Micro-sized TiO2 as photoactive catalyst coated on industrial porcelain grès tiles

in water drug photodegradation

aspirin and paracetamol

14-16 September 2016 Athens, Greece

Prof. Claudia BianchiUniversità degli Studi di Milano

European Union LegislationDIRECTIVE 2013/39/EU OF THE EUROPEAN PARLIAMENT

AND OF THE COUNCIL

of 12 August 2013 amending Directives 2000/60/EC and 2008/105/EC as regards priority substances in the field of water policy

“….the Commission shall, as far as possible within two years from 13 September2013 develop a strategic approach to pollution of water by pharmaceuticalsubstances”.

COMMISSION DIRECTIVE (EU) 2015/1787

of 6 October 2015 amending Annexes II and III to Council Directive 98/83/EC on the quality of water intended for human consumption

Programs to plan:“monitoring, parameters and frequencies, risk assessment, sampling method and sampling points regulation

14-16 September 2016 Athens, Greece

WastewaterremediationPhotoactive

porcelain grès tile

Emerging

pollutants

PhotocatalyticOxydation

Photocatalytic Oxydation: AOP

Photoactiveporcelain grès tiles:

Emerging pollutants: Aspirin &paracetamol

TiO2 catalyst

Photodegradationtest

TiO2

semiconductor

World Legislation

World Legislation

14-16 September 2016 Athens, Greece

Pharmaceutical compounds

Aspirin Paracetamol

acetoxy group (-O-C(=O)- CH3)

carboxylic acid group (-C(=O)-OH)

amide group (-NH -C(=O)-CH3)

hydroxylic group (-OH)

14-16 September 2016 Athens, Greece

Background

Traditional Physical Techniques

Transfer Organic Compounds from Water to another phase

SECONDARY

POLLUTION

TiO2 Photocatalysis

Industrially produced photoactive porcelain gres

Photoactive porcelain gres ceramic tiles

1) Preparation

Mixing and grinding Milling of raw materials in water:

clay minerals, natural minerals (feldspar, silica)

Forming by automated presses P=7000 tons

Firing in a tunnel kiln at 1300°C for 60 min

2) Photoactive modifies tiles

Covering with a suitable micro-TiO2 based-ink via digital printing (new) or spray deposition (old)

Treatment at high temperature: 680°C for 80 min

Brushing to remove unfixed powder

Photodegradation tests

Min

era

lizat

ion

%

C

on

vers

ion

% CONVERSION %: degradation of starting molecules into their by-products

Aspirin and Paracetamol disappear over time

MINERALIZATION % : degradation of all organic compounds into harmless inorganic compounds, as CO2 and H2O.

Aspirin, Paracetamol and their by-products are completely degraded over time

14-16 September 2016 Athens, Greece

Photodegradation results: comparison between spray and digital printing coatings

0

20

40

60

80

100

0 1 2 3 4 5 6 7 8 9 10

Co

nve

rsio

n (

%)

time (h)

24/

24

0

20

40

60

80

0 1 2 3 4 5 6 7 8 9 10

Min

eral

izat

ion

(%

)

time(h)

/

24

Min

era

lizat

ion

%

C

on

vers

ion

%

0

20

40

60

80

100

0 1 2 3 4 5 6 7 8 9 10

Co

nve

rsio

n (

%)

time (h)24

/

0

20

40

60

80

0 1 2 3 4 5 6 7 8 9 10

Min

eral

izat

ion

(%

)

time (h)

24

/

0

20

40

60

80

100

0 1 2 3 4 5 6 7 8 9 10

Co

nve

rsio

n (

%)

time (h)24

0

20

40

60

80

0 1 2 3 4 5 6 7 8 9 10

Min

eral

izat

ion

(%

)

time (h)24

/

Aspirin Paracetamol mixed together (1:1)

/

Comparison between spray deposition (u) and ink-jet printing (p) tiles. Aspirin (red) and Paracetamol (black) as single molecule and then in mixture (1:1)

14-16 September 2016 Athens, Greece

Photodegradation Mechanisms

Paracetamol

Aspirin

Aromatic ring cleavage

and further oxidation to CO2 and H20

14-16 September 2016 Athens, Greece

Photodegradation Mechanisms

Keto-enolic tautomericequilibrum between hydroquinone/benzoquinone [1]

Solvation phenomena by water molecules: Aspirin-5H20 complex [2]

Paracetamol

Aspirin [2] M.Karthika, K.Senthilkumar, R.Kanakaraju, Computational and Theoretical Chemistry 966 (2011) 167–179.

[1] A.G.Rincón, C.Pulgarin, N.Adler, P.Peringer, J. Photochemistry. and Photobiology A: Chem. 139 (2001) 233–241.

14-16 September 2016 Athens, Greece

14-16 September 2016 Athens, Greece

[F-] <0.50 [Ca2+] 86 [Cl-] 34 [Mg2+] 19 [SO4

2-] 58 [Na+] 18 [NO3

-] 30 [K+] 2 [NO2

-] <0.2 [NH4+] <0.1

[HCO3-] 222 [Mn2+] <0.001

pH 7.7Hardness 31 °fSpecific Conductance 681 mScm-1 (a)

(a) at 20 °C

Milan Tap water composition (mg L-1) and

chemico-phisycal characteristics

Use of tap water

Fig.6. Photocatalytic tests of paracetamol () and aspirin () as single molecule a) and mixed (b).

Conversion % (full symbol), mineralization % (empty symbol) performed with digital printing tile.

Tap water.

Photodegradation results: ink-jet printing. Tap water vs deionized water

14-16 September 2016 Athens, Greece

CONCLUSIONS

• Evaluation of industrially prepared porcelain grés tiles’ photoactivity for the water

purification

• Comparison between two different coating methods, both industrially feasible

• Study of the degradation of mixture of drugs, closer to the environmental reality

• Use of tap water, closer to the environmental reality

• Lack of deactivation of the photocatalytic materials and possible immediate reuse of the tiles

• Need a thorough study on the best reactor configuration for a real use ofphotocatalytic ceramics even in the water

In this work the following key concepts were proposed:

Thank You for your kind attention