The oxidation of sulfur in marine archaeological timbers under museum storage conditions is a recently identified problem, particularly for major artefacts such as historic ships excavated from the seabed. Recent work on the Vasa has stressed the role of iron in catalysing the oxidative degradation of the wood cellulose and the polyethylene glycols used to restore mechanical integrity to the timbers. In developing new treatment protocols for the long term preservation of Henry VIII of England's flagship, the Mary Rose, we are investigating the potential of chelating agents to neutralise and remove the iron products from the ships timbers. We have explored the use of aqueous solutions of chelating agents of calcium phytate, ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA) and ammonium citrate to extract the iron compounds. All of these solutions exhibit some level of iron removal; however the key is to find the most effective concentration at pH of around 7 of the reagent solution, to minimise the treatment time and find the most cost-effective treatment for the whole of the Mary Rose hull. Fe K-edge XAFS data from samples of Mary Rose timbers, before and after treatment by the chelating agents mentioned has been collected. The data collected provide valuable insights into the effectiveness of the treatment solutions.
[1]
R. Lowson.
Aqueous oxidation of pyrite by molecular oxygen
,
1982
.
[2]
P. Cappellen,et al.
Kinetics of microbial sulfate reduction in estuarine sediments
,
2006
.
[3]
D. Nordstrom,et al.
Initiation of aqueous pyrite oxidation by dissolved oxygen and by ferric iron
,
1987
.
[4]
N. N. Greenwood,et al.
Chemistry of the elements
,
1984
.
[5]
Magnus Sandström,et al.
Sulfur accumulation in the timbers of King Henry VIII's warship Mary Rose: a pathway in the sulfur cycle of conservation concern.
,
2005,
Proceedings of the National Academy of Sciences of the United States of America.
[6]
Matija Strlič,et al.
The role of transition metals in oxidative degradation of cellulose
,
2007
.