Abstract

The cleaning or removal of manganese stains on Cultural Heritage has not been much tested or successful so far. The aim of this article was to assess a new green cleaning gel for Mn-rich black-blue stains on different substrates. The black-blue stains were characterized at optical and chemical level through colour-related data, optical microscope, FTIR, XRF and XPS. Mn-stained granite found on historical churches at Vila Real (North of Portugal) and glass jars of Leclanché cells, belonging to the ISEP’s Museum (Portugal) collection, were the ideal case studies to test the efficiency of chitosan: thiourea dioxide (TD) cleaning gel. TD proved to be the best candidate to reduce insoluble manganese oxides, over Hydroxylamine Hydrochloride and Hydroxymethanesulfinic Acid. Cleaning assays performed on stained granite samples collected at a historical quarry and in situ application on stained granite churches allowed removal of the stains to a satisfactory level. Similar results were obtained on stained glass jars.

Details

Title
Green chitosan: thiourea dioxide cleaning gel for manganese stains on granite and glass substrates
Author
Campos, Bruno 1 ; Marco, Alexandra 1 ; Cadeco Guilhermina 2 ; Freire-Lista, David M 3 ; Silvestre-Albero Joaquin 4 ; Algarra Manuel 5 ; Vieira Eduarda 6 ; Pintado Manuela 7 ; Moreira Patrícia 1   VIAFID ORCID Logo 

1  Universidade Católica Portuguesa, Research Centre for Science and Technology of the Arts, Porto, Portugal (GRID:grid.7831.d) (ISNI:000000010410653X); Universidade Católica Portuguesa, Centre for Biotechnology and Fine Chemistry, Porto, Portugal (GRID:grid.7831.d) (ISNI:000000010410653X) 
2  Museu do Instituto Superior de Engenharia do Porto- Instituto Politécnico do Porto, Porto, Portugal (GRID:grid.410926.8) (ISNI:0000 0001 2191 8636) 
3  Universidade de Trás-os-Montes e Alto Douro, Vila Real, Portugal (GRID:grid.12341.35) (ISNI:0000000121821287); Centro de Geociências. Universidade de Coimbra, Coimbra, Portugal (GRID:grid.8051.c) (ISNI:0000 0000 9511 4342) 
4  Universidad de Alicante, Departamento de Química Inorgánica, Alicante, Spain (GRID:grid.5268.9) (ISNI:0000 0001 2168 1800) 
5  Universidad de Málaga, Departamento de Química Inorgánica, Málaga, Spain (GRID:grid.10215.37) (ISNI:0000 0001 2298 7828) 
6  Universidade Católica Portuguesa, Research Centre for Science and Technology of the Arts, Porto, Portugal (GRID:grid.7831.d) (ISNI:000000010410653X) 
7  Universidade Católica Portuguesa, Centre for Biotechnology and Fine Chemistry, Porto, Portugal (GRID:grid.7831.d) (ISNI:000000010410653X) 
Publication year
2021
Publication date
Dec 2021
Publisher
Springer Nature B.V.
e-ISSN
20507445
Source type
Scholarly Journal
Language of publication
English
DOI
https://doi.org/10.1186/s40494-021-00632-y
ProQuest document ID
2610662007
Copyright
© The Author(s) 2021. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.