Giuseppe Sarno

Photocatalytic properties of TiO2-functionalized tiles: influence of ceramic substrate

To confer self-cleaning properties to ceramic tiles through photocatalytic phenomena, TiO2 is deposited as thin films on their surface. However, photocatalytic properties could be strongly influenced by physico-chemical characteristics of the ceramic support. For this reason, this investigation was aimed to study the influence of porosimetric characteristics of different ceramic tiles on adsorption and photocatalytic activity induced by deposited TiO2 film in the presence of UV light. Experimental data in dark conditions showed that the porosity of the support strongly influenced the adsorption phenomenon of methylene blue (MB). Porosimetric characteristic of samples were tested by Hg intrusion. Higher porosity of the ceramic substrate increased the amount of MB adsorbed. On the contrary, photocatalytic tests have evidenced that a lower porosity of the support determined a higher MB discoloration rate. These results could be explained considering the MB internal diffusion phenomena limit the overall activity inside the porosimetric structure of functionalized tiles.

Photocatalytic Applications with Tio2-zeolites Composites Anchored on Ceramic Tiles

In this work, to increase the self-cleaning properties, TiO2/zeolite composite was supported on ceramic tiles. Functionalized tiles were prepared by a sol-gel process. Photocatalytic tests were performed at ambient temperature and atmospheric pressure using a properly designed steel reactor with a pyrex window. The irradiation of photoreactor was realized by four UV lamps. For photocatalytic activity test an aqueous solution with a 5 ppm concentration of Methylene Blue (MB) was used. Characterization results evidenced that the deposition method is able to induce the formation of anatase TiO2 strongly interacting with the tile surface without modifying the aesthetic properties of the ceramic tiles. The presence of zeolite increased the MB adsorption ability enhancing the photocatalytic performances.

Functionalization of Ceramic Tiles with N-doped TiO2 and Their Photocatalytic Function Under UV or Visible Light Irradiation

Abstract In this work, tiles functionalized with N-doped TiO2 film has been studied in the discoloration of aqueous solution of methylene blue (MB) as staining agent in presence of visible or UV light to verify the photocatalytic antistain properties of the modified prepared titania. Functionalized tiles were prepared by a TiO2 sol, starting with titanium isopropoxide as titania precursor and urea as nitrogen source, via coating technique. Photocatalytic tests were performed at ambient temperature and atmospheric pressure using a properly designed steel reactor with a Pyrex window. The irradiation of photoreactor was realized by four UV lamps or light emitting diodes (LEDs) emitting in visible region, checking both discoloration, both TOC in the solution during the time. The coating method allows obtaining N-doped TiO2 in anatase phase and its deposited amount increased linearly as a function of the number of coating steps performed. The absorption properties evidenced the ability of TiO2 modified with nitrogen of exploiting the visible light emitted by blue LEDs. In the case of UV all the functionalized tiles showed remarkably photocatalytic activity reaching the total MB discoloration after about 24 h of irradiation. When samples are irradiated with visible light, raw tile and tile functionalized with undoped TiO2 showed similar reaction rate, while tile functionalized with N-doped TiO2 has presented a discoloration activity about two times faster, together with a very high TOC removal. Therefore, the obtained results clearly indicate that N-doped TiO2 film is able to exploit both UV and visible light.