Iron stains on paper. Can electrophoretic removal become an effective alternative to chemical cleaning?

Abstract

Research in restoration and conservation is directed vs. more sustainable working materials, methods and technologies. Electrophoretic removal, from porous material, of undesired stains due to charged species is theoretically an interesting alternative to chemical cleaning methods, but the lack of specific and comprehensive research work leads to controversial opinions about the efficiency and the needed harmfulness for the treated objects. In this work paper, samples with artificial rust stains were subjected to electrophoretic cleaning treatments in mineral water as electrolyte. Treatments were carried out either in a bath by complete sample immersion between the distanced electrodes or by sample wetting and sandwiching between the electrodes. Evaluation of cleaning efficiency and treatment effects was based on colour change measurements (image analysis of scanned paper samples before and after the treatment and by colorimetric data via spectrophotometric measurements), investigation of morphological changes by SEM observations and folding endurance measurements.

Keywords:

• Electrophoresis
• iron stains
• paper
• green chemistry
• restoration
• cultural heritage

Acknowledgements

The sincere thanks to everyone who participated with great enthusiasm and encouragement in this research. Especially, Professors Daniela Ferro, Stella Nunziante Cesaro and Marcello Colapietro, respectively, for the SEM-EDS, microFTIR and XRD analysis. To Drs Maria Teresa Tanasi, Loredana Botti and Maria Luisa Riccardi of the Central Institute for the Restoration and Preservation of the Archival and Library Heritage (ICRCPAL) for the folding endurance measurements, for having clarified some doubts and for giving us some hints for the research.