Cit:Pel.etal:2014a
| Autor | Pel, L. and Gupta, S. and Steiger, M. |
| Jahr | 2014 |
| Titel | The effect of ferrocyanide ions on sodium chloride crystallization in salt mixtures as studied by NMR |
| Bibtex | |
| DOI | 10.5165/hawk-hhg/265 |
| Link | Datei:6 SWBSS-2014 Pel etal.pdf |
| Bemerkungen | In: De Clercq, Hilde (editor): Proceedings of SWBSS 2014. Third International Conference on Salt Weathering of Buildings and Stone Sculptures Royal Institute for Cultural Heritage, Brussels, Belgium, 14-16 October 2038, S. 89-100 |
Eintrag in der Bibliographie
Keywords[Bearbeiten]
salt mixture, crystallization, drying, inhibitor, NMR
Abstract[Bearbeiten]
The use of crystallization inhibitors such as ferrocyanide has been proposed as a potential preventive treatment against salt damage of historical monuments. It has been extensively tested for crystallization of single salts, where it has shown to be effective. However, in practice there are always mixtures of salts present. Therefore, before using inhibitors in practice, there is a strong need to explore their effect on salt mixtures. A main obstacle is the measurement of the individual salt contentration in a mix, which is necessary to determine the ternary phase diagram. We have developed a NMR setup in which we are able to measure quasi-simultaneously Na, Li and H, giving the possibility to measure both the Na and Li concentration. We have also incorporated a digital microscope, giving the possibility to perform time-lapse microscopy of the crystallization. This gives the possibility to connect the measured concentrations in a mixture with the visual point of crystallization.In this research, we studied the effect of ferrocyanide ions on NaCl crystallization as single salt and in a mixture with LiCl. A series of micro droplet drying experiments was undertaken. For a NaCl solution droplet, in the presence of the inhibitor, a significantly higher supersaturation, in the order of 10 M, prior to the onset of crystallization and a change in crystal morphology were observed. For the mixtures of NaCl - LiCl, the NaCl supersaturation was much lower in the presence of the inhibitor than for the single salt. However, a significant change in the crystal morphology was seen in the presence of inhibitor for these salt mixtures.