Work

Magnesium nitrate as sustainable solution for constant RH (53%) and pollutant absorption in display cases

Year: 2025

Type: article

Abstract: The Viking Ship Museum Oslo started in 1957 using saturated salt solutions (here calcium nitrate) to stabilise the relative humidity (RH) in display cases. Three decades later, excellent results with low effort and cost were reported. However, many museums have since replaced these solutions with preconditioned silica gels. Their much lower water capacity causing more frequent need for maintenance, shifting equilibrium RH, unreliability as pollutant absorbers, and possible contamination were not considered or unknown at the time. The absorption capacity of saturated magnesium nitrate solutions for corrosive pollutant traces was studied using metal-oxide-semiconductor (MOS) gas sensors. Corrosive carbonyl pollutants (formic and acetic acid, formaldehyde, and acetaldehyde), often emitted from wood, are indeed highly absorbed. Some absorption was also demonstrated for hydrogen sulfide and sulfur dioxide. Practical application tests worldwide in museums have confirmed the advantages of this sustainable and failsafe passive method.

Source: npj Heritage Science

DOI: 10.1038/s40494-025-02111-0

Authors: Katja Franziska Siebel, Heiner Grieb, Oliver Brieger, Robin Pfeifer, Christian Bur, Gerhard Eggert

Institutions: Staatliche Akademie der Bildenden Künste Stuttgart, Saarland University

Language: English

Topic: Conservation Techniques and Studies

Subfield: Conservation

Field: Arts and Humanities

Domain: Social Sciences

SDG: Responsible consumption and production

Open Access status: hybrid

Funder: Deutsche Bundesstiftung Umwelt