A Note of Caution on the Use of Calcium Nanoparticle Dispersions as Deacidifying Agents

ABSTRACT

Calcium hydroxide nanoparticles dispersed in ethanol or 2-propanol have been proposed for deacidification treatments of cellulose-based supports and are currently adopted by many paper and paintings conservators. There is however a risk inherent in this treatment: the dispersion would acquire a highly alkaline pH in the presence of moisture, absorbed by the dispersing alcohol solvents or by the cellulose-based support. Consequently, conditions of potential risk would be created for the structural integrity of the cellulosic supports, for some organic film-forming materials and some colouring matter. The simple tests conducted in this study clearly demonstrate that this risk is real, and suggest a cautious attitude in evaluating the suitability of these nano-dispersions for the treatment of some works of art.

KEYWORDS:

• Canvas
• paper
• deacidification
• lime
• nanoparticles

Acknowledgements

Dr. Maura Sala at Innovhub Stazioni Sperimentali per l’Industria S.r.l. Area SSOG, Milano, Italy, for conducting the Karl Fischer analysis.

Disclosure statement

No potential conflict of interest was reported by the author(s).