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Young Researchers Seminar 2011DTU, Denmark, June 8 - 10, 2011
Young Researchers Seminar 2011DTU, Denmark, 8 – 10 June, 2011
Photocatalytic RoadsFrom
lab
tests to real
scale
applications
Dr. Eng. Elia
Boonen
Belgian
Road
Research
Centre
BRRC
2
Contents
•
Photocatalysis?•
Photocatalytic
concrete
▫
Mechanism
–
why?▫
Lab
measurements
–
important parameters
•
Pilot project
Antwerp
(2004-2005)•
New applications (2010-2011)▫
Prenormative
research
▫
PhotoPAQ
–
«
Leopold
II tunnel
»▫
ECO2Profit – « Den Hoek 3 »
•
Conclusions –
perspectives
Photocatalytic
Roads: From lab tests to real scale
applications
3
Photocatalysis?
Photocatalytic
Roads: From lab tests to real scale
applications
CO2 H2 O NO3
-
…
Pollutants
4
Photocatalytic
concrete: mechanism?
Pollutants UV Radiation
Adsorption and decomposition Photocatalytic Concrete Concrete with TiO2
CTG
•
Photo: phenomenon induced by (sun) light (UV-spectrum)
•
Catalyst: a compound which
initiates
a chemical
reaction, without being
used
during
this
reaction
Mostly
in the
form
of
microparticles
of
titanium
dioxide
(TiO2
) in the crystal form anatase
Photocatalytic
Roads: From lab tests to real scale
applications
5
Photocatalytic
concrete: why?
Photocatalytic
Roads: From lab tests to real scale
applications
Important pollutants in trafic
•
CO : carbon monoxide•
SO2
: sulphur dioxide•
NOx
: nitrogen oxides (NO and NO2
)•
CO2
: carbon dioxide•
PM : particulate matter
•
VOC : volatile organic compounds•
O3
: ozone (secondary pollutant) •
Pb: lead
Toxicity, smog formation, acid rain,…
6
NOx - nitrogen oxides (NO-NO2 )
Transport sector is responsible for over 50% of NOx
coming from human activity!
Example: Exhaust of NOx
by traffic during rush hour in Paris
Energy industries14%
manufacturing industries and construction
24%transport54%
other energy use6%
other 2%
Photocatalytic
Roads: From lab tests to real scale
applications
7
•
10.000 m²
of photocatalytic
pavement blocks as pilot project on the parking lanes of a main axe in Antwerp was constructed in 2004-2005
•
2*4.5m on a total width of 60 m!
First application in Belgium: Sideways of the “Leien” in Antwerp
Photocatalytic
Roads: From lab tests to real scale
applications
8
Pre-treatment: rinsing with distilled water and drying overnight at laboratory conditions
Photocatalytic pavement block
TiO2 containing top layer
Air inlet Air outlet
UV transmitting cover
Air inlet Air outlet
T: 23°C
R.H.: 50%
Air flow: 3 l/min
NO-conc.: 1 ppmV
Light intensity: 10 W/m²
Photocatalytic
concrete: how
to measure?
ISO 22197-1 (2007)
Photocatalytic
Roads: From lab tests to real scale
applications
9
• Semi-conductor TiO2
(anatase
form) at the surface • In the presence of UV-light (300-400nm)
• Contact with pollutants necessary•
Formed NO3
-
is adsorbed at concrete surface (alkalinity) and can
subsequently be washed away by rain
HNOOHNO 2TiO, 2hv
HNOOHNO -3
TiO,2
2hv
Lab tests: removal of NOx
Photocatalytic
Roads: From lab tests to real scale
applications
10
Lab tests: measurement set-up BRRC
Photocatalytic
Roads: From lab tests to real scale
applications
Following ISO 22197-1 (2007)
11
Example of measurement according to ISO
Photocatalytic
Roads: From lab tests to real scale
applications
-0,2
0,0
0,2
0,4
0,6
0,8
1,0
1,2
0:00:00 1:12:00 2:24:00 3:36:00 4:48:00 6:00:00 7:12:00
Time
Con
cent
ratio
n (p
pm)
NONO2NOX
5 hours of UV-irradation!
12
Example of short procedure according to BRRC
Photocatalytic
Roads: From lab tests to real scale
applications
0.0
0.2
0.4
0.6
0.8
1.0
1.2
0:00:00 0:07:12 0:14:24 0:21:36 0:28:48 0:36:00 0:43:12
Tijd
Con
cent
ratie
(ppm
)
NONO2NOX
Start UV
Stop UV
Start UV
Stop UV
13
Increase of photocatalytic reaction by:
• Increase of contact time▫
Air flow (l/min)
▫
Turbulence▫
Contact area
•
Increase of light intensity (UV-light,W/m²)•
Decrease of relative
humidity (RH %)•
Optimum TiO2
-content (efficiency -
durability)
Photocatalytic
Roads: From lab tests to real scale
applications
-25%
-20%
-15%
-10%
-5%
0%
Relative humidity [%]
Red
uctio
n of
NO
x in
flow
with
1 p
pmV
NO
conc
entr
atio
n [%
]
3030 40% 50 60 70
-0,2
0
0,2
0,4
0,6
0,8
1
1,2
0:00:00 0:20:00 0:40:00 1:00:00 1:20:00 1:40:00 2:00:00
Time
conc
(ppm
) NONO2NOx
UV intensity: 1.0 mW/cm²
UV intensity: 0.5 mW/cm²
14
Important for heterogenous photocatalysis:
•
Acces to light –
light intensity, wavelength•
Acces to pollutants: air flows, contact time, relative humidity
•
Removal of deposited pollutants: by rain or washing
Photocatalytic
Roads: From lab tests to real scale
applications
15
Pilot project: Leien
in Antwerp
(2004-2005)
Photocatalytic
Roads: From lab tests to real scale
applications
16
Results: influence of washing the pavement blocks
Photocatalytic
Roads: From lab tests to real scale
applications
00,10,20,30,40,50,60,70,80,9
9/01
/200
6 (z
.w.)
6/09
/200
6
27/0
8/20
07(z
.w.)
27/0
8/20
07
4/04
/200
5
6/09
/200
6
27/0
7/20
06
27/0
8/20
07(z
.w.)
27/0
8/20
07
9/01
/200
6 (z
.w.)
27/0
7/20
06
9/01
/200
6(z.
w.)
30 35 37 42 48 53
Positioning (nr. Amerikalei)
Min
imum
NO
-con
cent
ratio
n (p
pmV
) m
easu
red
on 2
pav
emen
t blo
cks
30 9/01/2006 (z.w.) 30 6/09/2006 30 27/08/2007 (z.w.) 30 27/08/200735 4/04/2005 35 6/09/2006 37 27/07/2006 37 27/08/2007(z.w.)37 27/08/2007 42 9/01/2006 (z.w.) 48 27/07/2006 53 9/01/2006(z.w.)
17
Results Antwerp 2010
Photocatalytic
Roads: From lab tests to real scale
applications
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
9/09/2010 A 9/09/2010 B 10/10/2010 A 10/10/2010 B 10/10/2010 C
Sample Amerikalei
Min
imum
NO
-con
cent
ratio
n (p
pmV
) m
easu
red
on 2
pav
emen
t blo
cks
=> Durable activity!
18
Increasing and decreasing light intensity
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1
1,1
0:00:00 0:30:00 1:00:00 1:30:00 2:00:00 2:30:00 3:00:00 3:30:00 4:00:00 4:30:00 5:00:00 5:30:00
Time
NO
x-co
ncen
tratio
n at
out
let (
ppm
)
NOSeries2
1000Lux
2000Lux
3000Lux
4000Lux
5000Lux
Stop NO0Lux
New developmentsNew and more efficient materials, also working under visible light:
Photocatalytic
Roads: From lab tests to real scale
applications
19
New projects (2010-2013)
“Characterisation of photocatalytic (building) materials”
Prenormative
research (NBN) into
testing
methods
PhotoPAQ
Demonstration
project
within European
Life+-programme
Application in Leopold
II-tunnel
of Brussels
ECO2PROFIT
INTERREG project in cooperation with POM Antwerp (regional development)
Application of photocatalytic
concrete with TiO2
in top layerPhotocatalytic
Roads: From lab tests to real scale
applications
20
Photocatalytic concrete: new testing methods•
Prenormative research project CCN/PN/NBN 706: comparative study of test methods within European normalisation actions (CEN/TC386/WG 2)
CTG
21
Photocatalytic concrete: new applications •
LIFE+
project PhotoPAQ: application of cementitious photocatalytic materials on the walls and roof of Leopold II tunnel in Brussels
and
measurement of effect on air pollution inside
Improvement
of air quality
?!
CTG
Cfr. photopaq.ircelyon.univ-lyon1.fr
Pollutants UV Radiation
Adsorption and decompositionPhotocatalytic Concrete
Concrete with TiO2
Photocatalytic
Roads: From lab tests to real scale
applications
22
Photocatalytic concrete: new applications (2) •
INTERREG project ECO2PROFIT: application of double layered concrete with recycled concrete aggregates (CO2
)
in the bottom layer and photo- catalytic materials (TiO2
) in the top layer on industrial site “Den Hoek 3” in Wijnegem
(province of Antwerp)
CTGPhotocatalytic
Roads: From lab tests to real scale
applications
23
Demonstration project “Den Hoek 3”
•
Test program to optimize air purifying action in top layer:▫
Testing of different materials
▫
Influence curing compound
▫
Exposed aggregates surface
▫
Simulation of durability
•
Construction of trial sections
With conservation of other properties (workability, mechanical, frost-thaw,…)
24
•
Fundamental choice for photocatalytic concrete roads:
•
Exposed aggregates surface:
noise reduction,
comfort
•
Optimization
of concrete composition
(both layers)
Spraying on the surfaceTiO2
-dispersion:
+ direct action+ cost
(“ordinary”
cement)
-
Durability (adhesion to surface)?
Mixing in the mass TiO2
in cement:
+ durable action-
cost
(higher
concentration
and double layered concrete)-
indirect action
(only the TiO2
at the surface is active)
Demonstration project “Den Hoek 3” (2)
Photocatalytic
Roads: From lab tests to real scale
applications
25
•
W/C = 0.42, Cmin = 425 kg/m³, air content: 5-8%
=> Control consistency, air content, volumetric mass,…
Concrete 0/6,3 (top layer) - Wijnegem
0
10
20
30
40
50
60
70
80
90
1008,06,34,02,01,00,2500,1250,063
Sieve size [mm]
Cum
ulat
ive
mas
s re
tain
ed [%
]
ReferentieOCW volgens berekeningARC
Composition
Material Quantity (kg)
CEM III/A 42.5 N LA 425
Sea sand 0/4 735
Porphyry 4/6,3 973
Air-entraining agent 0,65
Plasticizer 1,5
Water 178,5
Optimization of concrete composition
Photocatalytic
Roads: From lab tests to real scale
applications
26
•
Simultaneous
test plates
with
concrete of
top layer and spraying of photocatalytic dispersion on the surface
•
20
days conservation
under atmospheric conditions, and subsequent storage at RH
= (60 ±
2)% and
T = (20 ±
2)°C, for
15 days
Zone 1 (with
dispersion)
Zone 2 (without
dispersion)
Construction of trial section
Photocatalytic
Roads: From lab tests to real scale
applications
27
=> Substantial and repeatable photocatalytic efficiency
Results for air purifying action of test plates:OCW 7366/5
00,050,1
0,150,2
0,250,3
0,350,4
0,450,5
0,550,6
0,650,7
0,750,8
0,850,9
0,951
1,051,1
0:00
:00
0:02
:00
0:04
:00
0:06
:00
0:08
:00
0:10
:00
0:12
:00
0:14
:00
0:16
:00
0:18
:00
0:20
:00
0:22
:00
0:24
:00
0:26
:00
0:28
:00
0:30
:00
0:32
:00
0:34
:00
0:36
:00
0:38
:00
0:40
:00
0:42
:00
0:44
:00
0:46
:00
0:48
:00
0:50
:00
0:52
:00
0:54
:00
0:56
:00
0:58
:00
1:00
:00
1:02
:00
1:04
:00
1:06
:00
1:08
:00
1:10
:00
1:12
:00
1:14
:00
Time (uu:mm:ss)
Con
cent
ratio
n N
Ox
(ppm
)
NO ppmNOX ppmNO2 ppm
Start UV
Stop UV
Start UV
Stop UV
21.4 ± 1.9NO
11.2 ± 1.0NOx
Average reduction (%)
Photocatalytic
Roads: From lab tests to real scale
applications
28
Effect of curing compound
0
5
10
15
20
25
30
35
40
45
50
A B C DPhotocatalytic sample
Red
uctio
n N
Ox
[%]
with curing
without curing
Different products in the mass
0
10
20
30
40
50
60
70
80
90
100
1 2 3Type of TiO2 product
Red
uctio
n N
O, N
Ox
[%]
reduction NO
reduction NOx
Further testing in the lab
Effect of different materials Effect of curing compound
different photocatalytic products (1,2,3) mixed in the mass (no curing compound, modified curing procedure). Curing compound = to protect against desiccation
29
Further testing in the lab (2)
Effect of surface treatment Effect of brushing/washing
Only one type of “less active” product in mass
Effect of surface treatment
0
5
10
15
20
25
exposed aggregates smooth, formwork sawnType of surface
Red
uctio
n N
O, N
Ox
[%] reduction NO
reduction NOx
Effect of brushing/washing (durability)
0
5
10
15
20
25
30
35
40
45
50
F D D'Photocatalytic sample
Red
uctio
n N
Ox
[%]
before brushing
after brushing and washing
Simulation of traffic and/or weathering
30
•
Influence of curing compound▫
Application of photocatalytic dispersion afterwards (2-3 months)
•
Optimization of concrete composition and choice of photocatalytic materials (in mass + dispersion!)
•
Effect of exposed aggregates surface finish▫
Active components at surface ↔ specific surface area
•
Durability of the photocatalytic action (in the lab)
Conclusions test program “Den Hoek 3”
Photocatalytic
Roads: From lab tests to real scale
applications
Final choice “Den Hoek 3” = COMBINATION:•
TiO2 in mass with curing compound & spraying
of photocatalytic dispersion after 3 months •
Provisional controls of photocatalytic efficiency
(in situ & in the lab: 2011-2012)
31
Perspectives of
photocatalytic
materials•
Promising results in the lab for NOx
abatement with several photocatalytic
(building) materials
•
Durability of the air purifying performance was shown, even after more than 6 years in service
•
Translation of results obtained in laboratory towards results in
situ remains difficult:=> Further need to demonstrate effectiveness in large scale projects, including other positive effects (O3 , VOC’s, PM,…)=> Application of photocatalytic materials is not effective everywhere, e.g. pollution source and wind are very important
Contact and/or more information:Anne Beeldens, [email protected] Boonen, [email protected]
Photocatalytic
Roads: From lab tests to real scale
applications