Anoxic treatment for the disinfestation of wood cultural heritage: assessment of the effects and harmfulness on different species

Wooden artefacts, wood painted panels and historic furniture represent a significant part of our cultural heritage. Their preservation over time is a challenging task, and insect infestation still represents a primary cause of loss of cultural heritage artefacts. Anoxic conditions have proved to be effective in pest control and have been extensively applied to the management of museum collections. The present work reports on the evaluation of the effects and harmfulness of nitrogen-based anoxic treatment on different wood species with or without superficial finishings. Specimens were prepared in order to be representative of various surfaces of cultural heritage objects. A complete monitoring of the treatment effects was performed by means of a multianalytical approach. FTIR spectroscopy in the MID-IR and NIR regions was conducted to assess the absence of chemical alterations, and the results were subjected to chemometric treatment by multivariate analysis. Colorimetric characterization of the surfaces was performed to monitor any undesired colour change induced by the conservation treatment. The absence of superficial mechanical damages was evaluated by means of optical and scanning electron microscopy. The results confirmed that the anoxic procedure is not harmful to the treated surfaces with respect to aesthetic, chemical and microstructural considerations, even when the most stressful conditions are applied. As wood permeability is an important parameter in order to plan an effective intervention, in this study, a simplified method to estimate the permeability of wood to oxygen in different conditions was tested.