Novel hydrogels for the selective removal of bio-contaminants from stone artworks. A case study: Rupestrian Church Madonna dei Derelitti in Matera

This research aims to report the application ‘in situ’ of a hydrogel comprised of sodium alginate as an inert matrix and sodium dichloroisocyanurate (NaDCC) which slowly releases hypochlorite as a biocide agent for the removal of bio-contaminants from calcarenite artworks [1]. Our biocide hydrogel proved to be effective in removing biotic contamination from the surface of calcareous stone of the interior area of the rupestrian Church of Madonna dei Derelitti, located in Matera. The condition of the internal walls was assessed before and after the cleaning procedure. The sampling of biotic colonizers, their molecular identification, and biological degradation were carried out together with the XPS characterization to verify the effectiveness of the detergent hydrogel [2, 3]. Simultaneously, photo images and colorimetric measurements allowed the establishment of color differences induced by treatments