Convergence of Nanotechnology and Microbiology:

Emerging Opportunities for Disinfection and Integrated Urban Water Management

Pedro J.J. Alvarez2 November 2012

Importance of Clean Water

Waterborne illnesses major cause of death Emerging pollutants in water supplies Population growth globally increases demand

Nano = Dwarf (Greek) = 10-9

“Nanotechnology is the understanding and control of matter at dimensions of roughly 1 to 100 nanometers, where unique phenomena enable novel applications.”-National Nanotechnology Initiative

4

Vision: Nano-Enabled Water Treatment & Reuse

“Nano” particles:• High surface areas• Hyper-catalytic functions• Tunable physical properties• Multifunctional membranes• Faster kinetics

Enable high-performance water treatment and remediation systems with(1) Less infrastructure, (2) Less materials/reagents

(selective targeting)(3) Lower costs & energy

clean water, enhance water

infrastructure, &enable integrated water management & reuse

Transformative Technologies to

Conceptual Improvements to Water Treatment Through Nanotechnology

5Qu X., J. Brame, Q. Li and P.J.J. Alvarez (2012). Acc. Chem. Res. doi:10.1021/ar300029v

6

Nano-Enabled Water Treatment @ Rice

• Sand filter coated with nano-magnetite to remove As (pilot in Mexico, reported by BBC, NY Times, Forbes and CBC).

• Fouling-resistant membranes that also inactivate virus (nAg, nano-TiO2)

• Pd/Au hypercatalysts to treat TCE (Pilot at Dupont site)

• Novel amino-fullerene photocatalysts to enhance UV and solar disinfection and advanced oxidation processes

0 5 10 15 20 25 30

MS

-2 P

hage

Rem

oval

Rat

io (l

og(N

/N0)

)

-5

-4

-3

-2

-1

0

HC4/UVUV alone

Photocatalytic MS-2 Virus Inactivation by Aminofullerene

J.Lee, Y.Mackeyev, M.Cho, D.Li, J.-H. Kim, L.J. Wilson, and P.J.J. Alvarez (2009). Environ. Sci. Technol. (in press)

O

OO

NH3

O

NH3

HC4Time (min)

Immobilization of amino-C60 onto silica beads facilitates separation, reuse and recycling

FFA

Con

c. (C

/C0 )

0 2 4 6 8 100.0

0 .2

0 .4

0 .6

0 .8

1 .0

1 .2

Irradiation Time (hr)

1st 2nd 3rd 4th 5th

REPETITION TEST

No loss ofphoto-activity

Lee, Mackeyev, Cho, Wilson, Kim and Alvarez (2010). Environ. Sci. Technol.44: 9488–9495.

NO C60 AGGREGATION ON THE SILICA SURFACE

(HIGHER CATALYTIC AREA)

0.2 - 0.3 mmEASILY SEPARABLE

Fluidized Photocatalytic Reactor (Swaziland)

Air in

Water in

Clean Water

out

UV lamp orother light source

Photocatalyst attached to suspended

beads

Photocatalytic degradation of emerging pollutants (pharmaceuticals, endocrine disruptors) to polisheffluents from wastewater treatment plants

Lee J., S. Hong, Y. Mackeyev, C. Lee, L.J. Wilson, J-H Kim and P.J.J. Alvarez (2011). Environ. Sci. Technol. 45: 10598–10604.

0 20 40 60 80 100 1200.0

0.2

0.4

0.6

0.8

1.0

Con

c. (C

/C0 )

Irradiation Time (min)

Ranitidine

CimetidinePropranolol

Sulfioxazole

Photocatalytic Pre-treatmentof Weathered Oil to Enhance Bioavailability and Bioremediation

Sunlight

H2O, O2

OH•, 1O2

Photocatalyst

WeatheredOil

(Recalcitrant)

HydroxylatedResidue

(Bioavailable)

OHOH

OH

CO2

Photocatalysis Increased Solubilization and Biodegradation of Weathered Oil

12

0

30

60

90

No PC P25 FG

TOC (m

g/L)

Dark

WithUV

*

*

*

* statistically significant (p <0.05)after 1-day exposure

0

100

200

300

400

0 50 100 150

BOD Con

sumed

 (mg/L)

Time (h)

UV+PC

UV

Dark

37% more BOD removed

Responsible Nanotechnology

13

"With Great Power, Comes Great Responsibility”Uncle Ben to Peter Parker in Spider Man

Paul Hermann MullerThomas Midgley

14

http://ww

w.bigelow.org/bacteria/land.jpg

Microbial-nanoparticle Interactionsto Inform Risk Assessment

• Bacteria are at the foundation of all ecosystems, and carry out many ecosystem services

• Disposal/discharge can disrupt primary productivity, nutrient cycles, biodegradation, agriculture, etc.

• Antibacterial activity may be fast-screening indicator of toxicity to higher level organisms (microbial sentinels?)

Example- Silver Nanoparticles (nAg):Effect of Size, Coating, and Ag+

O2

nAg(0)

O2

Ag+ BacteriaToxic

Bioavailable? Toxic?

Cl‐, S2‐, Cysteine, CO3

2‐, HCO3‐, 

SO42‐, PO4

3‐

Complexation?Precipitation?

Toxic?

Ag+

Bacteria

Ligands

Bioavailability and Toxicity of nAgAg+ is released only if nAg(0) is oxidized:  4Ag0 + O2 +4H+ ↔  4Ag+ + 2H2O(Solubility of Ag0 ≈ 0)

OxidizedNPs

(Ag2O)

H+

H+

Ag+

No Ag+ release under Anaerobic Conditions(Faster release for air-exposed smaller NPs)

0 20 40 60 80 100 1200

500

1000

1500

2000

2500

Ag+ d

isso

lutio

n (

g/L)

Time (h)

5 nm (Aerobic) 11 nm (Aerobic) 5 nm (Anaerobic) 11 nm (Anaerobic)

Xiu Z., Q. Zhang, H.L. Puppala, V.L. Colvin, and P.J.J. Alvarez (2012). Nanoletters. 12, 4271−4275.

No Toxicity Without Ag+ Release

0 30 60 90 120 150 180 2100

20

40

60

80

100

120

E.

col

i aliv

e (%

)

PEG-AgNPs concentration (mg/L)

Anaerobic exposure

Outside anaerobic chamber

AeratedFor 48 h

Xiu Z., Q. Zhang, H.L. Puppala, V.L. Colvin, and P.J.J. Alvarez (2012). Nanoletters. 12, 4271−4275.

Ag+ concentration (g/L)

0 100 200 300 400 500

E. c

oli k

illed

(%)

020406080

100120

PVP-nAg-25nmPVP-nAg-37nmPVP-nAg-86nmPEG-nAg-2nmPEG-nAg-5nmPEG-nAg-10nmAgNO3

nAg Toxicity Can Be Explained by Dose-Response of Released [Ag+]

Xiu Z., Q. Zhang, H.L. Puppala, V.L. Colvin, and P.J.J. Alvarez (2012). Nanoletters. 12, 4271−4275.

R2 = 0.95

“What does not kill you makes you stronger”Friedrich Nietzsche

0 5 10 15 20 25 30

60

80

100

120

140

*

**

Via

ble

E. c

oli (

%)

Ag+ concentration (g/L)

(a)

Stimulatory effect after 6 h exposure to low Ag+ concentration (Hormesis?)

Xiu Z., Q. Zhang, H.L. Puppala, V.L. Colvin, and P.J.J. Alvarez (2012). Nanoletters. 12, 4271−4275.

“Nanohype” - Berube

Trough ofDisillusionment

Slope ofEnlightenment

Plateau ofProductivity

Maturity

TechnologyTrigger

Peak ofInflated

Expectations

PositiveHype

Quo Vadis, Nano?Vi

sibi

lity

NegativeHype

Cost of Purification

Percent purity

Cos

t

High purity requirements increase separation cost due to higher energy, solvent, & process time requirements (consider tradeoffs)

Most production is done for research (small quantities of highly purified material)

Few commercial applications = low demand prices stay high

Need market-driven decrease in ENM price

Less pure amino-C60 cost less (20x) without significantly sacrificing reactivity

0

0.2

0.4

0.6

0.8

1

0 40 80 120

Rel

ativ

e C

once

ntra

tion

Time (min)

FFA-probe for 1O2

Purified

Unpurified-Soot

ConclusionsThe convergence of nanotechnology & microbiology has a great potential for meaningful disruptive innovation:

• DBP-free disinfection• Advanced (photo) oxidation• Fouling- and corrosion-

resistant surfaces• Multi-functional membranes• Responsive materials

Thanks!

Great Places I Was Educated At

Tim Vogel

CEE@Iowa (Jerry Schnoor, Rich Valentine, Gene Parkin)

Environmental Nanotechnology Team @ Rice

Vicki ColvinQilin Li Mason Tomson Mike Wong Mark Wiesner

Other CEE Colleagues @ Rice

Graduate Students and Postdocs

Ph.D. Mike Vermace; Craig Hunt; Marcio Busi da Silva; Nanh Lovanh; Alethia Vazquez; Roopa Kamath; Michal Rysz; Natalie Capiro; Delina Lyon; Rosa Dominguez, Dong Li; Diego Gomez, Jacques Mathieu

M.S.E. Gary Chesley; Sang-Chong Lieu; Pete Svebakken; Phil Kovacs; Rod Christensen; Marc Roehl; Ken Rotert; Brad Helland; Leslie Cronkhite; Annette Dietz; Bill Schnabel; Ed Ruppenkamp; Leslie Foster; Bryan Till; Nahide Gulensoy; Rebecca Gottbrath; Matt Wildman; Chad Laucamp; Todd Dejournet; Sascha Richter; Nanh Lovanh; Sara Kelley; Eric Sawvel; Jennifer Ginner; Sumeet Gandhi; Richard Keller; Jennifer Wojcik; Anitha Dasappa; Leslie Sherburne; Brett Sutton; Russ Sawvel; Andrea Kalafut; Roque Sanchez; Amy Monier; Isabel Raciny; Katherine Zodrow; Robert O’Callaham; Bill Mansfield

Postdocs Graciela Ruiz; Jose Fernandez; Byung-Taek Oh; D. Kim; Joshua Shrout; Laura Adams, Sufia Kafy; Lena Brunet; Jiawei Chen; Shaily Mahendra; Zongming Xiu; Yu Yang

Any Questions?Any Questions?