Effect of biological colonization on ceramic roofing tiles by lichens and a combined laser and biocide procedure for its removal

  1. J. Pena-Poza 1
  2. C. Ascaso 2
  3. Sanz, M. 3
  4. S. Pérez-Ortega 4
  5. M. Oujja 3
  6. J. Wierzchos 2
  7. V. Souza-Egipsy, 5
  8. M.V. Cañamares 5
  9. M. Urizal 6
  10. M. Castillejo 3
  11. M. García-Heras 1
  1. 1 Instituto de Historia (CCHS-CSIC). Calle Albasanz 26-28. 28037 Madrid, Spain
  2. 2 Museo Nacional de Ciencias Naturales (MNCN-CSIC). Calle Serrano 115bis. 28006 Madrid, Spain.
  3. 3 Instituto de Química Física Rocasolano (IQFR-CSIC), Serrano 119, 28006 Madrid, Spain
  4. 4 Real Jardín Botánico ((RJB-CSIC). Plaza Murillo 2. 28014 Madrid, Spain
  5. 5 Instituto de Estructura de la Materia (IEM-CSIC). Calle Serrano 121. 28006 Madrid, Spain
  6. 6 Thor Especialidades SA. Barcelona, Spain
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Verleger: Zenodo

Datum der Publikation: 2019

Art: Dataset

CC BY 4.0

DOI: 10.5281/ZENODO.3531713 lock_openOpen Access editor

Zusammenfassung

Biodeterioration damage is an important issue in conservation and restoration of built heritage, especially when ceramic materials are used. Biological colonization of ceramic roofing tiles by lichens is a common phenomenon. However, there are no reports to date of lichens removal from unglazed roofing tiles for conservation purposes. This paper for the first time reveals the results of a combined procedure undertaken to assess the removal of lichens on different kinds of unglazed ceramic roofing tiles by treatments based on both dual sequential laser irradiation and treatment using Acticide<sup>® </sup>CF biocide. Three species of lichens were identified: <em>Verrucaria nigrescens</em>, <em>Calogaya decipiens</em> and <em>Pyrenodesmia teicholyta</em>. The chemical and mineralogical composition of roofing tiles were characterized by X-ray fluorescence (XRF) spectrometry, optical polarized petrographic microscopy, and X-ray diffraction (XRD). Laser irradiation was accomplished by applying sequences of nanosecond laser pulses at two wavelengths (1064 and 266 nm). After dual sequential laser irradiation a biocide was applied. To assess the combined effect of both treatments several techniques were used, including stereo and fluorescence (FM) microscopies, scanning (SEM) and transmission (TEM) electron microscopies, and FT-Raman spectroscopy. Chemical composition of the analyzed roofing tiles was shown as a relevant factor regarding the degree of interaction between the biological colonization and the substrate, and hence, the bioweathering effect. The combined procedure has proved to be very effective in damaging and mostly collapsing the lichen thalli without altering the substrate.