Synthesis and characterization of nanocrystalline TiO2 with application as photoactive coating on stones
- 545 Downloads
Self-cleaning photocatalytic coatings for biocalcarenite stones, based on TiO2 nanoparticles obtained by sol–gel processes at different pH values and also adding gold particles, have been investigated. The selected test material is a biocalcarenite named “pietra di Lecce” (Lecce stone), outcropping in Southern Italy. Scanning electron microscopy with energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, and Raman investigations were carried out to characterize the TiO2 nanoparticles and coatings. Nanocrystalline anatase and, to a lesser extent, brookite phases are obtained. Photocatalytic activity of the TiO2 sols and of the coatings on “pietra di Lecce” was assessed under ultraviolet irradiation, monitoring methyl orange (MeO) dye degradation as a function of time. To evaluate the harmlessness of the treatment, colorimetric tests and water absorption by capillarity were performed. The results show good photodegradation rates for titania nanosols, particularly when putting in Au particles, whereas a satisfactory chromatic compatibility between the sol and the surface of the calcarenite is found only without Au addition.
Sols of nanocrystalline titania at different pH values and with Au particles were prepared and characterized.
Satisfactory photodegradation of MeO by the sols in solution and on calcarenite-coated surfaces is obtained.
The addition of Au particles improves the photodegradation activity but gives poor chromatic results on “pietra di Lecce.”
KeywordsSol–gel titania Nanocrystalline TiO2 Biocalcarenites Self-cleaning coating Photocatalysis Anatase Brookite
- Antonioli G, Fermi F, Oleari C, Reverberi R (2004) Spectrophotometric scanner for imaging of paintings and other works of art. In: Proceedings of the Second European Conference on Color in Graphics, Imaging and Vision, Aachen, Germany, pp 219–224Google Scholar
- Balenzano F, Moresi M, Tria A (1994) Significato paleogeografico della presenza di Glauconite nella “Pietra Leccese” (Calcarenite Miocenica del Salento). Mineral Petrography Acta 37:437–450Google Scholar
- Bergamonti L, Alfieri I, Lorenzi L, Montenero A, Predieri G, Barone G, Mazzoleni P, Pasquale S, Lottici PP (2013) Nanocrystalline TiO2 by sol–gel: characterization and photocatalytic activity on Modica and Comiso stones. Appl Surf Sci 282:155–173. doi:10.1016/j.apsusc.2013.05.095 CrossRefGoogle Scholar
- Bossio A, Foresi LM, Margiotta S, Mazzei R, Salvatorini G, Donia F (2006) Stratigrafia neogenico-quaternaria del settore nord-orientale della provincia di Lecce (con rilevamento geologico alla scala 1:25.000). Geol Rom 39:63–87Google Scholar
- Folk RL (1962) Spectral subdivision of limestone types. In: Ham WE (ed) Classification of carbonate rocks—a symposium. Am Assoc Petr Geol Memoir 1:62–84Google Scholar
- Kawahara T, Konishi Y, Tada H, Tohge N, Nishi J, Ito S (2002) A patterned TiO2 (anatase)/TiO2 (rutile) bilayer-type photocatalyst: effect of the anatase/rutile junction on the photocatalytic activity. Angew Chem Int Edit 41:2811–2813. doi:10.1002/1521-3773(20020802)41:15<2811::AID-ANIE2811>3.0.CO;2-# CrossRefGoogle Scholar
- Mazzei R, Margiotta S, Foresi LM, Riforgiato F, Salvatorini G (2009) Biostratigraphy and chronostratigraphy of the Miocene Pietra Leccese in the type area of Lecce (Apulia, southern Italy). Boll Soc Paleontol I 48:129–145Google Scholar
- Panniello A, Curri ML, Diso D, Licciulli L, Locaputo V, Agostiano A, Comparelli R, Mascolo G (2012) Nanocrystalline TiO2 based films onto fibers for photocatalytic degradation of organic dye in aqueous solution. Appl Catal B Environ 121–122:190–197. doi:10.1016/j.apcatb.2012.03.019 CrossRefGoogle Scholar
- UNI 11259:2008. Determination of the hydraulic binders—rhodamine B test method. UNI Ente Nazionale Italiano di Unificazione; 2008Google Scholar
- UNI EN 10921:2001. Beni culturali—Materiali lapidei naturali ed artificiali—Prodotti idrorepellenti—Applicazione su provini e determinazione in laboratorio delle loro caratteristiche. UNI Ente Nazionale Italiano di Unificazione; 2001Google Scholar
- UNI EN 15801:2010. Conservation of cultural property—test methods—determination of water absorption by capillarity. UNI Ente Nazionale Italiano di Unificazione; 2010Google Scholar
- UNI EN 15886:2010. Conservation of cultural property—test methods—colour measurement of surfaces. UNI Ente Nazionale Italiano di Unificazione; 2010Google Scholar
- Yogi C, Kojima K, Hashishin T, Wada N, Inada Y, Della Gaspera E, Bersani M, Martucci A, Liu L, Sham TK (2011) Size effect of Au nanoparticles on TiO2 crystalline phase of nanocomposite thin films and their photocatalytic properties. J Phys Chem C 115:6554–6560. doi:10.1021/jp110581J CrossRefGoogle Scholar