“Inibitori organici della cristallizzazione salina nei materiali lapidei porosi. 4"

The inhibition effects of citric and phosphocitric acids on the crystallization of sodium sulphate and sodium chloride in the porous calcarenites of Noto and Palazzolo (Siracusa) were studied. These stones were quarried in the area of the Iblean Mountains, bordering the south-eastern side of Sicily. The effectiveness of these inhibitors was evaluated by measurements of the saline solution capillary flow through the porous stones specimens. Both acids proved to be ineffective toward Palazzolo stone while phosphocitric acid showed to be effective inhibitor on sodium sulphate crystal growth in Noto stone. However, it is noteworthy that in some cases the effectiveness depends on the application mode of the inhibitor. No effect was observed on sodium chloride crystal growth. The comparison of these results with those obtained in our previous works highlights the effectiveness of such inhibitor-based methodology on a variety of porous materials (e.g. brick, tuff and Noto stone). Moreover, the results are interesting in view of the practical applications for the conservation of Cultural Heritage.