The sulphur threat to marine archaeological artefacts : acid and iron removal from the Vasa

Summary, in English

An outbreak of acidity and sulphate salts was observed on the hull of the 17th-century Swedish warship Vasa, following humidity variations in the Vasa Museum during the rainy summer in 2000. Analyses of total sulphur in oak cores sampled from 16 locations showed, in the outermost 2 cm., mean concentrations betwen 0.2 and 6 mass percent. Synchrotron-based sulphur K-edge X-ray absorption spectroscopy revealed that a large amount of elemental sulphur in the moist wood was being oxidised to sulphuric acid, possibly catalysed by iron compounds, with the overall rate estimated to be about 100 kg sulphuric acid annually. Associated acid catalysed hydrolysis of the cellulose threatens the future preservation of the vessel. Results of tests of proposed new treatments using chelating agents to extract iron compounds from waterlogged wood and simultaneously neutralise acid are presented.

• Författare: Magnus Sandström; Farideh Jalilehvand; Ingmar Persson; Yvonne Fors; Emiliana Damian; Ulrik Gelius; Ingrid Hall-Roth; Lovisa Dal; Vicki Richards; Ian Godfrey
• Redaktör: Joyce H. Townsend; Katherine Eremin; Annemie Adriaens
• Publiceringsår: 2003
• Språk: Engelska
• Sidor: 79-87
• Publikation/Tidskrift/Serie: Conservation science 2002 : papers from the conference held in Edinburgh, Scotland 22-24 May 2002
• Dokumenttyp: Konferensbidrag
• Förlag: Archetype Publications
• Ämne: Other Natural Sciences; Other Humanities
• Nyckelord: Vasa; sulphur; sulphuric acid; X-ray spectroscopy; iron; chelates; waterlogged wood; shipwreck; Vasa (regalskepp); Restaurering; Konservering (museiteknik); Marinarkeologi
• Status: Published
• ISBN/ISSN/Övrigt: ISBN: 1873132883