Determining crystalline phases formed by iron and sulphur in wood samples from ancient waterlogged shipwrecks through neutron diffraction

This proposal focuses on the treatment of degraded wood from ancient waterlogged shipwrecks, damaged by the formation of acid precursors such as pyrite due to anaerobic bacterial activity. These compounds can oxidize, producing sulfuric acid, which further degrades the wood. To counteract this, we are exploring the use of Calcium Hydroxide Nanoparticles (CH-NPs) for their deacidifying and stabilizing properties, aiming to neutralize acidic conditions and prevent further damage. The main objective is to assess the distribution and quantity of iron and sulfur compounds within the wood, which is essential for optimizing the treatment. Neutron diffraction, a non-destructive technique, plays a key role in this study. It allows the identification and quantification of crystalline phases such as pyrite, greigite, and marcasite, providing information about their depth and extent. This technique enables internal structural analysis without altering the samples. We will perform measurements on three wood samples, both before and after artificial acidification, to monitor changes in sulfur-containing phases and their transformation into sulfuric acid. This will help us trace the penetration of acidic precursors and determine the optimal depth for nanoparticle treatment. Understanding the distribution of these compounds will enhance the effectiveness of the treatment, ensuring the long-term preservation of the artefacts.