Wool and Reduced Sulphur Gases in Museum Air

Abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Maney Publishing and International Institute for Conservation of Historic and Artistic Works are collaborating with JSTOR to digitize, preserve and extend access to Studies in Conservation.Abstract-Wool releases a number of reduced sulphur gases during storage. The release is enhanced under UV and even sunlight irradiation or when hot (50'C). Carbonyl sulphide is the principal sulphur gas found, along with traces of carbon disulphide and, in the case of short wavelength irradiations (to 254nm), hydrogen sulphide. The presence of significant amounts of water (20-80% wool weight) markedly increases the release of COS and CS2. The results of our work agree well with general observations that suggest wool degrades through thermal or photochemical degradation of cystine-containing protein. Although wool releases COS over time it also slowly absorbs COS from air. The release of sulphur gases from fabrics into indoor museum air is probably not a critical issue considering the potential magnitude of other sources such as human bioeffluents. However, within display cases, problems are likely where wool, feathers or similar materials are displayed with metals.

Carbonyl compounds indoors in a changing climate

“…However, it is possible that the carbonyl sulfide will deplete relatively quickly from wool [9]. In the case of formaldehyde the potential heritage impact is less clear given that the subsequent oxidation is likely to affect the rate of damage the gas imposes on materials.…”

“…Similar calculations might be attempted for carbonyl sulfide, but they are likely to show much the same increase (perhaps 20% increase for a few degrees rise in temperature) that was predicted for the carboxylic and acetic acids. However, it is possible that the carbonyl sulfide will deplete relatively quickly from wool [ 9 ]. In the case of formaldehyde the potential heritage impact is less clear given that the subsequent oxidation is likely to affect the rate of damage the gas imposes on materials.…”

“…Another important carbonyl compound is carbonyl sulfide [ 8 ]. Hydrogen sulfide has long been of concern in the museum environment because of its ability to tarnish metals, but it is possible that the sulfide emitted from furnishings is carbonyl sulfide, as shown in the case of wool where at ambient temperatures it is carbonyl sulfide rather than hydrogen sulfide that is emitted [ 9 ]. It is this that explains the ability of wool to tarnish metals such as copper and silver.…”

“…The release of carbonyl sulfide from wool is strongly dependent on temperature, probably because higher temperatures encourage degradation of cystine. Experiments with a range of woolen yarns suggest that changes between ambient (~20°C) and 50°C cause one to two orders of magnitude increase in the rate of loss of carbonyl sulfide [ 9 ]. Thus, increases in room temperature would have the potential to enhance indoor concentrations.…”

Physical Adsorption of H2S Related to the Conservation of Works of Art: The Role of the Pore Structure at Low Relative Pressure

“…Wool is one of these materials, as H 2 S may be released from sulphur amino acids, particularly cystine, that makes wool proteins (Brimblecombe et al, 1992). Some materials may be a significant source inside, but just in special circumstances: when these materials are in closed environments, that is, in showcases or in rooms with poor gaseous exchange to outside.…”