The article discusses the use of low-pressure plasma etching to inhibit biodegradation on building limestone surfaces. The study aimed to investigate the effectiveness of plasma etching in removing microbials from bio-deteriorated limestone surfaces in monuments and buildings to provide conservators with a viable preservation solution.
The research was conducted at the Batalha Monastery in Portugal, a UNESCO World Heritage site suffering from severe biodeterioration due to lichenous crusts and microorganism biofilms. The plasma etching process involved treating stone tablets with various parameters of coupled-capacitive plasma to assess the cleaning results.
Results indicated that plasma etching efficiently removed sugar compounds from limestone surfaces, preventing microorganism growth by eliminating their main nutrient supplies. Plasma treatment damaged microorganisms by disrupting cell structures, leading to the removal of filamentous microbes, rupture of circular microbial cells, and detachment of biofilm. Cell viability tests showed that plasma treatment with different parameters resulted in significantly reduced cell viability compared to untreated samples, with the lowest viability observed under specific plasma conditions.
Overall, the study demonstrated that plasma etching is a promising method for cleaning and preserving limestone surfaces in historical buildings and monuments. By effectively removing microbial contamination and inhibiting biodegradation, plasma etching offers a feasible and efficient solution for conserving stone monuments in urban and rural environments. The research findings contribute to the development of innovative techniques for cultural heritage conservation and highlight the potential of plasma technology in the field of architectural surface cleaning and preservation.
