Sun and catalysis: The Environmental Photocatalysis · Sun and catalysis: The Environmental Photocatalysis ... HOOC-CH 2-CHOH-COOH CH ... Formation mechanism of active species TiO

1 1 Environmental Nanotechnologies

Sun and catalysis:

The Environmental Photocatalysis

Dr. Eric Puzenat


Outline

I – Generality

- definition

- history

II – Principle of heterogeneous photocatalysis

III – Environmental Photocatalysis

- water treatment

- air treatment

- self-cleaning materials

IV - Conclusions


The Photocatalysis

Definition : The photocatalysis is the domain of the catalysis for which light is the activation way for the catalyst

Photochemistry :

Study of chemical changes driven by light absorption by matter

The catalysis :

A catalyst is a substance that increases the rate of a chemical reaction without changing the yield and which is unchanged in the final products Example :

-Atmospheric photochemistry

Examples :

-Enzymatic catalysis

-Acido-basic catalysis


Photochemistry vs Photocatalysis

R R* h

Photochemical reactions

Products

Photosensitization reactions

P P* h

R R* Products

P : photosensitizer

P P* h

R RA Products

P : photomediator Pd


Photocatalytic reactions

Photochemistry vs Photocatalysis

P

P*

h

R

RA

Products

P is not consumed : photocatalyst Pd

RI P is used in an amount lower than stoechiometric, but light is a stoechiometric reagent


The Photocatalysis

In homogeneous phase :

For syntheses via photocatalytic C-C bond formation:

- intermolecular addition onto double or triple C-C bonds

- intermolecular addition onto C=X bonds

- intramolecular addition onto C=C bonds

- cycloaddition

- radical coupling

Examples of photocatalyts :

Chloranil Anthraquinone

Ph2CO UO22+

Uranyl *Fagnoni et al, Chem. Rev, (2007), 107, 2725-2756


The Photocatalysis

In heterogeneous phase :

Over the last 30 years, photocatalysis is synonymous of heterogeneous photocatalysis i.e. processes consisting in irradiation of a slurry of semiconductor oxide or sulfide powder or other inorganic compounds

Examples of photocatalyts : TiO2

ZnO

CdS

-Degradation of organic pollutants

-Air treatment

-Water treatment

-Self-cleaning materials

-Water splitting for generation of hydrogen as a

fuel


Photocatalysis

material

Solid physics

Kinetics and catalysis

Analytical science

electrochemistry

Chemical ingeneering

bv

bcE/eV

h+

e-

h>Eg

C

r = k[KC/(1+KC)]

C0

rC

r = k[KC/(1+KC)]

C0

r

HOOC-CH=CH-COOH

HOOC-CH 2 -CHOH-COOH

CH3 -CHOH-COOH HOOC-CHOH-CHOH-COOH

HOOC-CHOH-COOH

HOOC-CH 2 -CHO

H2 C=CH-COOH

HOOC-CHO

HOOC-CH 2 OH

HOOC-COOH

CH3 -COOH

HCOOH

CH3 -CO-COOH

CH3 -CHO

CO2

TiO 2 -UV

Reaction pathway of the photocatalytic degradation of malic acidin contact with TiO2 at 290 nm.

malic acid

2-hydroxypropanoic acid

propanedioic acid

acetic acid

formic acid oxalic acid

formylmethanoic acid

hydroxyethanoic acid

propenoic acid

2-oxopropanoic acid

3-oxopropanoic acid

butenedioic acid (trans/cis)

acetaldehyde

(1) (2)

(3)

(4)

HOOC-CH 2 -COOH

2-hydroxypropanedioic acid

2,3-dihydroxybutanedioic acid

(lactic acid)

(pyruvic acid)

(malonaldehydic acid)

(malonic acid)

(acrylic acid)

(glycolic acid)

(glyoxylic acid)

(tartaric acid)

(tartronic acid)

(fumaric/maleic acid)

a,b

a,b a,b,c

a

a,b,c

a

a

a

a

a,b,ca

b,e

identification:a: HPLCb: GC/MSc: Capillary electrophoresisd: GCe: LC/MS

c

HOOC-CH=CH-COOH

HOOC-CH 2 -CHOH-COOHHOOC-CH 2 -CHOH-COOH

CH3 -CHOH-COOHCH3 -CHOH-COOH HOOC-CHOH-CHOH-COOH

HOOC-CHOH-COOH

HOOC-CH 2 -CHOHOOC-CH 2 -CHO

H2 C=CH-COOHH2 C=CH-COOH

HOOC-CHO

HOOC-CH 2 OHHOOC-CH 2 OH

HOOC-COOH

CH3 -COOHCH3 -COOH

HCOOH

CH3 -CO-COOHCH3 -CO-COOH

CH3 -CHOCH3 -CHO

CO2CO2

TiO 2 -UVTiO 2 -UV



malic acid


propanedioic acid

acetic acid




propenoic acid

2-oxopropanoic acid

3-oxopropanoic acid


acetaldehyde

(1) (2)

(3)

(4)

HOOC-CH 2 -COOHHOOC-CH 2 -COOH



(lactic acid)

(pyruvic acid)


(malonic acid)

(acrylic acid)

(glycolic acid)

(glyoxylic acid)

(tartaric acid)

(tartronic acid)


a,b

a,b a,b,c

a

a,b,c

a

a

a

a

a,b,ca

b,e



c


1972 : Honda et al. in Nature : H2 production with electrophotocatalysis. First proofs for photocatalytic oxidation of organic compounds in gaseous phase

1996 : first applications of photocatalysis in air and water treatment

History

1960 : - Institut de Recherhce sur la Catalyse Lyon – department of physical-chemistry (S.J. Teichner)

1975-90 : Fondamental studies and interdisciplinarities (catalysis, electro-,photoelectrochemistry, radiochemistry, photochemistry, analytical chemistry) – the domain around the World Pichat,Herrmann in France, Honda, Fujishima, Tsubomura in Japan, Bard in USA, Grätzel in Switzerland, Pelizetti in Italy, Parmon and Zamaraev in USSR). First proofs for photocatalytic oxidation of organic compounds in aqueous phase

2000 maintenant : applications and development of new industrial products


- Promotion of electrons from valence band to conduction band via intrinsic absorption of a photon with energy hEg

vb

cb E/eV

h+

e-

h>Eg

Example TiO2

Ti 3d2 4s2 Ti4+ 3d0

O 2p4 O2- 2p6

Conduction band

Valence band Eg=3,2 eV

absorption of photons with wavelenght <380nm

Photon absorption leads to the formation of {e-/h+} pairs called excitons. The recombination between electrons and holes is very fast leading to a short life time for the exciton.

Photocatalysis principle


Mobility of the photogenerated charged species (Dr. H. Gerisher (1993))

Charge separation


Herrmann, Disdier, Pichat, Chem. Phys. Lett, 108, 6(1984), 618-622

phot

ocon

duc

tivity

abso

rbanc

e

Charge mobility

Photonic of the solids

TiO2 + h absorption [e-;h+]

recombination Neutral center

charge separation

Charge mobility

Cr/TiO2 + h absorption [e-;h+]

recombination Neutral center

charge separation


Semiconductor examples

material band gap (eV) (nm)

TiO2 anatase 3.2 388

TiO2 rutile 3 414

ZrO2 3.25 382

ZnO 3.2 388

CeO2 2.95 421

Sb2O4 2.95 421

SnO2 3.5 355

V2O5 2.25 552

WO3 2.8 443

SrTiO3 3.2 388

Fe2O3 2.2 564

CdS 2.4 517


e-

h+

F

-F 2

04 r

qqF

r

he

56.0

.

.. 2

2

0

22

ne

nrH

H*

e

2*

0

2

X .rm

mε.

.em

..r

r

Between the electron and the hole, there is an electrostatic attractive force given by:

r : relative dielectric constant

Using the Bohr model

eV13.6.εm

m

.r.ε2m

.emE

2

e

*

H

2

e

2*

X

*

h

*

e

* m

1

m

1

m

1



Eg(eV) rX (Å) EX (meV)

CdS 2.6 5.7 20.8 64

ZnO 3.2 3.7 13.2 155

TiO2 3.2 184 37.8 1.1



HETEROGENEOUS CATALYSIS

1) Transfer of the reactants in the fluid phase

2) Adsorption of the reactants at the surface of the catalyst

3) Reaction in the adsorbed phase

4) Desorption of the final products

5) Removal of the final products in the fluid phase

PHOTO CATALYSIS

3.1 Absorption of photons by the solid (no photochemistry)

3.2 Creation of photo-induced electrons and holes

3.3 Electron Transfer Reactions (Ionosorption, charge neutralization, radical formation, surface reactions...)


Necessity to use nanoparticles


Oxydo-reduction on the surface of irradiated TiO2

E/eV BC

BV

Electron energy E°/ENH (V)

3.2eV

+3

+2

+1

0

HO/OH- (+1.5V)

O2/HO2 (+0.1V)

+3V

-0.2V

Ox/Red A/D


TiO2 + h {e-;h+} e- + h+

A + e- A-

Ox + e- Ox-

O2 + e- O2- superoxide anion radical

H2O2 + e- HO- + HO

O3 + e- O2 + O-

D + h+ D+

Red + h+ Red+

hydroxyl radical

H2O + h+ HO + H+

OH- + h+ HO

Oxydo-reduction on the surface of TiO2


Photocatalysis principle

h: 400 nm

TiO2

OXIDATIONRed2 Ox2 + ne-

REDUCTIONOx1 + ne- Red1

e-

e-

e-

-

+

Conduction band

O2, acceptors

Eg 3,2 eV(anatase)

Valence band

surface

H2O, donnors

O2

-, HO

2, O

H,R

+

Formation of oxidativespecies on the surface

Degradation of the molecules present near

the surface

h: 400 nm

TiO2

OXIDATIONRed2 Ox2 + ne-

REDUCTIONOx1 + ne- Red1

e-

e-

e-

-

+

Conduction band

O2, acceptors

Eg 3,2 eV(anatase)

Valence band

surface

H2O, donnors

O2

-, HO

2, O

H,R

+

Formation of oxidativespecies on the surface

Degradation of the molecules present near

the surface


H2S + 2 O2 SO4

2- + 2 H+

SH- + 2 O2+ SO4

2- + H+ S2- + 2 O2 SO4

2- SO3

2- + 1/2 O2 SO42-

S2O3

2- + 2 O2 + H2O 2 SO42- + 2 H+

NO2

- + 1/2 O2 NO3-

NH4

+ + 1/2 O2 + H2O NO3- + 2 H2O + 2 H+

H3PO3 + 1/2 O2 H3PO4 CN- + 1/2 O2 OCN- [ OCN- + 2 H2O CO3

2- + NH4+]

Compounds degraded by photocatalytic oxidation

Inorganic compounds Organic compounds

alkanes, alcohols, aldehydes, ketones, aromatics,…

Organic compounds + O2 ….. CO2 + H2O

except :

- CH4

- cyanuric acid C3H3N3O3

- fluoro-carbon compounds : C-F


(A): mass of catalyst; (B): wavelength; (C): initial concentration of reactant; (D): temperature; (E): radiant flux.

m

mopt

A r

C

r = k[KC/(1+KC)]

C 0

r

EG

λ

B r

EG

80°C 20°C

D log r

Ea = Et -

aQA

Ea = Et

0

Ea = Et + aQP

1/T

r

F

r F r F

1/2

E

Influence of the different physical parameters which govern the reaction rate


Titanium dioxide (TiO2)

Loading on earth : 0.44 % (7th element on earth)

- Ilmenite (principal mineral for Ti) oxide (TiO2,FeO,Fe2O3); 30 à 70 % of TiO2.

-Rutile (TiO2): from 93 to 96 % ; other: leucoxene (alterated ilmenite > 90 % of TiO2),

anatase (TiO2), perovskite (CaTiO3).

Application fieldsPlastics

19%

Paper industry

19%

other

2%

Paints

60%

Catalysis

Photocatalysis

Cosmetics

Pharmacy

Photovoltaîcs


Preparation of TiO2 nanoparticles for photocatalysis

Usual precursors

- TiOSO4

- TiOCl2, TiCl4

- alkoxydes de Ti

- Ti

- TiO2

Usual synthesis methods

- Hydrolysis

- Neutralisation/calcination

- Solvothermal/Hydrothermal

- Sol/gel

- Melt salts

Three-dimensional materials (anatase, rutile, brookite…)


The different allotropic forms (TiO2)

TiO2(R) : type Ramsdellite

-TiO2(H) : type Hollandite

AnataseRutile

TiO2(B) : type Wadsley

Brookite TiO2(II) : type a-PbO2

a a

TiO2(R) : type Ramsdellite

-TiO2(H) : type Hollandite

AnataseRutile

TiO2(B) : type Wadsley

Brookite TiO2(II) : type a-PbO2

a a


Application fields

Photovoltaïcs, photobatteries,

Photoelectrolysis of water.

• Photoelectrochimical properties of TiO2 :

• Photocatalysis with TiO2 :

water treatment (pesticides, dyes,…)

air treatment (VOC …)

self-cleaning materials (glass, concrete,…)


Environmental photocatalysis for water treatment


Formation mechanism of active species

TiO2 + h h+ + e-

h+ + e- N (+ énergie)

H2O H+ + OH-

OH-(aq) OH-

(ads)

OH-(ads) + h

+ OH radical hydroxyl

O2(g) O2(aq) O2 solubility at 1atm : 1mM

O2(aq) O2(ads)

O2(ads) + e- O2

- radical anion superoxyde

O2- + H+ HO2

radical hydroperoxyl


Dismutation of hydroperoxyl radicals

2 HO2 O2 + H2O2

acido-basic equilibrium HO2/O2

-

O2- + H+ HO2

pKa=4,8 Basic medium : O2-

Acidic medium : HO2

1st case : if h254 nm

H2O2 2 OH

2nd case :

H2O2 + e- OH + OH-

Formation mechanism of active species


HOOC-CH=CH-COOH


CH 3 -CHOH-COOH HOOC-CHOH-CHOH-COOH

HOOC-CHOH-COOH

HOOC-CH 2 -CHO

H 2 C=CH-COOH

HOOC-CHO

HOOC-CH 2 OH

HOOC-COOH

CH 3 -COOH

HCOOH

CH 3 -CO-COOH

CH 3 -CHO

CO 2

TiO 2 -UV

Reaction pathway of the photocatalytic degradation of malic acid

in contact with TiO2 at 290 nm.

malic acid


propanedioic acid

acetic acid




propenoic acid

2-oxopropanoic acid

3-oxopropanoic acid


acetaldehyde

(1) (2)

(3) (4)

HOOC-CH 2 -COOH



(lactic acid)

(pyruvic acid)


(malonic acid)

(acrylic acid)

(glycolic acid)

(glyoxylic acid)

(tartaric acid)

(tartronic acid)


a,b

a,b a,b,c

a

a,b,c

a

a

a

a

a,b,c a

b,e

identification: a: HPLC b: GC/MS c: Capillary electrophoresis d: GC e: LC/MS

c

Malic acid degradation


O NO2

CH3

P

CH3O

CH3OS

Fenitrothion

Phosphorothioic acid O,O-dimethyl-O-(3-methyl-4-nitrophenyl) ester

(insecticide, cholinesterase inhibitor)

Photocatalytic degradation of pesticides


TIME (MIN)

Inorganic ions formation

Disappearance of fenitrothion

A = TiO2 + UV +air ; B = TiO2 obscurité ; C= UV

O NO2

CH3

P

CH3O

CH3OS


Degradation pathways


Dyes

N N

SO3Na

ORANGE G

O

O

OH

OH

SO3Na

ALISARIN

N N

HOOC

(H3C)2N

METHYL RED

NH2

N N

NH2

SO3NaSO3Na

N N

CONGO RED

S+

N

N(CH3)2

Cl-

(H3C)2N

METHYLENE BLUE


Photocatalytic decolorization

Methylene blue

0min 15min 30min 55min

S+

N

N(CH3)2

Cl-

(H3C)2N

0min 15min 30min 60min 120min 180min

CONGO

RED

NH2

N N

NH2

SO3NaSO3Na

N N


Carbon mineralization

Decolorisation does not mean that there are no more pollutants

mineralisation

decolorisation


:

TiO2

Cellulosic

fibers

SiO2

Supported photocatalytic materials

TiO2 Nanoparticles have to be supported on porous materials to avoid filtration


Photocatalytic reactors

Cooling

Supported photocatalyst

Stirring

Lamp Supported photocatalyst

Lamp


Light on Earth surface

4% of the sunlight : 1 à

4 mW/cm2

Natural solar light sufficient for a significant

photocatalytic activity


Solar photoreactors PSA (3 modules en série)

a)

b)

12

OD 48

60º

77

60 60

154

UV

Solar Collector V 1 = 108 L

pump

Tank

c)

a)

b)

12

OD 48

60º

77

60 60

154

UV


Tank

c)

UV


Tank

c)

Vtot = 250 L

Application : Water treatment (Alméria, southern Spain)


Application : Water treatment (Alméria, southern Spain)


SOLAR PHOTOCATALYSIS: « HELIO-PHOTOCATALYSIS »

Two European Programs on « Water Potabilization by Photocatalysis in Semi-Arid Countries »

Aim : Potabilization of 1m3 water per day by photocatalysis using deposited titania in a robust solar photoreactor.

AQUACAT Project Coordinator Jean-Marie HERRMANN (LACE, France) Europe (France, Spain, Portugal, Switzerland) – North Africa (Egypt, Morocco, Tunisia)

SOLWATER Project Coordinator Julian BLANCO (PSA, Spain) Europe(Spain, Portugal, France, Switzerland, Greece) – Latin America (México, Peru, Argentina)


Water potabilisation


Photocatalysis

material

Solidphysics

Kineticsandcatalysis

Analytical science

electrochemistry


bv

bcE/eV

h+

e-

h>Eg

C

r = k[KC/(1+KC)]

C0

rC

r = k[KC/(1+KC)]

C0

r

HOOC-CH=CH-COOH



HOOC-CHOH-COOH

HOOC-CH 2 -CHO

H2 C=CH-COOH

HOOC-CHO

HOOC-CH 2 OH

HOOC-COOH

CH3 -COOH

HCOOH

CH3 -CO-COOH

CH3 -CHO

CO2

TiO 2 -UV


malic acid


propanedioic acid

acetic acid




propenoic acid

2-oxopropanoic acid

3-oxopropanoic acid


acetaldehyde

(1) (2)

(3)

(4)

HOOC-CH 2 -COOH



(lactic acid)

(pyruvic acid)


(malonic acid)

(acrylic acid)

(glycolic acid)

(glyoxylic acid)

(tartaric acid)

(tartronic acid)


a,b

a,b a,b,c

a

a,b,c

a

a

a

a

a,b,ca

b,e


c

HOOC-CH=CH-COOH



HOOC-CHOH-COOH



HOOC-CHO


HOOC-COOH

CH3 -COOHCH3 -COOH

HCOOH


CH3 -CHOCH3 -CHO

CO2CO2

TiO 2 -UVTiO 2 -UV



malic acid


propanedioic acid

acetic acid




propenoic acid

2-oxopropanoic acid

3-oxopropanoic acid


acetaldehyde

(1) (2)

(3)

(4)




(lactic acid)

(pyruvic acid)


(malonic acid)

(acrylic acid)

(glycolic acid)

(glyoxylic acid)

(tartaric acid)

(tartronic acid)


a,b

a,b a,b,c

a

a,b,c

a

a

a

a

a,b,ca

b,e



c

Photocatalysis

material

Solidphysics

Kineticsandcatalysis

Analytical science

electrochemistry


bv

bcE/eV

h+

e-

h>Eg

C

r = k[KC/(1+KC)]

C0

rC

r = k[KC/(1+KC)]

C0

r

HOOC-CH=CH-COOH



HOOC-CHOH-COOH

HOOC-CH 2 -CHO

H2 C=CH-COOH

HOOC-CHO

HOOC-CH 2 OH

HOOC-COOH

CH3 -COOH

HCOOH

CH3 -CO-COOH

CH3 -CHO

CO2

TiO 2 -UV


malic acid


propanedioic acid

acetic acid




propenoic acid

2-oxopropanoic acid

3-oxopropanoic acid


acetaldehyde

(1) (2)

(3)

(4)

HOOC-CH 2 -COOH



(lactic acid)

(pyruvic acid)


(malonic acid)

(acrylic acid)

(glycolic acid)

(glyoxylic acid)

(tartaric acid)

(tartronic acid)


a,b

a,b a,b,c

a

a,b,c

a

a

a

a

a,b,ca

b,e


c

HOOC-CH=CH-COOH



HOOC-CHOH-COOH



HOOC-CHO


HOOC-COOH

CH3 -COOHCH3 -COOH

HCOOH


CH3 -CHOCH3 -CHO

CO2CO2

TiO 2 -UVTiO 2 -UV



malic acid


propanedioic acid

acetic acid




propenoic acid

2-oxopropanoic acid

3-oxopropanoic acid


acetaldehyde

(1) (2)

(3)

(4)




(lactic acid)

(pyruvic acid)


(malonic acid)

(acrylic acid)

(glycolic acid)

(glyoxylic acid)

(tartaric acid)

(tartronic acid)


a,b

a,b a,b,c

a

a,b,c

a

a

a

a

a,b,ca

b,e



c

microbiology


Environmental photocatalysis for air treatment


Treatment of VOCs

Odorous molecules

O C H O

Cancerigen molecules

aldéhyds : HCHO, CH3CHO

aromatics : BTX :benzene, toluene, xylene

nom formule origine

butadione CH3-CO-CO-CH3 beurre rance

diméthyldisulfure CH3-S-S-CH3 chou

furfural lait brûlé

acide valérique CH3-(CH2)3-COOH odeurs corporelles

2-heptanone CH3-CO-(CH2)4-CH3 fromage fort

diméthylamine (CH3)2-NH animaux morts


Indoor air treatment for industries

Elimination of odorous nitrogen containing compounds (volatil fatty acids, mercaptans, amines). challenge: very low concentrations (g m-3).

Supported photocatalyts paper + TiO2

Gas flow : 1000 à 3000 m3/h


Hospital, restaurants,….

Domestic applications

Bad smells in fridge


TiO 2 TiO 2 TiO 2

binder

Activated carbon

Outdoor air treatment

Large volume of air to be treated

Coupling between photocatalysis and adsorption


Self-cleaning materials: Glass and concrete


Photoelectrical effect : Superhydrophilicity

*Andrew Mills, Soo-Keun Lee, Journal of Photochemistry and Photobiology A: Chemistry 152 (2002) 233–247.

Photohydroxylation of TiO2 surface




A. Mills et al./ Journal of Photochemistry and Photobiology A: Chemistry 160 (2003) 213-224

0 min

Evolution of the hydrophilicity as a function of the UV irradiation time

30 min

15 min

45 min



Dirt on glass

• Composition : Urban location

• Origins :

Ori

gine

Marine

Continentale

Anthropique

Biogénique

Geochemical origin of the dirt

Marine Continental

Anthropic

Biogenic

Marine Salt (NaCl) , oceanic wind

Biogenic pollens, seeds, microbes

Continental erosion, volcano

Anthropic human activities


Sources of organic compounds in urban environment

• Automotives and trucks : alcanes, fatty acids, PAH …

• Industries : alcanes, PAH …

• Dust : alcanes, steranes, PAH, …

• Plant pollutants : alcanes, terpenes, fatty acids …

• Domestic pollutants : PAH, alcanes …

• Cigarette smoke: nicotine, alcanes, aromatics …


2.Superhydrophilicity: Formation of a rainwater thin film

which washes away the organic dirt.

Reduction

Oxidation Pollutants degradation at the glass surface

H2O + CO2

O2

H2O

OH + H+

UV (hυ)

O2-, HO2

TiO2

Self

-Cle

an

ing

Gla

ss

Valence band

Conduction band

Eg3,2eV (anatase)

e-

-

+

e-

e-

1.Photocatalytic

degradation

Self-cleaning properties of the glass

=

photocatalysis + superhydrophilicity


Examples

V. Roméas et al. / New J. Chem., 23 (1999) 365-373

A. Mills et al./ Journal of Photochemistry and Photobiology A:

Chemistry 160 (2003) 213-224

ActivTM


Previous results on Self-Cleaning Glasses

Palmitic acid chosen as a model of fatty acid responsible for stains on glasses Rate of disappearance : 0.6 µmol/h

0

0,5

1

1,5

2

0 2 4 6 8 10 12

t (h)

ac

ide

pa

lmit

iqu

e (

mg

) .

exp 1

exp 2


Disappearance rate of CH2 and CH3

• FTIR spectra at different irradiation times :

• Degradation curves : rate expressed in cm-1 min-1

• Signification of the unit ? FTIR areas/min … thickness/min

2979,4 2960 2920 2880 2840 2806,3

0,0377

0,045

0,050

0,055

0,060

0,065

0,070

0,075

0,080

0,085

0,090

0,095

0,100

0,1030

cm-1

A

t0

t + 10’ UV

t + 20’ UV

t + 30’ UV

t + 60’ UV

2979,4 2960 2920 2880 2840 2806,3

0,0377

0,045

0,050

0,055

0,060

0,065

0,070

0,075

0,080

0,085

0,090

0,095

0,100

0,1030

cm-1

A

t0

t + 10’ UV

t + 20’ UV

t + 30’ UV

t + 60’ UV

2980 2960 2920 2880 2840 2800

(cm-1)

% A

bs.

2979,4 2960 2920 2880 2840 2806,3

0,0377

0,045

0,050

0,055

0,060

0,065

0,070

0,075

0,080

0,085

0,090

0,095

0,100

0,1030

cm-1

A

t0

t + 10’ UV

t + 20’ UV

t + 30’ UV

t + 60’ UV

2979,4 2960 2920 2880 2840 2806,3

0,0377

0,045

0,050

0,055

0,060

0,065

0,070

0,075

0,080

0,085

0,090

0,095

0,100

0,1030

cm-1

A

t0

t + 10’ UV

t + 20’ UV

t + 30’ UV

t + 60’ UV

2980 2960 2920 2880 2840 2800

(cm-1)

% A

bs.

0,0

0,5

1,0

1,5

2,0

0 10 20 30 40 50 60

Temps d'irradiation UV (min)

Air

e A

S F

TIR

(cm

-1)

Irradiation time (min) F

TIR

SA

are

a


alkanes alcohols aldehydes ketones acids

C1 G P,G

C2 G P,G

C3 G G G

C4 G G

C5 G G

C6 G G

C7 G G G G

C8 G G G G

C9 G G P,G

C10 G G P,G

C11 G G P,G

C12 G G P,G

C13 G G G

C14 G G P

C15 G

Photocatalytic degradation of palmitic acid

Identification of several by-products


SGG BIOCLEAN® Ordinary float glass photocatalytic self-cleaning glass



Self-cleaning concrete/cement

from 20 to 80% of NOx degraded


Self-cleaning concrete/cement

Dives in Misericordia church inRome Police building in Bordeaux

« Cité des Arts et de la musique » in Chambéry

Air France Aéroport Headquarter Roissy Charles de Gaulle


The Twelve Principles of Green Chemistry*

* Anastas, P.T.; Warner, J.C.; Green Chemistry: Theory and Practice, Oxford University Press:

New York, 1998, p.30. By permission of Oxford University Press

1. PreventionIt is better to prevent waste than to treat or clean up waste afetr it has been created

2. Atom EconomySynthetic methods should be designed to maximize the incorporation of all materials used in the processinto final product

3. Less Hazardous Chemical SynthesesWherever practicable, synthetic methods should be designed to use and generate substances that possesslittle or no toxicity to human health and environment

4. Designing Safer ChemicalsChemical products should be designed to effect their desired function while minimizing their toxicity

5. Safer Solvents and AuxiliariesThe use of auxiliary substances (e.g., solvents, separation agents, etc.) should be made unnecessarywherever possible and innocuous when used.

6. Design for Energy EfficiencyEnergy requirements of chemical processes should be recognize for their environmental and economicimpacts and should be minimized. If possible, synthetic methods should be conducted at ambienttemperature and pressure


The Twelve Principles of Green Chemistry*

7. Use Of Renewable FeedstocksA raw material or feedstock should be renewable rather than depleting whenever technically and economicallypracticable.

8. Reduce DerivativesUnnecessary derivatization (use of blocking groups, protection/deprotection, temporary modification ofphysical/chemical processes) should be minimized or avoided if possible, because such steps require additionalreagents and can generate waste

9. CatalysisCatalytic reagents (as selective as possible) are superior to stoichiometric reagents

10. Design for degradationChemical products should be designed so that at the end o ftheir function they break down into innocuousdegradation products and do not persist in the environment

11. Real-time analysis for Pollution PreventionAnalytical methodologies need to be further developed to allow for real-time, in-process monitoring and control prior to the formation of hazardous substances

12.Inherently Safer Chemistry for Accident Prevention

Substances and the form of a substance used in a chemical process should be chosen to minimize the potentialfor chemical accidents, including releases, expolsions, and fires

* Anastas, P.T.; Warner, J.C.; Green Chemistry: Theory and Practice, Oxford University Press: New

York, 1998, p.30. By permission of Oxford University Press


Illustration of the possible impact of Photocatalytic and Photohydrophobic properties on the ‘home of the future’*.

‘Home in the futur’.

*Andrew Mills, Soo-Keun Lee, Journal of Photochemistry and Photobiology A: Chemistry 152 (2002) 233–247.

Documents

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