Abstract
Background: Calcareous materials, like marble used in connection with cultural heritage objects such as statues and pedestals, or as wall facings on buildings, often show a brownish staining owing to contact with iron metal or ironcontaining minerals in the stone. The discolouration alters the appearance of the stone, which is undesirable from an aesthetic point of view. Despite rust staining being a conspicuous phenomenon and numerous works that have dealt with the problem of removing rust stains, a simple and non-toxic method has so far been missing. This paper describes a highly efficient method for cleaning rust stains from marble by introducing the chelating amino acid cysteine in a Laponite poultice in combination with the strong reducing agent sodium dithionite. Results: Cleaning experiments were performed on artificially discoloured samples of various types of Carrara Bianco marble and on naturally rust stained marble. To begin with, solutions of cysteine in combination with sodium dithionite and ammonium carbonate were tested by immersion of samples into the different solutions. Secondly, solutions of cysteine and sodium dithionite with and without buffering were used in a poultice consisting of Laponite® RD, Arbocel® BC1000 and CMC. The poultice was applied on three different marble types: Carrara Fabricotti, Carrara Vagli and Carrara La Piana. Thirdly, the optimized method was tested on original rust stained material of Greenlandic marble, which has been used as wall facing, and finally in situ in Copenhagen on a larger area of The Marble Church showing rust stains due to pyrite oxidation. The cleaning results were evaluated by visual observations, cross sections, and etching of the surface by testing on high gloss marble. Conclusion: Cleaning of iron-discoloured marble surfaces has been investigated and a new method for removal of rust stained marble has been developed. A solution of 0.1 M cysteine and 0.1 M sodium dithionite in a poultice consisting of Laponite® RD/Arbocel® BC1000/CMC = 10:10:1 has shown to be a fast, simple, cheap, and non-toxic, do-it-yourself method.
| Original language | English |
|---|---|
| Article number | 12 |
| Journal | Heritage Science |
| Volume | 4 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 2016 |
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Keywords
- Arbocel
- Cleaning
- Cysteine
- Dithionite
- Laponite
- Marble
- Poultice
- Rust stain
ASJC Scopus subject areas
- Conservation
- Archaeology
- Archaeology
Cite this
Effective cleaning of rust stained marble. / Spile, Sanne; Suzuki, Takayoshi; Bendix, Jesper; Simonsen, Kim Pilkjær.
In: Heritage Science, Vol. 4, No. 1, 12, 2016.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Effective cleaning of rust stained marble
AU - Spile, Sanne
AU - Suzuki, Takayoshi
AU - Bendix, Jesper
AU - Simonsen, Kim Pilkjær
PY - 2016
Y1 - 2016
N2 - Background: Calcareous materials, like marble used in connection with cultural heritage objects such as statues and pedestals, or as wall facings on buildings, often show a brownish staining owing to contact with iron metal or ironcontaining minerals in the stone. The discolouration alters the appearance of the stone, which is undesirable from an aesthetic point of view. Despite rust staining being a conspicuous phenomenon and numerous works that have dealt with the problem of removing rust stains, a simple and non-toxic method has so far been missing. This paper describes a highly efficient method for cleaning rust stains from marble by introducing the chelating amino acid cysteine in a Laponite poultice in combination with the strong reducing agent sodium dithionite. Results: Cleaning experiments were performed on artificially discoloured samples of various types of Carrara Bianco marble and on naturally rust stained marble. To begin with, solutions of cysteine in combination with sodium dithionite and ammonium carbonate were tested by immersion of samples into the different solutions. Secondly, solutions of cysteine and sodium dithionite with and without buffering were used in a poultice consisting of Laponite® RD, Arbocel® BC1000 and CMC. The poultice was applied on three different marble types: Carrara Fabricotti, Carrara Vagli and Carrara La Piana. Thirdly, the optimized method was tested on original rust stained material of Greenlandic marble, which has been used as wall facing, and finally in situ in Copenhagen on a larger area of The Marble Church showing rust stains due to pyrite oxidation. The cleaning results were evaluated by visual observations, cross sections, and etching of the surface by testing on high gloss marble. Conclusion: Cleaning of iron-discoloured marble surfaces has been investigated and a new method for removal of rust stained marble has been developed. A solution of 0.1 M cysteine and 0.1 M sodium dithionite in a poultice consisting of Laponite® RD/Arbocel® BC1000/CMC = 10:10:1 has shown to be a fast, simple, cheap, and non-toxic, do-it-yourself method.
AB - Background: Calcareous materials, like marble used in connection with cultural heritage objects such as statues and pedestals, or as wall facings on buildings, often show a brownish staining owing to contact with iron metal or ironcontaining minerals in the stone. The discolouration alters the appearance of the stone, which is undesirable from an aesthetic point of view. Despite rust staining being a conspicuous phenomenon and numerous works that have dealt with the problem of removing rust stains, a simple and non-toxic method has so far been missing. This paper describes a highly efficient method for cleaning rust stains from marble by introducing the chelating amino acid cysteine in a Laponite poultice in combination with the strong reducing agent sodium dithionite. Results: Cleaning experiments were performed on artificially discoloured samples of various types of Carrara Bianco marble and on naturally rust stained marble. To begin with, solutions of cysteine in combination with sodium dithionite and ammonium carbonate were tested by immersion of samples into the different solutions. Secondly, solutions of cysteine and sodium dithionite with and without buffering were used in a poultice consisting of Laponite® RD, Arbocel® BC1000 and CMC. The poultice was applied on three different marble types: Carrara Fabricotti, Carrara Vagli and Carrara La Piana. Thirdly, the optimized method was tested on original rust stained material of Greenlandic marble, which has been used as wall facing, and finally in situ in Copenhagen on a larger area of The Marble Church showing rust stains due to pyrite oxidation. The cleaning results were evaluated by visual observations, cross sections, and etching of the surface by testing on high gloss marble. Conclusion: Cleaning of iron-discoloured marble surfaces has been investigated and a new method for removal of rust stained marble has been developed. A solution of 0.1 M cysteine and 0.1 M sodium dithionite in a poultice consisting of Laponite® RD/Arbocel® BC1000/CMC = 10:10:1 has shown to be a fast, simple, cheap, and non-toxic, do-it-yourself method.
KW - Arbocel
KW - Cleaning
KW - Cysteine
KW - Dithionite
KW - Laponite
KW - Marble
KW - Poultice
KW - Rust stain
UR - http://www.scopus.com/inward/record.url?scp=84977111796&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84977111796&partnerID=8YFLogxK
U2 - 10.1186/s40494-016-0081-6
DO - 10.1186/s40494-016-0081-6
M3 - Article
AN - SCOPUS:84977111796
VL - 4
JO - Heritage Science
JF - Heritage Science
SN - 2050-7445
IS - 1
M1 - 12
ER -