The inhibition effects of citric and phosphocitric acids on promoting efflorescence as opposed to subefflorescence growth of sodium chloride in properly selected brick and tuff was studied. The effectiveness of these inhibitors was demonstrated by measurements of the saline solution capillarity flow through the porous stones. Both acids showed to be effective only on tuff. These results can probably be rationalized considering that the inhibition effectiveness of the acids is determined by the combination of various parameters : the chemical composition of the stone, the size and distribution of pores inside the stone, the mechanism of the salt crystals growth. Scanning electron microscopy analyses showed changes in sodium chloride crystal morphology and size inside the tuff pores in the presence of the inhibitors. Moreover the inhibition effects of both citric and phosphocitric acids on the crystallization of sodium chloride-sodium sulphate mixtures was investigated by following the same methodology. Again, both the acids showed to be effective only in the case of tuff.
Acidi organici quali inibitori della cristallizzazione del cloruro di sodio e di miscele cloruro di sodio-solfato di sodio nei materiali lapidei porosi. 3
MARROCCHI, Assunta;TATICCHI, Aldo;BROGGI, Alessandra;MINUTI, Lucio;
2006
Abstract
The inhibition effects of citric and phosphocitric acids on promoting efflorescence as opposed to subefflorescence growth of sodium chloride in properly selected brick and tuff was studied. The effectiveness of these inhibitors was demonstrated by measurements of the saline solution capillarity flow through the porous stones. Both acids showed to be effective only on tuff. These results can probably be rationalized considering that the inhibition effectiveness of the acids is determined by the combination of various parameters : the chemical composition of the stone, the size and distribution of pores inside the stone, the mechanism of the salt crystals growth. Scanning electron microscopy analyses showed changes in sodium chloride crystal morphology and size inside the tuff pores in the presence of the inhibitors. Moreover the inhibition effects of both citric and phosphocitric acids on the crystallization of sodium chloride-sodium sulphate mixtures was investigated by following the same methodology. Again, both the acids showed to be effective only in the case of tuff.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
