Potentials and limits of oxidative photocatalysisand possible applications in the field of cultural heritage

The preservation of religious art work sees the coexistence of opposing needs: first of all the fruition of the works themselves. This is ensured by promoting accessibility to a wider audience and setting up environments improving both the visibility of artifacts and well-being of guests. The second is the obvious need to protect objects exposed to the degradation caused by environmental factors. This can be reachead by creating suitable conditions for their own preservation. The works of art are made up of antique and composite materials; their proper preservation advices vary from case to case according to the kind of materials they are made of. In many cases the ideal environmental conditions for the objects are not compatible with the most appropriate ones for the audience. Usually the compromise solution is not so simple also because the is often object to physical contact by the faithful, subjected to frequent expositions and microclimate changes related to temperature and humidity excursions and connected to the presence of total suspended particulate (TSP) mainly from intensive uncombusted residue smoking from incense and votive candles. Thepreservation and conservation of works of sacred art, normally exposed to the veneration of the faithful must take place in situ. Because of their roles these peculiar type works of art cannot be placed out of context. The present discussion therefore refers to those contained by the UNI 10829/99. The experimental analysis concerned the monitoring of TSP and thermoigrometric conditions in the niche of the SS. Crucifix in the Church of St. Papino in Milazzo (ME) including a great variety of objects of different nature: bone relics, scrolls, tapestries, precious votive offerings. At present all this precious material is been pouring in clear degradation. Whatever the normative code reference, the most suitable approach now widely recognized is still the one so-called preventive conservation. A research line initiated in the nineties - still growing - is focused to the development of passive control systems with new applications on any museum cultural heritage, including ecclesiastics. Especially for this type of cultural heritage that cannot be moved or locked inside museum showcases, the passive control system offered by nanostructured titanium dioxide paints could prove effective, being oriented to dry deposition of particulate matter abatement. In the present work we emphasize its potential and highlight the criticals of such kind of technology still in fieri. © (2013) Trans Tech Publications, Switzerland.