Antifungal activity of Ca[Zn(OH) sub(3)] sub(2) times 2 H sub(2)O coatings for the preservation of limestone monuments: An in vitro study

The antifungal properties of protective coatings based on Ca[Zn(OH) sub(3)] sub(2) times 2 H sub(2)O have been evaluated both on glass slides and on three different limestone materials, which have regional significance as the most commonly used building and restoration materials in the region, inclu...

Full description

Saved in:
Bibliographic Details
Published in:International biodeterioration & biodegradation 2014-07, Vol.91, p.1-8
Main Authors: Gomez-Ortiz, N M, Gonzalez-Gomez, W S, De la Rosa-Garcia, S C, Oskam, G, Quintana, P, Soria-Castro, M, Gomez-Cornelio, S, Ortega-Morales, B O
Format: Article
Language:English
Subjects:
Aspergillus niger
Calcium
Coatings
Construction materials
Fungi
Illumination
Limestone
Penicillium oxalicum
Protective coatings
Scanning electron microscopy
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The antifungal properties of protective coatings based on Ca[Zn(OH) sub(3)] sub(2) times 2 H sub(2)O have been evaluated both on glass slides and on three different limestone materials, which have regional significance as the most commonly used building and restoration materials in the region, including for historic Mayan monuments and artifacts. The protective coatings were found to have excellent antifungal properties, inhibiting the growth of Penicillium oxalicum and Aspergillus niger, both in the dark and under illumination. Experiments were carried out at a laboratory test site under simulated photoperiod conditions, consisting of 24-h cycles of 12 h in the dark and 12 h under illumination: 21 days after inoculation and exposure to photoperiod conditions, no fungal growth was observed for any type of limestone, for both fungi. X-ray diffraction illustrated that the formation of calcium oxalate in the weddellite structure is an indicator of the fungal activity. Close inspection of samples with scanning electron microscopy (SEM) revealed that for all limestone substrates without protective coating, fungal growth was observed as well as fungal penetration into the limestone material. SEM images also show that the Ca[Zn(OH) sub(3)] sub(2) times 2 H sub(2)O coating is well-adhered to all substrates, without the presence of significant cracks in the coating. For the three limestone substrates with the protective coating, no fungal growth was observed, illustrating the excellent antifungal properties of the calcium zinc hydroxide dihydrate material.
ISSN:0964-8305
DOI:10.1016/j.ibiod.2014.02.005