PhotoActive tiles: an industrial challenge in the world of photocatalysis

Possible alternative to nano-sized TiO2 Final remarks Only nanocrystallites TiO2 is active from the photocatalytic point of view ? NO 2) Any «chance» for larger-sized TiO2 ????? YES Possible alternative to nano-sized TiO2 Micro-TiO2 in a construction material: photocatalytic tiles YES Preservation of the common tiles properties Good results as a photocatalytic materials C.L. Bianchi, et al. Advances in Materials Science and Engineering, vol. 2012, Article ID 970182, 8 pages, (2012) doi:10.1155/2012/970182 Prof. Claudia L. Bianchi

BET (m2/g) XRD Crystallite size (nm) XPS TI2p Band gap (eV) Pigmentary TiO2 Pure anatase, Uncoated surface, Commercially available (not sold as photocatalytic materials), Powder form Sample BET (m2/g) XRD Crystallite size (nm) XPS TI2p Band gap (eV) P25 50 75:25 20-25 Ti(IV) 3,21 A 12 100 110 3,15 B 11 95 3,25 C 23 40 3,28 D Mix (micro-sized + ultrafine) E 180 3,17 C.L. Bianchi, et al., “Pigmentary TiO2: a challenge for its use as photocatalyst in NOx air purification”, Chemical Eng J, 10.1016/j.cej.2014.03.078

I.R. Characterization IR spectra in the 3900 - 2800 cm-1 spectral region of samples oxidized at 300°C IR spectra in the 3900 - 2800 cm-1 spectral region of P25, after activation in different conditions

Experimental batch set-ups: NOx and VOC degradation UV lamp (320-400 nm) 1 ppm NOx T = 30°C V = 20 l Relative humidity = 40% 10 W/m2 UV lamp (320-400 nm) 400 ppm VOC T = 30°C V = 5 l Relative humidity = 40% 30 W/m2 Prof. Claudia L. Bianchi

Tests on all TiO2 in powder form: the case of sample A Gas phase Standard UV-A lamps 30 W/m2 (except for NO/NOx: 10 W/m2) Pollutant ppm Acetaldehyde 400 Micro-GC my lab Acetone Ethanol Propyl alcohol GC Milan Polytechnic – Prof. Diamanti Toluene NOx 1 chemiluminescence NO 0,4 Univ Venice - Prof. Signoretto Prof. Claudia L. Bianchi

EtOH degradation

EtOH degradation: Comparison P25/Kronos 1077 (sample A)

Tiles preparation Patent - EP2443076 Industrial porcelain-grés tiles are manufactured under high pressure by dry-pressing fine processed ceramic raw materials and finally fired at high temperatures (1200 - 1300°C) in a kiln. Photoactive porcelain-grés tiles were subsequently covered at the surface with a mixture of pure anatase micro-TiO2 and a commercial SiO2-based compound. Tiles were then treated at high temperature (approx. 680°C) for 80 min and hardly brushed to remove the powder present at the sample surface and not completely stuck. Bianchi, Capucci et al., CCC, 36 (2013) 116

1077 by Kronos (sample A) Tiles name: White Ground ActiveTM Amount of TiO2 on the tiles = 1.1 g/m2

TiO2 + SiO2-based compound TiO2 + SiO2-based compound: characterization Sample BET surface area m2/g XRPD XPS Ti 2p eV   pure TiO2 11.0 Pure anatase 458.5 TiO2 + SiO2-based compound 2.6 458.4 Prof. G. Cerrato – Turin University Prof. Claudia L. Bianchi

Mirafiori Motor Village – Torino (Italy) Final material properties: hardness lack of porosity vitrified surface durability Mirafiori Motor Village – Torino (Italy) Kindergarten «Il bruco» - L’Aquila (Italy)

Photocatalytic properties Photocatalytic properties Self-cleaning performance De-pollutant Methylen blue degradation in water (ISO 10678) Oleic acid degradation (ISO 27448-1) Photocatalytic properties Photocatalytic properties NOx degradation in both batch and plug-flow reactors Decoloration of dyes put in contact with the tiles Antibacterial activity (ISO 27447) performed by Artest Modena-Italy

PHOTOCATALYSIS: MAKES IT DIFFICULT FOR DIRT TO DEPOSIT Contact angle measurements PHOTOCATALYSIS: MAKES IT DIFFICULT FOR DIRT TO DEPOSIT Modification of Surface Hydrophilic Properties Common porcelain Photocatalytic porcelain gres tile gres tile Prof. S. Biella – Milan Polytechnique

----------------------------------- Tiles performance: NOx degradation NOx: 1000 ppb Amount of TiO2 on the tiles during the photocatalytic test: 0,004 g Amount of TiO2 in powder form during the photocatalytic test: 0,04g ----------------------------------- Time to reach 80% NOx degradation with the tiles during the photocatalytic test: 360 min Time to reach 80% NOx degradation with TiO2 in powder form during the photocatalytic test: 36 min Prof. Claudia L. Bianchi

WHO guidelines for NO2 Prof. Claudia L. Bianchi

NO2 Hourly limit value NO2 Annual limit value Case History: Hong Kong Values on the graph in μg/m3 NO2 Hourly limit value NO2 Annual limit value 01/11/2011 – 31/12/2011 Prof. Claudia L. Bianchi

Case history: Milano (Italy) Prof. Claudia L. Bianchi

Time to reach the annual mean value Tiles performance with real pollution levels Value fixed in ISO 22197-1 Time to reach the annual mean value of 40 μg/m3 h 10 W/m2 20 W/m2 NO2 inlet value Prof. Claudia L. Bianchi

Final remarks Interesting photocatalytc performance of all microsized samples in gas phase. Nano-TiO2 shows always the best results towards the photodegradation of both NOx, but with levels of real pollutions, powdered nano and micro-sized TiO2 seems to show similar photodegradation results. Photocatalytic tiles are now an industrial reality. Photocatalytic tiles, commercially available, combine porcelain-grés material features and photocatalytic properties. features Prof. Claudia L. Bianchi