Use of Advanced Oxidation Technologies to Destroy Contaminants of Emerging Concernin Water Treatment and Reuse Applications 

Wastewater Reuse Applications and Contaminants of Emerging Concern

Limassol, Cyprus, 13-14 September 2012

Dionysios (Dion) D. DionysiouEnvironmental Engineering and Science Program, University of Cincinnati, 

Cincinnati, Ohio, USA NIREAS‐International Water Research Center, University of Cyprus, 

Nicosia, CyprusEmail: dionysios.d.dionysiou@uc.edu

But credits go to : Former graduates, current students and collaborators

Dr. Maria Antoniou (Cyanotoxins, TiO2 Photocatalysis)

Dr. Miguel Pelaez (Cyanotoxins, VLA Photocatalysis)

Dr. Chun Zhao, Ph.D., visiting scholar, Chongqing University, China

Xuexiang He, Ph.D. student, University of Cincinnati, USA

Changseok Han, Ph.D. student, University of Cincinnati, USA

Xiaodi Duan, Ph.D. student, University of Cincinnati, USA

Helen Barndok, visiting Ph.D. student, Universidad Complutense de Madrid, Spain

Dr. Armah A. de la Cruz and Dr. Jody A. Shoemaker (US EPA)

Dr. Polycarpos Falaras, Athanasios Kontos, Vlassis Likodimos, Anastasia

Hiskia, & Groups (Demokritos Research Center, Greece)

Dr. Kevin O’Shea (Florida International University)

Dr. Despo Fatta-Kassinos and group (University of Cyprus)

Dr. Tony Burn, Dr. Patrick Dunlop (University of Ulster, Northern Ireland)

Dr. Hyeok Choi and Dr. Yongjun Chen (Nanotechnology, Membranes, AOTs)

Javed Ali Khan, Noor Samad Shah, and Sanaullah Khan, visiting scholars, Ph.D.

students, the University of Peshawar, Pakistan …………………………………………

Concerns in Surface Water Treatment and

Treatment of Wastewater for Reuse Applications Microorganisms

Trace Organic Contaminants Synthetic Organic Chemicals (SOCs)

Cyanotoxins

Pharmaceuticals and Personal Care Products (PPCPs)

Endocrine Disrupting Compounds (EDCs)

Pesticides

Antibiotics

Alturki, et al. 2010. J. Membrane Science 365 (1-2): 206-215.Drewes, et al. 2003. Water Research 37 (15): 3612-3621.Heberer, et al . 2002. Water Sci. Technol. 46(3): 81–88.

Common characteristic of trace organic contaminants Many are non-biodegradable

Many are Hydrophilic

Many are of relatively small molecular weight AOPs

HABs Contamination Events: North America

Grand Lake, OH, June 15, 2010 http://www.dailystandard.com/archive/pict_single.php?rec_id=11403

http://toxics.usgs.gov/highlights/algal_toxins/Graham, 2010, Environmental Science and Technology, 44 (19):7361–7368

Binder Lake, Iowa, Total [microcystin]=40 µg/L

Pictures Courtesy: Gerry Pinto and Chris Williams (Jacksonville University Manatee Research, GreenWater Labs./ CyanoLab, Florida), Juli Dyble (NOAA), and John Lehman (Univ. Michigan).

http://www.epa.ohio.gov/portals/35/inland_lakes/PHOTO%20GALLERY%20OF%20OHIO%20HABs.pdf

Lake Erie Near South Bass Island, 8/5/2009 (Microcystis) 

The southern tip of Pelee Island, Ontario, Canada. Sep. 4, 2009. 

http://www.surfriderlakemichigan.org/news/

HABs Contamination Events: Other CountriesBlue green‐algae bloom covering 377,000 sq km of the Baltic Sea (European Space Agency's Envisat satellite image). Lack of wind and prolonged high temperatures had triggered the largest bloom since 2005.

http://www.bbc.co.uk/news/science‐environment‐10740097

http://www.cop.noaa.gov/stressors/extremeevents/hab/current/CC_habs.aspx

Lake Taihu, China 

Valle de Bravo dam (Mexico)

July 11, 2010

http://news.bbc.co.uk/2/hi/science/nature/7758700.stm

Baltic Sea, Dec.2008

MICROCYSTIN -LR

HN

COHO

N

O CH2

O

NH

NH

O

CH3

CH3

NH

O

C

OH

O

C

NH

O

O

NH

CHN NH2

O

NH

OCH3

3-amino-9- methoxy-2,6,8-trimethyl-10-phenyldeca-4,6-dienoic acid (Adda)

Arginine

D-Methylaspartic acid

Leucine

D-Alanine

N-MethyldehydroalanineD-Glutamic acid

HN

COHO

N

O CH2

O

NH

NH

O

CH3

CH3

NH

O

C

OH

O

C

NH

O

O

NH

CHN NH2

O

NH

OCH3

Aromatic ring

Methoxy group

Conjugated double bonds

Unsaturated bonds

Site A

Site B

Site D

Site C

UV/TiO2: Observed MC-LR sites of hydroxyl radical attack#

Our results revealed 21 intermediates (as m/z) with most of them being new findings.*

*Liu et al., Environ. Sci. Technol, 37 (2003) 3214

*Song et al., Environ. Sci. Technol, 40 (2006) 3941

# Antoniou et al., Environ. Sci. Technol, 42 (2008) 8877

HNR1

R2O

O

NH

OCH3

MC-LRm/z 995.5

12

34

56

7

HNR1

R2O

O

NH

OCH3

m/z 1029.5AC49H76N10O14Mass: 1028.6

OHOH

HNR1

R2O

O

NH

OCH3

m/z 1029.5B

C49H76N10O14Mass: 1028.6

OH

OH

HNR1

R2O

O

NH

O

m/z 1063.5C

OH

OH

OHOH

C49H78N10O16Mass: 1062.56

H3C

HNR1

R2O

O

NH

O

m/z 1029.5C

C49H76N10O14Mass: 1028.6

OH

OHH3C

HN

COHO

N

O CH2

O

NH

R4

R2O

O

NHR4

OHOH

OH

HO

C49H78N10O16Mass: 1062.6

A m/z 1063.5

HN

COHO

N

O CH2

O

NH

R4

R2O

O

NHR4

OH

HO

C49H78N10O16Mass: 1062.6

B m/z 1063.5

OH

OH

Site C: Diene Bonds## Antoniou et al., Environ. Sci. Technol, 42 (2008) 8877

HN

COHO

N

O CH2

O

NH

NH

O

R3

R2O

O

NHR4 MC-LRm/z = 995.5HN

COHO

N

O

O

NH

NH

O

R3

R2O

O

NHR4

HO

OH

m/z = 1029.5E

HN

COHO

N

O

O

NH

NH

O

R3

R2O

O

NHR4 m/z = 1011.5D

O

HN

COHO

N

O O

O

NH

NH

O

R3

R2O

O

NHR4

OH

m/z = 1015.5HN

COHO

NH

O

NH2

NH

O

CH3

CH3

NH

O

COH

O

CNH

O

O

NH

CHN NH2

O

NHO

m/z = 783.4B

HN

COHO

N

O

O

NH

NH

O

R3

R2O

O

NHR4

HO

OH

m/z = 1063.5

OHOH

A

Site D: Unsaturated Bonds#

Simultaneous oxidation of the chain and the cyclic structure of MC-LR

Formation of linear intermediates

# Antoniou et al., Environ. Sci. Technol, 42 (2008) 8877

Visible Light Activation of TiO2

Explore Solar Driven TiO2-based Water Treatment Technologies- Solar light: sustainable source of energy.

Band-Gap Narrowing of TiO2 for Visible Light Activation- Metal-doping (Pt, Ag) and non metal species like N, F, S, C.

Sato, Chem. Phys. Lett 123 (1986) 126; Burda et al., Nano Lett. 3 (2003) 1049; Bacsa et al., J. Phys. Chem. 109 (2005) 5994; Wu et al., Appl. Phys. A 81 (2005) 1411.

Asahi et al., Science 283 (2001) 269; Irie et al., J. Phys. Chem. B 107 (2003) 5483.

VB

CB

h+

e-

VB

Narrowed Band gap

<3.2 eV

CB

h+

e-

VB

Band gap

3.2 eV

CB

h+

e-

Mid gap

Undoped TiO2 Mixture of N 2p and O 2p Impurity sensitization level

FLUOROSURFACTANT (Zonyl FS-300, FS) IN

ISOPROPANOL

NHO

OTi

OO

OTiHN

NHOO

OTi

OO

OTiHN

OO

NO

FTi

OO

OTi

NO

N O

FTi O

O

OTi

N

OO

NO

FTi

OO

OTi

NO

N O

FTi O

O

OTi

N

OO

NO

FTi

OO

OTi

NO

N O

FTi O

O

OTi

NOO

NO

FTi

OO

OTi

NO

N O

FTi O

O

OTi

N

NHO

OTi

OO

OTiHN

NHOO

OTi

OO

OTiHN

NHO

OTi

OO

OTiHN

NHOO

OTi

OO

OTiHN

NHO

OTi

OO

OTiHN

NHOO

OTi

OO

OTiHN

Sol-gel Synthesis route Mechanistic Aspects

ACETIC ACID pH~6.0

ETHYLENEDIAMINE (EDA)

TITANIUM PRECURSOR (TTIP)

ACETIC ACID (AA)

HEAT TREATMENT (400°C/30min)

FS:isopropanol:AA:EDA:TTIP

R:275:422:46:21

VOID

The final structure consists of close-packed spherical micelles resulting in spherical pore arrangements after

calcination.

Physicochemical Properties

Pore diameter (nm)

0 10 20 30 40 50 60

Pore

vol

ume

(cm

3 g-1)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

R=1

R=3

R=5

Pore size distribution

Relative Pressure (P/Ps)

0.0 0.2 0.4 0.6 0.8 1.0

Volu

me

Ads

orbe

d (c

m3 g-1

)

0

50

100

150

200

R=3

R=1

R=5

N2 adsorption-desorption isotherms

Type IV

isotherms

Material SBET (m2g-1) Pore volume (cm3g-1) Porosity (%)* Crystal phase Crystal size (nm)** D (101)***P25 film 57 0.303 36 anatase (75%), rutile (25%) 28 3.52

R=1 91 0.1375 35 anatase 14 3.52R=3 121 0.1984 44 anatase 12 3.51R=5 136 0.2347 48 anatase 9 3.50

* Based on pore volume and 3.9 g/cm3 of anatase density

*** Based on Bragg's Law** Based on XRD using Scherrer's equation

Structural properties significantly improved with the addition of fluorosurfactantcompared to P25.

Narrow pore size distribution indicates goodhomogeneity of the pores even at a lowsurfactant ratio.

Mesoporous materials with pore sizecontrollability during synthesis.

UV-vis spectra

Wavelength (nm)350 400 450 500 550 600

Abs

orba

nce

(a.u

)

R=5

P-25 film

geff(eV)

XRD Synthesized films are of anatase phase.

No dopant-related crystalline products under theanalyzed conditions.

Nitrogen and fluorine atoms are found either in theinterstitial or substitutional sites of the TiO2 structure.

Material geff Eg

eff

P25 film 402 3.08R=1 421 2.94R=3 427 2.89R=5 438 2.82

Effective optical band gap (Egeff)

Egeff = 1239.6/g

eff

Sun et al., Langmuir., 2005, 21, 11397-11403

Band-gap (“effective”) reduction for NF-TiO2films; shift in the absorbance spectra.

Combination of nitrogen and fluorine impuritycan induce the appearance of an absorptionband in the visible region .

XPS Spectra

Subs. N: 396.4eV

Inter. N: 398.3 and 400eV

Subs. F: 688.0 eV

Binding energy (eV)394 396 398 400 402 404

Inte

nsity

(a.u

)

N 1s

399.5 eV

Binding energy (eV)682 684 686 688 690 692 694

Inte

nsity

(a.u

)

F 1s 688.5 eV

Substitutional N-doping introduces energy statesabove the valence band while interstitial N-dopinggenerate localized intergap states with character;both induce visible light activity.

Calcination at high temperatures favors theformation of interstitial N species.

Role of nitrogen and fluorine needs to be understoodcase by case. Preparation procedures leads todifferent observations in XPS data.

Li, et al. J. Solid State Chem.

2005, 178, 3293-3302

Kontos, et al. Phys. Stat. Sol (RRL). 2008, 2, 83-85

OTi Ti

Ti

N

Ti Ti

Ti

N

Interstitial Substitutional

Di Valentin et al., Chem. Phys. 2007, 339, 44-56

Oxyanion Nitride

Material F(%) N(%)R=5 1.9 1.5

Electron Paramagnetic Resonance (EPR)

Similar behavior at 10 K.

Dominance of the intense paramagnetic N species over Ti3+ ions; F dopingpromotes N incorporation in TiO2 lattice.

EPR analysis at a) 10 K andb) room temperature.

At room temperature,peak at g=2.0030, g~2.019and g~1.988 related to Nspin species; enhancedunder light illumination.

Reference TiO2 showedweak peaks EPR linesindicative of residualsurface oxygen radicalsonly and not affected uponillumination.

Photocatalytic Evaluation of NF-TiO2 Films

0

2

4

6

8

10

12

Reference P-25 R=1 R=3 R=5

MC

-LR

deg

rada

tion

rate

x 1

0-4

( M

/min

)

180 min reaction time

# of Cycles1 2 3

MC

-LR

deg

rada

tion

rate

x 1

0-4

( M

/min

)

0

2

4

6

8

10

MC-LR degradation rate of referenceTiO2 and NF-TiO2 films at pH 3.0under visible light (>420 nm)irradiation for 180 min.

Initial MC-LR concentration: 500μg/L. Visible light intensity of 7.81 x10-5 W cm-2.

Similar degradation rates were obtainedwhen reusing the catalyst after 3 cycles undervisible light.

High mechanical stability of the films.

Loss of catalyst was negligible duringwashing and reusing. Nitrogen and fluorinedopants are incorporated into the TiO2 lattice.

Degussa P25 crystallites

TiO2 crystalliteAmorphous TiO2

heating

Micelle

Larger pore

Synthesis Approach:Surfactants as templates and low loading Degussa P25 powders ( i.e., 5, 15 g/L in the sol) as fillers*

Composite Mesoporous NF-TiO2-P25 Films

* Balasubramanian, et. al., J. Mat. Sci., 38 (2003) 823. Balasubramanian, et.al, Appl. Catal. B: Environ., 47 (2004) 73.

Chen and Dionysiou, Appl. Catal. B: Environ., 62 (2006) 255. Chen and Dionysiou, J. Mol. Catal. A: Chem., 244 (2006) 73.

Chen and Dionysiou. Appl. Catal. A: General., 317 (2007) 129. Chen and Dionysiou, Appl. Catal. B: Environ., (2008).

Physicochemical Properties of NF-TiO2-P25 Films

Structural properties significantly improved with the addition of TiO2-P25 nanoparticles.

Narrow pore size distribution with a broad largepore with 15 g/L P25. Formation of P25-associatedlarger pores.

Mesoporous materials with pore sizecontrollability during synthesis.

MaterialSBET (m2g-

1)Pore volume

(cm3g-1)Porosity

(%) Crystal phaseFilm thickness per

layer (nm)

NF-TiO2 only 89.77 0.149 36.75 anatase 648.7

5 g/L P25 111.47 0.153 37.37 anatase, rutile 777.9

15 g/L P25 100.38 0.211 45.14 anatase, rutile 981.6

Pore diameter (nm)

0 10 20 30 40 50 60

Pore

vol

ume

(cm

3 g-1)

0.00

0.05

0.10

0.15

0.20

0.25

15 g/L P25

5 g/L P25

NF-TiO2 only

Relative Pressure (P/Ps)

0.2 0.4 0.6 0.8 1.0

Volu

me

Ads

orbe

d (c

m3 g-1

)

0

20

40

60

80

100

120

140

160

NF-TiO2 only

15 g/L P25

5 g/L P25

Time (hr)

0 1 2 3 4 5 6

MC

Nor

mal

ized

Con

cent

ratio

n, C

/Co

0.0

0.2

0.4

0.6

0.8

1.0

MC-LR MC-RR MC-LA MC-YR

Simulated Solar Light

MCs Removal with NF-TiO2

Initial MCs molar concentration: 0.5 M, pH 3.0.

Time (hr)

0 1 2 3 4 5 6

MC

Nor

mal

ized

Con

cent

ratio

n, C

/Co

0.0

0.2

0.4

0.6

0.8

1.0

MC-LR MC-YR

MC-RR

MC-LA

Visible

The degradation process is a function of the surface interaction between each MC and the photocatalyst (Net charge of the toxin and hydrophobicity).

MC-RR MC-YR MC-LR MC-LA

Net charge, pH 3.0 + ─ ─ ─

Molecular weight 1038 1044 995 910Increased hydrophobicity

Dark adsorption (%)

Sample MC‐LR MC‐RR MC‐LA MC‐YR

NF‐TiO2 16.3 8.8 26.5 40.9

CYN Removal

Initial CYN molar concentration: 0.5 M, pH 3.0

Chemical structure of cylindrospermopsin (CYN)

Time (hr)

0 1 2 3 4 5 6

CYN

Nor

mal

ized

Con

cent

ratio

n, C

/Co

0.0

0.2

0.4

0.6

0.8

1.0

NF-TiO2 NF-TiO2 + 5g-L P25 NF-TiO2 + 15g-L P25

Visible light ( >420 nm)

Simulated solar light

No significant adsorption of CYN in any synthesized film. Very hydrophobic and overall positively charged under acidic conditions.

Enhanced photocatalytic degradation of CYN with higher P25 loading under solar light.

Light Dose (J/cm2)

Time (hr)

0 1 2 3 4 5 6

CYN

Nor

mal

ized

Con

cent

ratio

n, C

/Co

0.0

0.2

0.4

0.6

0.8

1.0

0 10 20 30 40

NF-TiO2

NF-TiO2 + 5g-L P25 NF-TiO2 + 15 g-L P25 HN NH

O

O

N NH

NH+

H OH

-O3SO

H3C

H

H

410 5

2

698

7

17

15

1413

1211

Formation of ROS with non-metal doped TiO2 under visible light. Possible involvement of different mechanism in which OH radicals may not be the primary oxidizing species.

Nature of the oxidation mechanism is ambiguous. Hole generated in VB may not oxidize surface hydroxyls to form ●OH.

Formation of Radical Oxygen Species (ROS) in TiO2 photocatalysis

VB

CB

O2

O2●-

H-OH

H+ + ●OHh+

e-

1O2 + H2O2●OH + OH-

Oxidized products

Pollutant

Selected Organic Contaminants(4 µmol L-1 each in mixture):

ATR

CMP

CAF

Carbamazepine (CMP)• Pharmaceutical

• Persist and accumulate in organic components

Atrazine (ATR)• Herbicide• Persistent groundwater contaminant• Banned in the European Union• Endocrine disrupting effects

Caffeine (CAF)• Frequently detected in the environment

• Potential effects on fish

Stamatelatou et al., Water Science Technology Water Supply 3 (2003): 131–137. Kolpin et al. Environ. Sci. Technol. 36(2002) :1202-1211. Ackerman et al., International Journal of Occupational and Environmental Health 13 (2007): 437–445.

Some Notes ….

Development of new AOPs or improvements of existing AOPs are on going efforts with many challenges.

New advances in the field of nanotechnology and reaction engineering show promising results and encouragement for the removal of CEC but detailed mechanistic aspects need to be understood.

Effective coupling of processes can yield targeted removal efficiencies of CEC but optimization schemes are necessary for a specific source water.

Acknowledgements

Cyprus Research Promotion Foundation throughDesmi 2009-2010 which was co-funded by theEuropean Regional Development Fund and theRepublic of Cyprus through the Research PromotionFoundation (Strategic Infrastructure Project ΝΕΑΥΠΟ∆ΟΜΗ/ΣΤΡΑΤΗ/0308/09)

NSF Collaborative Research (US-Ireland) (NumberCBET-1033317)

“Clean Water” Project (Demokritos; FP7-ENV-NMP-2008-227017).