, USA

Binghamton, NY, USA

Nora Savage

Oﬃ ce of Research and Development

Washington, DC, USA

Hatice Sengül

Institute for Environmental Science and Policy

Department of Civil and Materials Engineering

University of Illinois at Chicago

Chicago, IL, USA

Jian Ku Shang

Urbana, IL, USA

Mark Shannon

Urbana, IL, USA

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John R Shapley

Urbana, IL, USA

Anita Street

Oﬃ ce of Research and Development

Washington, DC, USA

(Environmental Scientist and Program Analyst, at U.S Department of Energy,

Energy and Enviromental Security Directorate, Oﬃ ce of Intelligence and

Counterintelligence, Washington, DC, USA, as of November 2008)

Richard C Sustich

Urbana, IL, USA

Toshishige M Suzuki

Research Center for Compact Chemical Processes

National Institute for Advanced Industrial Science and Technology (AIST)

Sendai, Miyagi, Japan

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Yukiko Takahashi

Nagaoka University of Technology

Nagaoka, Niigata, Japan

Volodymyr V Tarabara

Michigan State University

East Lansing, MI, USA

Thomas L Theis

Institute for Environmental Science and Policy

Department of Civil and Materials Engineering

University of Illinois at Chicago

Chicago, IL, USA

Diem X Vuong

DXV Water Technologies, LLC

Tustin, CA, USA

Jinwen Wang

Urbana, IL, USA

Jun Wang

Richland, WA, USA

Urbana, IL, USA

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Pinggui Wu

Urbana, IL, USA

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The Potential of Nanotechnology for

Clean Water Resources

Current global development is not sustainable over the long term Every

major ecosystem is under threat at diﬀ erent timescales, impacting water, food,

energy, biodiversity, and mineral resources—all exacerbated by the population

growth and climate change It has been estimated that about 1.1 billion people

are now at risk from a lack of clean water and about 35 percent of people in

the developing world die from water-related problems If in 2008 only a few

countries have a water supply deﬁ cit, it is estimated that by 2025, based on

the extrapolation of current data, more than half of world countries will be in

a similar crisis

Nanotechnology solutions are essential because the abiotic and biotic

impurities most diﬃ cult to separate in water are in the nanoscale range By its

control at the foundation of matter, nanoscale science and engineering may

bring breakthrough technologies not otherwise possible for improving water

quality Also, at the other end, nanotechnology may oﬀ er eﬃ cient manufacturing

with less resources and waste to reduce pollution at its site of origin

Water ﬁ ltration and desalinization have been relatively less-explored topics

in nanotechnology, but there has been a new trend in this direction in the last

few years This is an area of importance for life, it is of signiﬁ cant interest to

the productive engine and the public at large, and there are many stakeholders

That said, research and development have been lagging behind advances in

areas such as electronics, materials science, and pharmaceuticals, which have

relatively shorter term returns Infrastructure for water resources requires a

relatively larger investment for a longer period of time and the diverse potential

sponsoring sources need to be better coordinated So we have to make a

sustained eﬀ ort to bring the production of nanotechnology in water ﬁ ltration

to the same level as that of other nanotechnology applications Here it seems

that governments and global governance should have an important role in

addition to stimulating imaginative research

Science and technology are turbulent dynamic ﬁ elds where coherent structures

appear and break down Nanotechnology promises to dominate the landscape

for many of these ﬁ elds over the next several decades Research and development

at this scale can answer major challenges for society, from improved comprehension

of nature and increased productivity in manufacturing, to molecular medicine

and extending the limits for sustainable development

Nanotechnology is developing at a fast pace With over $6 billion in

nanotechnology R&D annual investment worldwide, industry exceeded

govern-ment R&D funding by about $1 billion (the total annual R&D investgovern-ment is

about $11 billion) in 2007 Nanotechnology R&D has changed its research

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focus, typical outcomes, the domains of industrial relevance, its public

perception, and its governance since 2000 when it was suggested as a

twenty-ﬁ rst century key technology The rudimentary capabilities of nanotechnology

today for systematic control and manufacture at the nanoscale are envisioned

to evolve signiﬁ cantly after 2010 because of the integration of new theories, tools,

and system architectures now only existing as concepts There is an increased

realization that sustainable use of earth resources is a main target for

nano-technology that may rally strong international support Internationally shared

R&D priorities in conservation of earth resources are expected to expand in

water ﬁ ltration and desalinization in the coming years Already international

organizations such as UNESCO and OECD have placed this topic on their

agenda

Nanotechnology has become a domain of intense international and scientiﬁ c

collaboration and industrial competition that has expanded after about 2005

to clean water technology Research is now preparing a new generation of

products and processes These changes are accelerated, global, and are

inte-grated with other emerging technologies Because of this, it is essential to have

a good governance approach at national and international levels, so we can

take advantage of the immense promise of nanotechnology for advancing

human development and can diminish possible negative implications One

main goal of global governance should be use of nanotechnology for water

ﬁ ltration and desalinization The investment in nanotechnology applications

for clean water processing in the world was estimated at about $1.5 billion in

2007 But the face of nanotechnology is evolving and so the interest and

available expertise for using nanotechnology for clean water is moving up on

the list of priorities

This book provides a unique perspective, mainly from academic and

govern-ment research laboratories, on basic research issues regarding drinking water,

water treatment and reuse, remediation, and sensors In addition several

contri-butions address broader societal concerns and challenges for future research

The reader may ﬁ nd of interest ideas from leading experts at institutions such

as the Center of Advanced Materials for the Puriﬁ cation of Water with Systems

(University of Illinois at Urbana-Champaign), University of California at Los

Angeles Water Technology Center, Carnegie Mellon University, Rice University,

University of Kentucky, The University of Western Ontario, Paciﬁ c Northwest

National Laboratory (U.S.), National Institute for Advanced Industrial Science

and Technology (Japan), Munasinghe Institute for Development (Sri Lanka),

and Woodrow Wilson Center for Scholars in this volume Researchers and

practitioners may ﬁ nd in this volume key challenges and proposed solutions

regarding clean water resources The potential of nanotechnology to signiﬁ cantly

advance the availability of clean water is well documented The presentations

may crystallize new research and education programs

U.S National Science Foundation and U.S National Nanotechnology Initiative

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It is by now presumably well known that nanotechnology has the potential

to contribute novel solutions to an enormous range of problems currently

facing the world Ensuring the availability of potable water ranks as one of the

more important and urgent of those problems, and nanotechnology is clearly a

candidate for helping to solve it Furthermore, nanotechnology is speciﬁ cally

appropriate because the problems of water puriﬁ cation, from the viewpoint of

what needs to be removed from contaminated water, crucially mostly involve

the nanoscale

Water is a ubiquitous facilitator of civilization, de facto essential for almost

everything that we do, ranging from maintaining human health, to ensuring

plant growth, and enabling the transport of merchandise Therefore, it is not

too surprising that water sciences constitute an extremely multidisciplinary

ﬁ eld This book collects the expertise of specialists in many areas to give an

overview of all the major parts of the ﬁ eld, notably in the preparation of

potable water (Parts 1 and 2), remediation at the ecosystem level (Part 3),

sensing of the impurities in water (Part 4), which is obviously essential for

both the preparation of potable water and environmental remediation, and

ﬁ nally societal issues (Part 5) The reader should note that this book is written

from a distinctly U.S viewpoint It should therefore be of especial interest for

practitioners and researchers from the rest of the world, for it provides a

comprehensive overview of the current state-of-the-art of clean water

tech-nologies in the United States

Although it is the technology chapters to which readers will turn to, to

acquaint themselves with leading practices and anticipated new technologies in

a country that has a strong and well developed water treatment industry, Part

5, dealing with societal issues, will also generate interest Perhaps no economic

good of humankind is more culturally charged than water, and I think it is fair

to say that the real value of Part 5 is to encourage debate and discussion in an

area that has hitherto received relatively scant attention, in comparison with

the impressive body of work on the practical technologies of clean water

treatment Impending scarcities of clean water are likely to be too pressing

to be solved solely by the application of new technology, which makes it all the

more timely to raise the plethora of societal issues that impinge upon the

matter Technologists typically have a tendency to somewhat neglect these

aspects, yet they are becoming more and more important for the successful

implementation of any new technology with the potential to solve a pressing

challenge As an example, the estimation of daily human water consumption,

which is obviously important when planning resource allocation, has a strong

cultural aspect, for it depends upon dietary customs People accustomed to a

diet rich in fresh fruit and vegetables, which consist mostly of water (by mass),

may have a requirement for drinking liquid water that is virtually nil, but this

is obviously not true if biscuits and lean meat are the main sources of nutrition

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Another welcome topic in Part 5 is that of water availability in the developing

world, not least because it is there that some of the deﬁ ciencies of the present

arrangements, and the discrepancies between supply and demand, are the

most glaring The issues in Africa and elsewhere are notoriously complex,

and their discussion should not be eschewed merely because they are

controversial

Given the necessarily ﬁ nite length of this book, some hugely complex issues

are simply raised in the hope that others will be suﬃ ciently inspired to think

about possible responses One of the most signiﬁ cant questions of this nature

relates to the indeed striking observation that “water is intrinsically

undervalued” (Chapter 31) Why indeed has the market economy so singularly

failed to have resolved that issue, which is responsible for so many of the

current diﬃ culties? One hopes that economists will be encouraged to address

the matter!

One of the most interesting chapters, in the sense of presaging a new approach

to the ﬁ eld, is the very last one in the book, on a life cycle inventory of

cad-mium selenide nanoparticles In the excitement over possible nanotechnology

solutions, a complete overview of this kind is often neglected; however eﬀ ective

such nanoparticles may be for environmental applications, for example, the

extreme toxicity of their precursors (and maybe of the particles as well, if

ingested by humans) makes them very undesirable Technologies such as these

have a strong potential to “bite back,” and this chapter reminds us that one

of the most eﬀ ective ways of ensuring the availability of potable water for all

of mankind is to avoid polluting it in the ﬁ rst place

Jeremy RamsdenCranﬁ eld UniversityUnited KingdomNovember 2008

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Nanotechnology Applications for Clean Water

Introduction

The U.S National Nanotechnology Initiative (NNI) deﬁ nes “nanoscience”

as “research to discover new behaviors and properties of materials with

dimensions at the nanoscale, which ranges roughly from 1 to 100 nanometers

(nm).” A key objective of nanotechnology is to develop materials, devices, and

systems with fundamentally diﬀ erent properties by exploiting the unique

properties of molecular and supramolecular systems at the nanoscale In recent

years, research in this ﬁ eld has grown exponentially as scientists and engineers

continue to develop nanomaterials with unique and enhanced properties

Nearly every ﬁ eld of science has been aﬀ ected by the tools and ideas of

nanotechnology, and breakthroughs have been made in computing, medicine,

sensing, energy production, and environmental protection Recent advances

strongly suggest that many of the current problems involving water quality

can be addressed and potentially resolved using nanosorbents, nanocatalysts,

bioactive nanoparticles, nanostructured catalytic membranes, and nanoparticle

enhanced ﬁ ltration, among other products and processes resulting from the

development of nanotechnology This book discusses the use of nanotechnology

to improve water quality and the societal implications therein that may aﬀ ect

acceptance or widespread applications Its primary objectives are to:

provide a summary of the state of the ﬁ eld to interested scientists,

1

engineers, and policymakers;

consider the technological advances in the context of society’s

2

interests and needs;

identify grand challenges and directions for future research in

3

the ﬁ eld

Organization and Content

This book consists of contributions from 90 scientists Following the foreword

by Mihail Roco (U.S National Science Foundation) and preface, the introduction

discusses the global water needs and puriﬁ cation challenges facing the world

The remainder of the book is comprised of 38 chapters, divided into ﬁ ve parts

Part 1 focuses on “Drinking Water.” Here, we highlight ten contributions

including: (i) ten chapters on the developments of novel nanostructured

membranes and nanoﬁ ltration processes for water puriﬁ cation and

desali-nation, and (ii) a summary of the discussion and recommendations of the joint

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U.S.–Israel Workshop on Nanotechnology for Water Puriﬁ cation held in March

2006 Part 2 is devoted to “Treatment and Reuse.” Here, we feature ﬁ ve

contributions including: (i) three chapters on the applications of dendritic and

fullerene nanomaterials to water treatment, reuse, and disinfection, and (ii) a

case study of the detection and recovery of pesticides from contaminated water

using nanotechnology Part 3 focuses on “Remediation.” All ten chapters in

this part discuss the use of redox active and catalytic nanoparticles in the

remediation of groundwater and surface water contaminated by chlorinated

organic compounds (e.g., trichloroethylene), oxyanions (e.g., nitrate), and toxic

metal ions (e.g., chromium) Part 4 is devoted to “Sensors.” Here, we highlight

four contributions including three chapters on the use of nanomaterials as

ﬂ uorescent and colorimetric sensors for detecting toxic metal ions in water

Part 5 is devoted to “Societal Issues.” The eight chapters of this section tackle

a broad range of issues including (i) the competition for water, (ii) the

responsible development of nanotechnology for water, and (iii) the challenges

(including governance and public acceptance) of implementing nanotechnology

solutions to address critical water supply and quality problems, especially in

developing countries Finally, Part 6 concludes with the editors’ own outlook

at the prospects for the future of nanotechnology in the water quality arena

We hope this book will inspire scientists, engineers, and students to continue

to create new solutions to address the ever-increasing global demand for clean

and potable water

Disclaimer

The views expressed on the parts of editors Nora Savage and Anita Street

do not reﬂ ect the views of the Environmental Protection Agency, and no

oﬃ cial endorsement should be inferred

Nora Savage, Mamadou Diallo, Jeremiah Duncan,

Anita Street, and Richard Sustich

November 2008

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The edition of this special issue was an exciting and challenging endeavor

We really enjoyed putting it together We thank the authors and reviewers for

their hard and high-quality work We thank the publisher, Nigel Hollingworth

(William Andrew Inc.), for the invitation and opportunity to edit this book

Mamadou Diallo thanks his wife Laura for her patience and constant support

throughout this project He also thanks the National Science Foundation (NSF

Grant NIRT CBET-0506951) and the U.S Environmental Protection Agency

(NCER STAR Grant R829626) for funding his research on the application of

dendrimer nanotechnology to water puriﬁ cation Partial funding for Dr Diallo’s

research program was also provided by the Department of Energy (Cooperative

Agreement EW15254), the W M Keck Foundation, and the National Water

Research Institute (Research Project Agreement No 05-TT-004) Jeremiah

Duncan thanks the National Science Foundation (NSF Grant DMR 0425880),

which provides primary funding for the Nanoscale Science and Engineering

Center at the University of Wisconsin at Madison, and his wife, Kimberly, for

her enduring patience and support Nora Savage thanks colleagues, friends,

and family who provided support during a pivotal time during the completion

of this project Anita Street thanks her coeditors, family, friends, and colleagues

for their patience and support without which this project would not have been

possible Richard Sustich thanks the National Science Foundation (NSF Grant

CTS-0120978), which provides primary funding for the Center of Advanced

Materials for the Puriﬁ cation of Water with Systems, his countless professional

colleagues at the U.S Environmental Protection Agency and the National

Advisory Council for Environmental Policy and Technology and the

Metropolitan Water Reclamation District of Greater Chicago, and his children,

Kyle, Kerri, and Keith, for allowing the time and distraction to complete this

project

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Savage et al (eds.), Nanotechnology Applications for Clean Water, xxxi–xl,

in the Twenty-First Century—Challenges

and Opportunities

Richard C Sustich , Mark Shannon , and Brian Pianfetti

Center of Advanced Materials for Purification of Water with Systems,

University of Illinois at Urbana-Champaign, Urbana, IL, USA

I.1 Current Water Issues

Ensuring the availability of clean, abundant fresh water for human use is

among the most pressing issues facing the United States and the world, as

depicted in Fig I.1 [ 1 ] Nature framed the issues by stating, “More than one

billion people in the world lack access to clean water, and things are getting

worse Over the next two decades, the average supply of water per person will

drop by a third, possibly condemning millions of people to an avoidable

premature death” [ 2 ] In the United States as in the rest of the world, water

has a broad impact on health, food, energy, and economy While it might seem

that the United States is blessed with abundant fresh water, regional scarcities

and competing demands leave little room for growth Recent environmental

catastrophes (e.g., the Indian Ocean Tsunami (2004), Hurricane Katrina)

demonstrate how fragile our municipal water supplies and infrastructure are,

as well as those needed to provide energy and irrigation for food Environmental

stress resulting from climate change and population growth and migration is

expected to increase over next two decades ( Fig I.2 ) [ 3 ]

The challenges facing water production for human use in the United States

and elsewhere are not fully deﬁ ned nor do their solutions ﬁ t into a neat box

Rather, they are a complex and interrelated set of problems requiring a suite

of individual, local, regional, national, and even international solutions

incorporating an integrated information base and eﬃ cient, cost-eﬀ ective, and

reliable analytical and treatment technologies Aquifers throughout the United

States (e.g., Ogallala, Mahomet) and around the world (e.g., Central China)

are suﬀ ering from declining water levels, saltwater intrusion, contamination

from surface waters, and inadequately replenished fresh groundwater Major

rivers and watersheds are also being overdrawn (e.g., Colorado River), while

return ﬂ ows are contributing to downstream nutrient loading and salinity

problems (e.g., Gulf of Mexico) Lakes and wetlands are also experiencing

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increased salting in many areas In much of the developed world, this is an

opportune time to address water problems, because aging water infrastructure

will need to be upgraded over the next 40 years Estimated costs through 2019

for infrastructure replacement in the United States alone are estimated to

range from $485 billion to $896 billion (excluding operations and maintenance

using current technologies) [ 4 ] As staggering as this sum appears, it is most

likely only a fraction of the true cost needed to create new water supplies,

which is an additional cost Although conservation has allowed substantive

reduction in per capita water use in developed countries over the past 30 years,

conservation alone cannot halt the demand an expanding global population

and developing economies place on water Redistributing current supplies to

meet future needs carries additional costs in infrastructure (pumps, canals,

and pipelines) and energy This approach leads to collateral economic losses

from rationing and lost opportunities to expand energy, agriculture, and

business activities Such confounding challenges, however, also oﬀ er substantial

opportunities to create new water-related businesses, products, and industries

that can be marketed all over the world, which is, as a whole, experiencing

similar issues and problems There is little doubt that satisfying humankind’s

demand for water in a sustainable manner requires visionary new approaches

to management and conservation of water resources augmented by new

technologies capable of dramatically reducing the cost of supplying clean fresh

water—technologies that can best be derived from tightly coupled basic and

applied research

Figure I.1 Populations without access to safe drinking water (From The World’s Water

of Island Press, Washington, D.C.)

Percent of population without access

No data 1% - 25%

26% - 50%

51% - 75%

76% - 100%

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Figure I.2 Relative change in demand per discharge (From Vörösmarty et al., Science

289: 284 (July 14, 2000) Reprinted with permission from AAAS.)

Climate Change Only

(Sc1)

Population Change

Only (Sc2)

Population and Climate Change (Sc2)

<0.8 0.8-1.2

>1.2 ΣDIA/Q Scenario

ΣDIA/Q Base

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There is a nearly one-to-one correlation throughout the world between

national economic output and per capita water use The United States has the

highest Gross National Product (GNP) and the highest fresh water usage in

the world at approximately 2,000 m 3 per person per year, whereas sub-Saharan

Africa has the lowest GNP and water usage (approximately 100 m 3 per person

per year) The two notable exceptions to this correlation—Singapore and

Israel—are important lessons for developed and developing nations alike Both

have signiﬁ cant freshwater resource issues and both spend a much larger

percentage of their GNP for water production and water research than the

United States and other developed nations The Congressional Budget Oﬃ ce

estimated in 2001 that average annual costs for U.S water systems, including

operations and maintenance, over the period 2000–2019 will range from $70.7

billion to $98 billion (in 2001 dollars) Cumulatively, costs for the 20-year period

are expected to range from $1.4 trillion to $1.96 trillion (in 2001 dollars) [ 5 ]

These estimates assume that water resources and water availability remain

stable at current levels Under this scenario, many American households could

see water rates increase by an order of magnitude, bringing residential water

bills on a par with energy bills Energy production (coal/gas/nuclear generation,

mining, and reﬁ ning) presently accounts for the largest fresh water withdrawals

in the United States, and while more than 97 percent of water withdrawn for

energy production is returned to the environment, this return does not replenish

highest quality sourcewaters and aquifers [ 6 ] With projected increasing energy

demands, consumptive water loss for energy production and detrimental water

quality impacts could increase dramatically with increased production of

alternative biofuels [ 7 ] (Chapter 31, “Competition for Water,” includes a

discussion of the impacts of the production of biofuels on water availability

and competition.) As increases in acreage and irrigation are needed for the

production of biofuels, further dramatic increases in demand will strain existing

water supplies and new water sources will be needed If lack of water limits

growth in new energy supplies, every aspect of the U.S and global economy

will be aﬀ ected, increasing costs to the consumer Clearly, the costs to upgrade

infrastructure and create new supplies likely cannot be met without revolutionary

improvements in the science and technology of water puriﬁ cation

On top of the impending supply crisis, the United States faces a host of

water quality issues that demand improved treatment methods to resolve

These problems include toxic organic compounds, heavy metals, and pathogens,

many of which pose health risks at very low (less than parts per million) levels

The ability to robustly sense and remove low-level contaminants can better

protect the health of Americans, but at what cost? The costs of contaminant

removal and residuals management currently make regulating many trace

contaminants prohibitive However, if we can selectively and eﬃ ciently remove

trace toxic and problematic contaminants, through ﬁ ltering or transformation,

without removing a large amount of nontoxic and even beneﬁ cial constituents,

the costs can be greatly reduced We also need to improve disinfection to

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inactivate pathogens that are resistant to current methods and to prevent

introduced or emerging pathogens from causing large-scale harm, all without

creating disinfection byproducts that are themselves highly toxic Improved

disinfection will also help the rest of the world, where estimated annual

water-related mortality rates range from 2.2 to 12 million [ 8 ] There is a clear and

urgent need for new, more eﬀ ective methods to purify water for the people of

the United States and the world

I.2 Water Puriﬁ cation: Impacts and Opportunities

I.2.1 Water–Environment Nexus

While ensuring adequate supplies of potable water for human use must

continue to be a research priority, the environmental impacts of increasing human

water consumption will also demand attention Portions of the midwestern,

southeastern, and southwestern United States are already seeing increased

water stress The U.S Environmental Protection Agency now has more than

90 contaminants on their Candidate Contaminate List that are, or soon need

to be, addressed by water treatment plants Additionally, relatively few aquifers

in the United States have been adequately surveyed to determine actual

available groundwater reserves Better research on the availability, detection of

contaminants, and strategies for remediation can increase utilization of

currently available sources as well as facilitate development of new water

sources such as brackish aquifers

I.2.2 Water–Energy Nexus

In 2000, thermoelectric power production in the United States accounted

for 132.4 billion gallons per day, or 39 percent, of all fresh water withdrawals,

and 3 billion gallons, or 3 percent, of fresh water consumption [ 6 ] By 2030,

generating capacity is expected to expand by 22 percent, and whereas projected

changes in withdrawals vary from –21 to +6 percent depending on the new

generation and cooling technology deployed, fresh water consumption is

expected to increase by 28–49 percent [ 9 ] Concurrent eﬀ orts to reduce

dependence on imported oil through new fuels such as biomass, syngas, and

hydrogen are expected to expand the overall water footprint of the energy

sector even further Of the nation’s 104 nuclear reactors, 24 are located in

areas experiencing severe drought, such as the southeastern United States, and

face potential shutdowns due to water scarcity and concerns over environmental

impacts [ 10 ] New sources of water, and new puriﬁ cation technologies to

enhance water reuse, will be needed to keep pace with energy demands

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I.2.3 Water–Food Nexus

Food production is even more closely linked to the availability of water than

energy production Although most Americans know that they are recommended

to consume one gallon of water per day for proper hydration, most generally

don’t recognize the amount of water used to produce the food that they

consume (water footprint) Across the United States, 41 percent of all water

withdrawn, 139,189 million gallons per day, is used for irrigation and livestock [ 6 ]

Additionally, 85 percent, or 84,956 million gallons of water per day, is lost (not

returned) to the local water source by irrigation and livestock production [ 6 ]

New technologies that can dramatically enhance agricultural water conservation

and increase the recovery and reuse of irrigation runoﬀ and livestock wastewater

could have the largest impact on future water availability

I.2.4 Water–Health Nexus

Lack of access to potable water is a leading cause of death worldwide

Dehydration, diarrheal diseases, contaminated source waters, waterborne

pathogens, water needed for food production (starvation), and water for

sanitation are just some of the factors that impact health Around the world,

1.1 billion people (17 percent) lack access to improved water and 2.4 billion

(42 percent) lack access to improved sanitation Every year 1.8 million people

die from diarrheal diseases (including cholera) Between 28 and 35 million

people in the Bangalore region in India suﬀ er from arsenic poisoning from their

water supplies Every day, an estimated 3,900 children die from water-related

disease or poor hygiene [ 11 ] As our water sources become more stressed, these

numbers could increase substantially The water–health nexus is crucial for the

survival of humanity Creating better disinfection and puriﬁ cation technologies

could signiﬁ cantly reduce these problems that much of the world currently faces,

and, equally importantly, some regions of the developed world may soon face

I.2.5 Water–Economy Nexus

In the past 20 years, over one trillion dollars have been spent in the United

States alone on drinking water treatment and distribution, wastewater

treatment, and residuals disposal An estimate by the U.S EPA claims that

simply to maintain current water distribution and wastewater collection

systems through 2019, $485–$896 billion (with a point estimate of $662 million)

will be needed for infrastructure and $72–$724 billion (with a point estimate

of $309 billion) will be needed for operation and maintenance [ 4 ] The

Congressional Budget Oﬃ ce estimated that in the late 1990s, the average cost

of water and wastewater services represented 0.5 percent of household income

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nationwide By 2019, water and wastewater service costs are projected to

account for 0.6–0.9 percent of national household income [ 5 ] The subsequent

increase in the cost of water will be reﬂ ected in increases across the economy

and especially in increased costs of food and energy, which are already strained

The increase in the percentage of a household’s income spent on water, energy,

and food will result in less discretionary funds for retail markets The water–

economy nexus demonstrates how the availability of fresh water impacts a

country’s potential for prosperity Acting now to enhance reclamation and

reuse and to develop new waters will ensure continued economic prosperity of

developed nations and create new economic opportunities for the developing

world

I.2.6 Water–Security Nexus

Water supply and transport logistics have been a challenge for military

campaigns since the time of ancient Rome, when water was transported great

distances by pack-animals [ 12 ] Recently, water supply has also emerged as a

high-value target for terrorism Disabling and/or contamination of urban water

distribution systems can impact thousands, and in some cases millions of

customers, and the inherently open nature of wastewater collection systems

renders them vulnerable to the weaponization of a myriad of commercial

and industrial chemicals In response the U.S EPA has initiated the

WaterSentinel Program for the design, development, and deployment of a

robust, integrated water surveillance system that will incorporate real-time

system-wide water quality monitoring, critical contaminant sampling and

analysis, and public health surveillance The extent and complexity of the

WaterSentinel Program is expected to create a powerful demand for nanoscale

contaminant sensors, distributed signal acquisition and transmission, and

decision support technology [ 13 ]

I.3 Critical Problems to be Addressed in

Water Research

All over the world, people face profound threats to the availability of suﬃ cient

safe and clean water, aﬀ ecting their health and economic well-being The

problems with economically providing clean water are growing so quickly that

incremental improvements in current methods of water puriﬁ cation could leave

much of the world with inadequate supplies of clean water in mere decades

The challenges to overcome in science, technology, and society require a

long-term vision of what needs to be solved The critical problems that will have to

be addressed over the next 20 years with regard to clean water are summarized

brieﬂ y in the following sections

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I.3.1 Availability and Sourcewater Protection

At present, the United States and much of the world lack suﬃ cient knowledge

regarding the actual amount of water stored and recharged in currently utilized

freshwater aquifers Current data indicate that levels in some monitored

aquifers are dropping rapidly Regions of the High Plains Aquifer south of the

Canadian River in New Mexico and Texas experienced water level declines of

more than 60 feet between 1980 and 1999 [ 14 ] While there are some regional

eﬀ orts to look at these issues, a global eﬀ ort to inventory and quantify the

existing ﬁ xed and recharging supplies of fresh, brackish, and saline water is

critical not only for projecting water availability and sustainable withdrawal

capacities, but also for helping scientists and engineers choose solutions that

will be viable The eﬀ ects of salting on lands and lakes, as well as contamination

rates of aquifers also need to be quantiﬁ ed

I.3.2 New Water Supplies

Meaningful increases in potable water supplies can only be achieved through

reuse of existing wastewater and development of brackish and saline sources—

from the “sea to sink to the sea again.” This eﬀ ort will need to focus on

augmenting water supplies via desalination of seawater and brackish aquifers,

as well as through direct reuse of municipal and agricultural wastewaters

Brackish aquifers and wastewaters indeed present greater challenges than

seawater desalination Critical issues to utilizing inland brackish lakes and

aquifers include developing methods and materials that can separate dissolved

solids in hard water with minimal fouling, and minimizing residuals created

during desalination and reclamation of contaminated and brackish source

waters

I.3.3 Contaminant Detection and Selective

Decontamination/Removal

Eﬃ cient removal of contaminants from all types of water sources is needed to

get the “drop of poison out of an ocean of water.” Current treatment technologies

are typically not contaminant-speciﬁ c, resulting in excessive reagent use and

removal of benign constituents and excessive generation of residuals requiring

further processing and disposal Eﬀ orts to develop more marginal water sources,

due to increasing demand and depletion of existing sources, will likely become

prohibitively expensive using conventional approaches A major cost factor in

removing trace amounts of critical contaminants from source waters is that

large quantities of benign, potable constituents are also removed Additionally,

real-time, in situ detection, adsorption, and/or catalytic destruction of potential

warfare/terrorism agents are major challenges for the water industry

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I.3.4 Pathogen Deactivation and Removal

Disinfection technologies that eﬀ ectively deactivate known and emerging

pathogens without producing toxic substances are needed to “beat chlorination.”

New and aﬀ ordable materials, methods, and systems are necessary to provide

drinking water free of harmful viral, bacterial, and protozoan pathogens, while

avoiding the formation of toxic by-products or impairing the treatment of

other contaminants A key unsolved problem is the detection and removal of

new and/or evolving infective viruses, and resistant pathogens

I.3.5 Conservation and Reuse

While projections show that conservation alone will not be enough to solve

the problems, reduction in per capita water consumption remains an important

part of the solution to the problem Conservation via improved eﬃ ciencies and

reduction in waste can dramatically reduce overall costs of providing clean

water Research eﬀ orts that focus on minimizing the withdrawal of water

and on the conversion of direct draw applications to reuse systems have the

potential to substantially reduce projected water needs, particularly for speciﬁ c

watersheds and aquifers

I.3.6 Scalability, Ramp-Up, and Technology Diﬀ usion

Researchers can make the greatest discoveries and solutions to our problems,

but unless a means to move these advances from the laboratory to full

production is possible, these innovations will remain in the laboratory Further,

many novel approaches to problems, although scientiﬁ cally intriguing, may not

take into consideration the costs of mass production or implementation The

scalability component focuses on capacity for researchers to incorporate

benchmarking and manufacturing scale-up considerations as well as facilitating

the testing and movement of new materials and procedures to industry For a

technology to be a success, the total cost cycle must be favorable and it must

win in the marketplace Moreover, with respect to potable water systems, a

history of performance eﬃ cacy and costs of installation and operation must be

available for water managers to select one technology over another with

conﬁ dence

I.4 Conclusion

There are clearly many aspects to the broad problems of water quality and

many technology and policy components to the eﬀ ort to ensure the sustainability

of water for human use This book focuses on the impacts of and opportunities

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Nanotechnology applications for clean water

Dye Nanoparticle/Fiber-Coated Membranes for

Functional Nucleic Acids for Molecular