Assessment of nanoparticles/nanocomposites to inhibit micro-algal fouling on limestone façades

ABSTRACT

This study conducted a comparison between biocide treatments based on nanoparticles of silver, copper, ZnO, TiO₂ and silver/ TiO₂ nanocomposites to analyse their capability to inhibit microalgal fouling on stone buildings. Biofouling is one of the main alterations on stone façades, causes degradation of their constituent materials and interferes with their aesthetic values. The proposed treatments were tested on a limestone from the historic quarry of Estepa (Spain), widely used as construction material in the South of Spain. The applicability of the treatments was evaluated by colorimetry. The biocidal effectiveness of the nanoparticles was studied on stone surfaces by multispectral imaging, digital image analysis and optical coherence tomography. This is a low-cost and efficient protocol to validate biocidal treatments for limestone monuments, and our results demonstrate the potential of silver and ZnO nanoparticles as a protective treatment for stone façades. The results have implications for practitioners working on historic buildings.

KEYWORDS:

• Deterioration
• aesthetics
• evaluation methods
• heritage
• anti-algae
• nanoparticle
• limestone

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Javier Becerra http://orcid.org/0000-0002-3360-4017

Pilar Ortiz http://orcid.org/0000-0002-8547-7531

Ana P. Zaderenko http://orcid.org/0000-0003-2504-9065

Ioannis Karapanagiotis http://orcid.org/0000-0002-2060-8721

Additional information

Funding

This study was partially supported by the following projects: BIA2015-64878-R (Art-Risk, RETOS project of the Ministerio de Economía y Competitividad  and Fondo Europeo de Desarrollo Regional), CTQ2013-48396-P (Ministerio de Economía y Competitividad and Fondo Europeo de Desarrollo Regional) and the research teams TEP-199, P10-FQM-6615 and FQM-319 from Junta Andalucía. J. Becerra is grateful to the Ministerio de Educación, Cultura y Deporte for his pre-doctoral fellowship (FPU14/05348), to the University Pablo de Olavide for funding his pre-doctoral research stay (Ref. AE-18-1) and to the University Ecclesiastical Academy of Thessaloniki for his stay as visiting researcher.