Photocatalytic TiO2 coatings on limestone

Licciulli, Antonio; Calia, Angela; Lettieri, Mariateresa; Diso, D.; Masieri, Maurizio; Franza, S.; Амаделли, Р.; Casarano, G.

doi:10.1007/s10971-011-2574-9

Cited by 60 publications

(34 citation statements)

References 22 publications

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“…Calcite is its principal constituent, along with very small quantities of clay and other non-carbonate minerals [23,24]. "Lecce stone" has a very high porosity, usually ranging from 30% to 45% [25][26][27], and has a unimodal porosity distribution. In our case, the used samples exhibited a porosity of 42%, with pore sizes mainly between 0.3 and 10 µm, as analysed by mercury-intrusion porosimetry [28].…”

Section: Methodsmentioning

confidence: 99%

Performances and Coating Morphology of a Siloxane-Based Hydrophobic Product Applied in Different Concentrations on a Highly Porous Stone

Lettieri

Masieri

2016

Coatings

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Many polymers, able to confer a hydrophobicity to treated surfaces, have been proposed for the restoration and conservation of civil and monumental buildings. Polysiloxanes, and their precursors, the silanes, have been frequently employed for stone protection. To avoid decay of the treated surfaces, the effectiveness and harmlessness of the treatment need to be carefully evaluated before application in the field. In this study, a commercial alkyl-siloxane was tested as a protective treatment on a highly porous stone, starting from water solutions with different contents of the product. The treatments have been devised to try to balance the requirements and the sustainability of the conservative actions. Sustainability, in terms of costs and environmental impact, is regarded as a key factor in the 21st century. Morphological observations of the stone surface, static contact angle and colour measurements, water vapour transmission test, and tests of water absorption were carried out to characterize the untreated and treated stones. A concentration below the minimum level suggested by the manufacturer was still able to act as a good barrier against water. More concentrated solutions produced polymer accumulation and coatings with extended cracks. The properties of the treated stone were affected by the presence of cracks in the coating.

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Section: Methodsmentioning

confidence: 99%

Performances and Coating Morphology of a Siloxane-Based Hydrophobic Product Applied in Different Concentrations on a Highly Porous Stone

Lettieri

Masieri

2016

Coatings

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“…From the section analysis the thickness of the coating formed by the aggregation of ultrafine TiO2 can be regarded as falling roughly into the 5-10 μm range (an example of measurement deduced from BSD image is given in Figure 2). The coating was homogeneously spread over stone but its surface was evidently cracked (Figure 2): this outcome may be related to the amount of TiO2 deposited and the subsequent thickness of the coating, over the critical thickness of crack development [29]. It is important to notice by the comparison of the SEM images reported in Figure 2 that cracks were not uniformly present all over the coating but they were present in a punctual manner.…”

Section: Microanalysis Of the Coatingmentioning

confidence: 93%

Preservation of Historical Stone Surfaces by TiO2 Nanocoatings

Goffredo¹,

Munafò²

2015

Coatings

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Abstract:We proposed the application of titanium dioxide (TiO2) for the preservation of historical (architectural, monumental, archaeological) stone surfaces. Solar light can activate the photocatalytic effect of TiO2 nanoparticles: heterogeneous photocatalysis is the key factor for the development of self-cleaning, depolluting and biocidal treatments able to photochemically degrade external damaging materials and prolong the durability of treated substrates, maintaining their original aspect and limiting ordinary cleaning activities. In this study, TiO2 nanoparticles dispersed in an aqueous colloidal suspension were applied directly on travertine, a light-colored limestone, by spray-coating in order to obtain a nanometric film on stone samples. To assess the feasibility of use of TiO2, we studied the characteristics of the nanocoating-stone system by monitoring the microscopic features of the coatings, the aesthetical changes induced to coated surfaces and the self-cleaning efficiency. We also monitored the self-cleaning ability over time during an accelerated ageing process to evaluate the durability of TiO2-based treatments. We confirmed both compatibility and effectiveness of TiO2 coating in the short term, anyway its efficiency decreased after artificial ageing. Further studies are necessary to better evaluate and eventually improve the stability of self-cleaning efficiency over prolonged time for outdoor stone surfaces.

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“…The samples were washed in distilled water, dried in an oven at 105 °C for at least 24 h to reach constant weight. After that, they were left to cool at room temperature and controlled RH 50%, then weighed again [40].…”

Section: Experimental Limestone Specimensmentioning

confidence: 99%

Performance of Clay, SiO2, Ca(OH)2 and CaCO3 - Polymeric Nanocomposites for Conservation and Preservation of Limestone Artworks

Aldoasri¹,

Darwish²,

Adam³

et al. 2018

Preprint

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Environmental deterioration factors are constantly increasing, causing unwanted aesthetic changes to stone artworks due to exposure to various physical and chemical deterioration factors. Inorganic nanoparticlefilled polymer composites have extended their multiple functionalities to various applications, including cultural heritage conservation. Therefore, this study has examined the effects of clay, SiO2, Ca(OH)2 and CaCO3 nanomaterials in the enhancement of the physicomechanical properties of limestone monuments, the aim of the present work being to evaluate comparatively the effectiveness of nanoparticles as consolidation and protection material for limestone artworks. The nanoparticles were added to an acrylic-based copolymer (polyethylmethacrylate (EMA)/methylacrylate (MA) (70/30), in order to improve its physiochemical and mechanical properties, and produced a significant improvement in the ability of the polymers to consolidate and protect the stone. The synthesis process of nanoparticles/polymer nanocomposite has been prepared by an in situ emulsion polymerization system. The nanocomposites contained poly (EMA/MA) with a solid content of 3% [poly (EMA/MA)] in the absence and presence of 5% nanoparticles (0.15 g nanoparticles). Samples were subjected to artificial aging by relative humidity/temperature and acid/salt crystallization weathering to show the optimum conditions of durability and the effectiveness of the nano-mixture in improving the physical and mechanical properties of the stone material. To ensure that the treatment had no negative effects on the physical characteristics of the limestone, the properties of the treated limestone samples were evaluated comparatively before and after artificial aging by the conduct of microstructural (phase morphology studied by means of scanning electron microscopy) and aesthetic (colour and lightness measured by spectrophotometry) analyses. Also used were measurement of static contact angle of water droplets on the surface of the samples, total immersion water absorption, compressive Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 7

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Photocatalytic TiO2 coatings on limestone

Cited by 60 publications

References 22 publications

Performances and Coating Morphology of a Siloxane-Based Hydrophobic Product Applied in Different Concentrations on a Highly Porous Stone

Performances and Coating Morphology of a Siloxane-Based Hydrophobic Product Applied in Different Concentrations on a Highly Porous Stone

Preservation of Historical Stone Surfaces by TiO2 Nanocoatings

Performance of Clay, SiO<sub>2</sub>, Ca(OH)<sub>2 </sub>and CaCO<sub>3</sub> - Polymeric Nanocomposites for Conservation and Preservation of Limestone Artworks

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