Synergy achieved in silver-TiO2 nanocomposites for the inhibition of biofouling on limestone. (15th August 2018)

• Record Type: Journal Article
• Authors: Becerra, J.; Zaderenko, A.P.; Sayagués, M.J.; Ortiz, R.; Ortiz, P.
• Is Part Of: Building and environment. Volume 141(2018)
• Page Start: 80
• Page End: 90
• Publication Date: 2018-08-15
• Subjects: Biopatina -- Biocide -- Limestone -- Conservation and restoration -- Silver-titanium dioxide nanocomposite -- Stone biodeterioration; Buildings -- Environmental engineering -- Periodicals; Building -- Research -- Periodicals; Constructions -- Technique de l'environnement -- Périodiques; Electronic journals; 696
• DOI: 10.1016/j.buildenv.2018.05.020
• Languages: English
• ISSNs: 0360-1323

Abstract

Abstract: Biodeterioration of stone monuments is estimated to be as high as 20–30% of the total degradation suffered by Cultural Heritage constructions. With regard to this problem, bactericidal treatments are mainly based on cleaning. These processes, while effective in the short term, require frequent reapplications increasing potential damages to the monument. Silver nanoparticles offer many advantages over traditionally employed products, such as their prolonged biocide efficacy and their low toxicity to humans and environment. The aim of this study was to evaluate the applicability and effectiveness of seven nanocomposite treatments based on titanium dioxide and/or silver nanoparticles to prevent biodeterioration of limestone monuments. These nanocomposites were characterized by UV–Visible spectrophotometry, Dynamic Light Scattering and Electron Microscopy. To assess their bactericidal activity, accelerated weathering tests were performed on limestones from the quarry of Utrera, a source widely employed in such iconic monuments as the Cathedral of Seville (Spain). Furthermore, the samples of biopatina employed in our assays stemmed from the façades of historical buildings from Seville. Our results show that silver and titanium dioxide nanocomposites stabilized by citrate achieve a high biocide effect while maintaining color alterations at a low level. Graphical abstract: Image 1 Highlights: Silver/TiO2 nanocomposites were synthesized and evaluated as treatment to prevent biopatina on limestone façades. Accelerated weathering tests were designed to optimize the effectiveness assay. Samples of biopatina employed in our assays stemmed from the façades of historical buildings. Citrate-stabilized nanocomposites showed the highest biocide effects and lower aesthetical impact.