PHOTOABATEMENT OF WATER POLLUTANTS IN TURBID
SUSPENSIONS BY MEANS OF PHOTOACTIVE FLUORINATED
TRANSPARENT COATINGS
W. Navarrini, Federico Persico, Maurizio Sansotera
Dept. CMIC “G.Natta”, Politecnico di Milano, via Mancinelli 7, Milano, Italy
PLAST 2015, May 6, Milano
Aim of the Research
Production of a chemically stable and resistent
coating, able to promote the photooxidation of
hydrosoluble organic pollutants[a,b]
Organic Compound
hν, TiO2
H2O, O2
Mineralization Products
Flexible water treatment system developed up
to industrial scale
[a] A. Mills, S. Le Hunte, J. Photochem. Photobiol., A 108 (1997) 1.
[b] S. Gatto, M. Sansotera, F. Persico, M. Gola, C. Pirola, W. Panzeri, W. Navarrini, C.L. Bianchi, Catal. Today, in press, doi: 10.1016/j.cattod.2014.04.031.
PLAST 2015, Milano May 6th 2015
Photocatalysis as Advanced Oxidation Process
Organic compounds
[c,d,e]
CO2, H2O, N2
CB
TiIVOH
O2-•
{HO2•, HO2-, H2O2, OH-}
TiIIIOH
O2
H2O
TiIVOH
CO2CO
, H22O,
, H2NO,
2
VB
Organic compounds
TiIVOH•+
TiIVOH
H2O
OH•
Organic compounds
H2O
CO2, H2O, N2
[c] O. Carp, C.L. Huisman, A. Reller, Prog. Solid State Chem. 32 (2004) 33.
[d] M. Sansotera, F. Persico, C. Pirola, W. Navarrini, A. Di Michele, C.L. Bianchi, Appl. Catal., B 148 (2014) 29.
[e] M. Sansotera, S. Gatto, F. Persico, C. Pirola, W. Navarrini, C.L. Bianchi, Decomposition of perfluorooctanoic acid photocatalyzed by titanium dioxide: chemical modification of
the catalyst surface induced by fluoride ions, awarded as “Best Poster on Sustainability” at the 17th ESFC, Paris, 21-25 July 2013.
PLAST 2015, Milano May 6th 2015
Photocatalysis as Advanced Oxidation Process
Organic compounds
[c,d,e]
CO2, H2O, N2
CB
TiIVOH
O2-•
{HO2•, HO2-, H2O2, OH-}
TiIIIOH
O2
H2O
TiIVOH
CO2CO
, H22O,
, H2NO,
2
VB
Organic compounds
TiIVOH•+
TiIVOH
H2O
OH•
Organic compounds
TiO2 immobilized into a
polymeric matrix
Chemical stability
UV transparency
Gas permeability
Hydrophilic
H2O
CO2, H2O, N2
IONOMERIC AMORPHOUS
FLUOROPOLYMERS
[c] O. Carp, C.L. Huisman, A. Reller, Prog. Solid State Chem. 32 (2004) 33.
[d] M. Sansotera, F. Persico, C. Pirola, W. Navarrini, A. Di Michele, C.L. Bianchi, Appl. Catal., B 148 (2014) 29.
[e] M. Sansotera, S. Gatto, F. Persico, C. Pirola, W. Navarrini, C.L. Bianchi, Decomposition of perfluorooctanoic acid photocatalyzed by titanium dioxide: chemical modification of
the catalyst surface induced by fluoride ions, awarded as “Best Poster on Sustainability” at the 17th ESFC, Paris, 21-25 July 2013.
PLAST 2015, Milano May 6th 2015
Photocatalysis as Advanced Oxidation Process
Organic compounds
[c,d,e]
CO2, H2O, N2
CB
TiIVOH
O2-•
{HO2•, HO2-, H2O2, OH-}
TiIIIOH
O2
H2O
TiIVOH
CO2CO
, H22O,
, H2NO,
2
VB
Organic compounds
TiIVOH•+
TiIVOH
H2O
OH•
Organic compounds
TiO2 immobilized into a
transparent polymeric matrix
Chemical stability
UV transparency
Gas permeability
Hydrophilic
H2O
CO2, H2O, N2
IONOMERIC AMORPHOUS
FLUOROPOLYMERS
● Easy separation of the treated solution
● Appliable to turbid solutions
● Fouling prove photocatalytic assembly
[c] O. Carp, C.L. Huisman, A. Reller, Prog. Solid State Chem. 32 (2004) 33.
[d] M. Sansotera, F. Persico, C. Pirola, W. Navarrini, A. Di Michele, C.L. Bianchi, Appl. Catal., B 148 (2014) 29.
[e] M. Sansotera, S. Gatto, F. Persico, C. Pirola, W. Navarrini, C.L. Bianchi, Decomposition of perfluorooctanoic acid photocatalyzed by titanium dioxide: chemical modification of
the catalyst surface induced by fluoride ions, awarded as “Best Poster on Sustainability” at the 17th ESFC, Paris, 21-25 July 2013.
PLAST 2015, Milano May 6th 2015
Fluorinated Ionomers
Ionomers: TFE + Vinylethers containing sulphonic or carboxylic functions[f]
• High chemical stability
• High UV transparency
• Strong acid behaviour
• Hydrophilicity
[f] W.G. Grot, Fluorinated Ionomers; W. Andrew, Ed.; PDL Handbook Series; Elsevier: Amsterdam, 2008.
PLAST 2015, Milano May 6th 2015
Fluorinated Ionomers
Ionomers: TFE + Vinylethers containing sulphonic or carboxylic functions[f]
• High chemical stability
• High UV transparency
• Strong acid behaviour
• Hydrophilicity
Water collects around
the clusters of
hydrophilic sulphonic
side chains[f]
[f] W.G. Grot, Fluorinated Ionomers; W. Andrew, Ed.; PDL Handbook Series; Elsevier: Amsterdam, 2008.
PLAST 2015, Milano May 6th 2015
High water absorption in
which H+ can move freely
Fluorinated Ionomers
Ionomers: TFE + Vinylethers containing sulphonic or carboxylic functions[f]
• High chemical stability
• High UV transparency
• Strong acid behaviour
• Hydrophilicity
MW
446
‐RF
‐CF2‐CF‐O‐CF2‐CF2‐SO2F
|
CF3
306
380
280
‐CF2‐CF2‐CF2‐CO2‐CH3
‐CF2‐CF2‐CF2‐CF2‐SO2F
‐CF2‐CF2‐SO2F
Water collects around
the clusters of
hydrophilic sulphonate
side chains[f]
[f] W.G. Grot, Fluorinated Ionomers; W. Andrew, Ed.; PDL Handbook Series; Elsevier: Amsterdam, 2008.
PLAST 2015, Milano May 6th 2015
Polymer Name
Nafion®
Flemion®
Aciplex®
Flemion®
3M Polymer
Dow Polymer
Aquivion®
Company
DuPont
Asahi Glass
Asahi Chemicals
Asahi Glass
3M
Dow Chemicals
SolvaySpecialtyPolymers
High water absorption in
which H+ can move freely
Experimental apparatus
TiO2 containing
photoactive coating[g]
Quartz sheath
Low P UV Lamp
λ = 254 nm
Wav = 5 W
Polluted
aqueous solution
Constant O2 feed
(7 L/h)
Quartz surface
AD60 10%
thermally treated
AD60 10%
non-thermally treated
AQ 6% - TiO2 10%
Magnetic
stirrer
[g] F. Persico, M. Sansotera, C.L. Bianchi, C. Cavallotti, W. Navarrini, Photocatalytic Activity of TiO2-embedded Fluorinated Transparent Coating for Oxidation of Hydrosoluble
Pollutants in Turbid Suspensions, Appl. Catal., B, 170 (2015) 83-89
PLAST 2015, Milano May 6th 2015
Photoactive Coating
Low P UV Lamp
Polluted
aqueous solution
O2 Feed
Quartz surface
AD60 10%
thermally treated
Primer coating
AD60 10%
non-thermally treated
Adhesion primer
AQ 6% - TiO2 10%
Magnetic
stirrer
TFE-MDO copolymer
Hyflon® AD60
Solvay Specialty Polymers
High chemical stability[h]
High UV transparency[i]
High hydrophobicity[i]
[h] W. Navarrini, M.V. Diamanti, M. Sansotera, F. Persico, M. Wu, L. Magagnin, S. Radice, Prog. Org. Coat. 74 (2012) 794.
[i] F. Persico, M. Sansotera, M.V. Diamanti, L. Magagnin, F. Venturini, W. Navarrini, Thin Solid Films 545 (2013) 210.
PLAST 2015, Milano May 6th 2015
Photoactive Coating
Low P UV Lamp
Polluted
aqueous solution
O2 Feed
Quartz surface
AD60 10%
thermally treated
AD60 10%
non-thermally treated
AQ 6% - TiO2 10%
Photoactive layer
Magnetic
stirrer
TFE-SFVE copolymer
Aquivion® D83-06A
Solvay Specialty Polymers
High chemical stability[j]
High UV transparency
Strong acid behaviour[j]
Hydrophilicity
[j] W. Navarrini, et al., IT L020090001, 17-10-2010.
PLAST 2015, Milano May 6th 2015
Experimental apparatus
Catalyst:
TiO2 Degussa® P25
Nanometric TiO2 (Dp = 25-85 nm)
Anatase : Rutile = 3 : 1
Low P UV Lamp
Polluted
aqueous solution
O2 Feed
Magnetic
stirrer
PLAST 2015, Milano May 6th 2015
Experimental apparatus
Catalyst:
TiO2 Degussa® P25
Nanometric TiO2 (Dp = 25-85 nm)
Anatase : Rutile = 3 : 1
Tested organic pollutants:
Rhodamine B-base (RhB)
Low P UV Lamp
Non biodegradable organic dye
C28H30N2O3 - MW = 442.56 g/mol
Polluted
aqueous solution
λmax = 554 nm
O2 Feed
Magnetic
stirrer
PLAST 2015, Milano May 6th 2015
Experimental apparatus
Catalyst:
TiO2 Degussa® P25
Nanometric TiO2 (Dp = 25-85 nm)
Anatase : Rutile = 3 : 1
Tested organic pollutants:
Rhodamine B-base (RhB)
Low P UV Lamp
Non biodegradable organic dye
C28H30N2O3 - MW = 442.56 g/mol
Polluted
aqueous solution
O2 Feed
λmax = 554 nm
Crystal Violet (CRY)
Photodegradation standard
Magnetic
stirrer
C25H31N3O - MW = 389.53 g/mol
λmax = 592 nm
PLAST 2015, Milano May 6th 2015
Experimental apparatus
Catalyst:
TiO2 Degussa® P25
Nanometric TiO2 (Dp = 25-85 nm)
Anatase : Rutile = 3 : 1
Tested organic pollutants:
Rhodamine B-base (RhB)
Low P UV Lamp
Non biodegradable organic dye
C28H30N2O3 - MW = 442.56 g/mol
Polluted
aqueous solution
O2 Feed
λmax = 554 nm
Crystal Violet (CRY)
Photodegradation standard
Magnetic
stirrer
C25H31N3O - MW = 389.53 g/mol
λmax = 592 nm
Analytical technique
UV-Visible Spectrophotometry
Lambert-Beer law: Abs = ε·[pollutant]·d
PLAST 2015, Milano May 6th 2015
Experimental apparatus
Quartz surface
Low P UV Lamp
AD60 10%
thermally treated
Polluted
aqueous solution
AD60 10%
non-thermally treated
O2 Feed
AQ 6% - TiO2 10%
Photoactive layer
Magnetic
stirrer
O2, hν
Photoactive layer
operating mode
RF-SO3-H/RHabs
Organic
Pollutant (RH)
PLAST 2015, Milano May 6th 2015
TiO2*
RF-SO3H
CO2 + H2O
+ organic intermediates
Photodegradation - Rhodamine B-base
Tested organic pollutant:
Rhodamine B-base (RhB) - [RhB]0 =
O
8·10-6
mol/L
ested photocatalysts:
Photoactive Coating (PC) - Clear solution
Photoactive Coating (PC) - Turbid solution (CaSO4, 8 g/L)
TiO2 slurry (dispersed TiO2 = TiO2 content in the coating)
•
•
•
O
CH3
N
O
CH3
PLAST 2015, Milano May 6th 2015
N
CH3
CH3
Photodegradation - Rhodamine B-base
Tested organic pollutant:
O
Rhodamine B-base (RhB) - [RhB]0 =
8·10-6
mol/L
ested photocatalysts:
Photoactive Coating (PC) - Clear solution
Photoactive Coating (PC) - Turbid solution (CaSO4, 8 g/L)
TiO2 slurry (dispersed TiO2 = TiO2 content in the coating)
O
•
•
•
CH3
N
N
O
6.0
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
PC ‐ Turbid solution
5.0
PC ‐ Clear solution
4.0
CH3
TiO2 slurry
TiO2 slurry
ln C0/C
C/C0
CH3
CH3
PC ‐ Turbid solution
PC ‐ Clear solution
3.0
2.0
1.0
0.0
0
20
40
Time (min)
60
PLAST 2015, Milano May 6th 2015
80
0
20
40
Time (min)
60
80
Photodegradation - Rhodamine B-base
Tested organic pollutant:
O
Rhodamine B-base (RhB) - [RhB]0 =
8·10-6
mol/L
ested photocatalysts:
Photoactive Coating (PC) - Clear solution
Photoactive Coating (PC) - Turbid solution (CaSO4, 8 g/L)
TiO2 slurry (dispersed TiO2 = TiO2 content in the coating)
•
•
•
6.0
CH3
N
TiO2 slurry
3.0
C
= exp(-kapp·t)
C0
2.0
1.0
Test
kapp (min-1)a
∆ [RhB]60 (%)b
PC - Clear solution
0.0923
99.4
PC - Turbid solution
0.0546
95.0
TiO2 slurry
0.0250
77.9
0.0
C/C0
0
20
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
40
Time (min)
60
80
TiO2 slurry
PC ‐ Turbid solution
PC ‐ Clear solution
a Correlation
b
0
20
40
60
80
Time (min)
PLAST 2015, Milano May 6th 2015
CH3
CH3
Pseudo-first order degradation kinetics
PC ‐ Clear solution
4.0
N
O
CH3
PC ‐ Turbid solution
5.0
ln C0/C
O
coefficients R2 higher than 0.99 for all the tests presented
RhB concentration decrease calculated after 60 min treatment
Photodegradation - Crystal Violet
Tested organic pollutant:
Crystal Violet (CRY) - [CRY]0 = 5·10-5 mol/L
ested photocatalysts:
Photoactive Coating (PC) - Clear solution
Photoactive Coating (PC) - Turbid solution (CaSO4, 8 g/L)
TiO2 slurry (dispersed TiO2 = TiO2 content in the coating)
•
•
•
PLAST 2015, Milano May 6th 2015
Photodegradation - Crystal Violet
Tested organic pollutant:
Crystal Violet (CRY) - [CRY]0 = 5·10-5 mol/L
ested photocatalysts:
Photoactive Coating (PC) - Clear solution
Photoactive Coating (PC) - Turbid solution (CaSO4, 8 g/L)
TiO2 slurry (dispersed TiO2 = TiO2 content in the coating)
•
•
•
6.0
0.9
TiO2 slurry
0.8
PC ‐ Turbid solution
0.7
PC ‐ Clear solution
TiO2 slurry
PC ‐ Turbid solution
5.0
PC ‐ Clear solution
4.0
0.6
ln C 0/C
ln C0 /C
1.0
0.5
0.4
3.0
2.0
0.3
0.2
1.0
0.1
0.0
0.0
0
20
40
Time (min)
60
PLAST 2015, Milano May 6th 2015
80
0
20
40
Time (min)
60
80
Photodegradation - Crystal Violet
Tested organic pollutant:
Crystal Violet (CRY) - [CRY]0 = 5·10-5 mol/L
ested photocatalysts:
Photoactive Coating (PC) - Clear solution
Photoactive Coating (PC) - Turbid solution (CaSO4, 8 g/L)
TiO2 slurry (dispersed TiO2 = TiO2 content in the coating)
•
•
•
6.0
TiO2 slurry
PC ‐ Turbid solution
5.0
PC ‐ Clear solution
Pseudo-first order degradation kinetics
ln C 0/C
4.0
3.0
C
= exp(-kapp·t)
C0
2.0
1.0
Test
kapp (min-1)a
∆ [CRY]60 (%)b
PC - Clear solution
0.0918
97.7
PC - Turbid solution
0.0555
95.3
TiO2 slurry
0.0300
76.0
0.0
0
20
40
Time (min)
60
80
ln C0/C
1.0
0.9
TiO2 slurry
0.8
PC ‐ Turbid solution
0.7
PC ‐ Clear solution
0.6
a Correlation
0.5
b
0.4
0.3
0.2
0.1
0.0
0
20
40
Time (min)
60
80
PLAST 2015, Milano May 6th 2015
coefficients R2 higher than 0.99 for all the tests presented
CRY concentration decrease calculated after 60 min treatment
Photodegradation - RhB, CRY
1.0
Pollutant
kapp (min-1)
PC - Clear solution
RhB
0.0923
PC - Clear solution
CRY
0.0918
PC - Turbid suspention
RhB
0.0546
PC - Turbid suspention
CRY
0.0555
RhB absorption
0.8
C/C0
Test
CRY absorption
0.6
0.4
0.2
0.0
0
Apparent independence of the kapp values
from the pollutant
20
40
Time (min)
CO2, H2O, N2
Organic compounds
TiIVOH•+
CO2, H2O, N2
CB
TiIVOH
VB
PLAST 2015, Milano May 6th 2015
80
Pollutant absorption into the photoactive
coating is the Rate Determining Step
Organic compounds
hν
60
TiIVOH
O2-•
{HO2•, HO2-, H2O2, OH-}
TiIIIOH
O2
H2O
Photoactive coating characterization
Profilometry
Quartz surface
PLAST 2015, Milano May 6th 2015
Layer
Average Thickness (μm)
AQ 6% - TiO2 10%
3.70 ± 0.44
Double AD60 10%
2.11 ± 0.19
Photoactive Coating
5.81 ± 0.63
Photoactive coating characterization
Profilometry
Quartz surface
Scanning Electron Microscope - SEM
PLAST 2015, Milano May 6th 2015
Layer
Average Thickness (μm)
AQ 6% - TiO2 10%
3.70 ± 0.44
Double AD60 10%
2.11 ± 0.19
Photoactive Coating
5.81 ± 0.63
Photoactive coating characterization
Profilometry
Quartz surface
Scanning Electron Microscope - SEM
Layer
Average Thickness (μm)
AQ 6% - TiO2 10%
3.70 ± 0.44
Double AD60 10%
2.11 ± 0.19
Photoactive Coating
5.81 ± 0.63
Atomic Force Microscopy - AFM
Average Roughness, Sa = 59.3993 nm
Root Mean Square, Sq = 82.2615 nm
PLAST 2015, Milano May 6th 2015
Photoactive coating characterization
Profilometry
Quartz surface
Scanning Electron Microscope - SEM
Layer
Average Thickness (μm)
AQ 6% - TiO2 10%
3.70 ± 0.44
Double AD60 10%
2.11 ± 0.19
Photoactive Coating
5.81 ± 0.63
Atomic Force Microscopy - AFM
Average Roughness, Sa = 59.3993 nm
Root Mean Square, Sq = 82.2615 nm
Homogenous dispersion of TiO2 in the photoactive layer
Presence of TiO2 clusters - Improvable system efficiency
PLAST 2015, Milano May 6th 2015
Photoactive coating stability
Thermogravimetric analysis - TGA
1
Delta Weight (-)
0,9
Pure AD60 decomposition starts at 450 °C
0,8
0,7
0,6
0,5
Pure Aquivion decomposition starts at 300 °C,
together with cross-link phenomena that delay
the complete degradation
0,4
0,3
0,2
Pure Hyflon® AD60
Pure Aquivion® D83-06A
0,1
0
0
100
200
300
400
500
600
700
800
900
1
Temperature (°C)
0,9
Photoactive Coating TGA curves before and after the
use are overlapping
Used Photoactive Coating appears to be unhaltered
Delta Weight (-)
0,8
0,7
0,6
0,5
0,4
0,3
0,2
Pristine Photoactive Coating
Used Photoactive Coating
0,1
0
0
100
200
300
400
Temperature (°C)
PLAST 2015, Milano May 6th 2015
500
600
700
Achievements and Future Developments
Achievements
Future developments
PLAST 2015, Milano May 6th 2015
Achievements and Future Developments
Achievements
The coating allows higher photoabatement rates than TiO2 slurry
Future developments
PLAST 2015, Milano May 6th 2015
Achievements and Future Developments
Achievements
The coating allows higher photoabatement rates than TiO2 slurry
The coating can be employed to treat even turbid solutions
Future developments
PLAST 2015, Milano May 6th 2015
Achievements and Future Developments
Achievements
The coating allows higher photoabatement rates than TiO2 slurry
The coating can be employed to treat even turbid solutions
The coating guarantees the abatement of different kinds of pollutants
Future developments
PLAST 2015, Milano May 6th 2015
Achievements and Future Developments
Achievements
The coating allows higher photoabatement rates than TiO2 slurry
The coating can be employed to treat even turbid solutions
The coating guarantees the abatement of different kinds of pollutants
Preliminary results show that the coating appears unhaltered after continuous use
Future developments
Federico
PersicoMay 6th 2015
PLAST 2015,
Milano
Achievements and Future Developments
Achievements
The coating allows higher photoabatement rates than TiO2 slurry
The coating can be employed to treat even turbid solutions
The coating guarantees the abatement of different kinds of pollutants
Preliminary results show that the coating appears unhaltered after continuous use
Future developments
Evaluation of the system efficiency towards different persistent pollutants (PFOA)
Federico
PersicoMay 6th 2015
PLAST 2015,
Milano
Achievements and Future Developments
Achievements
The coating allows higher photoabatement rates than TiO2 slurry
The coating can be employed to treat even turbid solutions
The coating guarantees the abatement of different kinds of pollutants
Preliminary results show that the coating appears unhaltered after continuous use
Future developments
Evaluation of the system efficiency towards different persistent pollutants (PFOA)
Evaluation of the system efficiency with different photocatalyst deposition (Sol-Gel)
Federico
PersicoMay 6th 2015
PLAST 2015,
Milano
Achievements and Future Developments
Achievements
The coating allows higher photoabatement rates than TiO2 slurry
The coating can be employed to treat even turbid solutions
The coating guarantees the abatement of different kinds of pollutants
Preliminary results show that the coating appears unhaltered after continuous use
Future developments
Evaluation of the system efficiency towards different persistent pollutants (PFOA)
Evaluation of the system efficiency with different photocatalyst deposition (Sol-Gel)
Evaluation of the system efficiency working with different pH conditions
PLAST 2015, Milano May 6th 2015
Achievements and Future Developments
Achievements
The coating allows higher photoabatement rates than TiO2 slurry
The coating can be employed to treat even turbid solutions
The coating guarantees the abatement of different kinds of pollutants
Preliminary results show that the coating appears unhaltered after continuous use
Future developments
Evaluation of the system efficiency towards different persistent pollutants (PFOA)
Evaluation of the system efficiency with different photocatalyst deposition (Sol-Gel)
Evaluation of the system efficiency working with different pH conditions
Optimization of the ratio TiO2 / ionomer into the coating
PLAST 2015, Milano May 6th 2015
Achievements and Future Developments
Achievements
The coating allows higher photoabatement rates than TiO2 slurry
The coating can be employed to treat even turbid solutions
The coating guarantees the abatement of different kinds of pollutants
Preliminary results show that the coating appears unhaltered after continuous use
Future developments
Evaluation of the system efficiency towards different persistent pollutants (PFOA)
Evaluation of the system efficiency with different photocatalyst deposition (Sol-Gel)
Evaluation of the system efficiency working with different pH conditions
Kinetic modelling of the system (Diffusion phenomena)
Evaluation of this metodologie for the preparation useful organic compond
PLAST 2015, Milano May 6th 2015
Acknowledgments
Politecnico di Milano
Dr. Ing. Francesco Venturini
Dr. Ing. M. H. Wu
Prof. L. Nobili (DLC)
Prof. G. Dotelli
Prof. L. Magagnin (AFM)
Prof. A. Famulari (QMC)
Prof. P. Gallo Stampino
Dr. D. Picenoni (SEM)
Mr. M. Ursini
Solvay Solexis
Dr. V. Tortelli
Dr. M. Galimberti
Dr. A. Sanguineti
Dr. S. Radice (IR)
Dr. E. Barchiesi (NMR)
Dr. R. Pieri
Ing. M. Apostolo
Università degli Studi di Milano
Prof. C.L.Bianchi
Dr. S. Vitali
Mr. A. Beretta
PLAST 2015, Milano May
6th
39
2015
Thanks for your
kind attention
PLAST 2015, Milano May 6th 2015