A multi-analytical approach to study the chemical composition of total suspended particulate matter (TSP) to assess the impact on urban monumental heritage in Florence

Colella

Malagodi

et al. 2021

Environ Sci Pollut Res

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The surface coating present on a marble Piety dating to the Renaissance period and stored at the Castello Sforzesco-Museum of Ancient Art (Milan, Italy) was studied and chemically characterised. For this purpose, both portable non-invasive (XRF and colorimetric measurements) and micro-invasive techniques (FTIR-ATR and SEM-EDS), have been applied. The statue has been recently submitted to a restoration, since its surface appeared dark and yellowed, before an exhibition at the Louvre Museum and the original appearance of the marble surface recovered thanks to the surface coating removal. Through the analytical characterisation carried out before and after the marble cleaning, the presence of a degradation layer composed by gypsum was evidenced on the stone. The origin of this layer is ascribable to the exposure of the statue to outdoor environment and interaction with atmospheric pollution. The chemical nature of the coating applied at the end of nineteenth century also responsible for the surface alteration was hypothesized.

Section: Resultsmentioning

confidence: 99%

Study of a surface coating present on a Renaissance Piety from the Museum of Ancient Art (Castello Sforzesco, Milan)

Colella

Malagodi

et al. 2021

Environ Sci Pollut Res

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“…The sulphatation process that commonly takes place in outdoor environments, can also bring to different forms of deterioration including black crusts formation (Gulotta et al 2013;Antonelli et al 2016;La Russa et al 2017;Comite et al 2017;Comite et al 2020b). However SO 2 is not the only component responsible for this degradation and other atmospheric pollutants such as black carbon and heavy metals are also involved (Fermo et al 2015;Fermo et al 2020b).…”

Section: Resultsmentioning

confidence: 99%

A multi-analytical diagnostic approach to study patinas, trace of colours and degradation process on the stone surface of a Renaissance Piety from the Museum of Ancient Art (Castello Sforzesco, Milan)

Colella

Malagodi

et al. 2021

Preprint

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Alteration dark patinas and traces of colours present on the surface of a marble Piety dating to the Renaissance period and stored at the Castello Sforzesco-Museum of Ancient Art (Milan, Italy) were studied and chemically characterized. For this purpose, a multi-analytical approach based on both portable non-invasive (XRF and colorimetric measurements) and micro-invasive techniques (FTIR/ATR and SEM-EDS), has been applied. The statue has been recently submitted to a restoration before an exhibition at the Louvre Museum and the original appearance of the marble surface recovered thanks to the patina removal. Through the analytical characterization carried out before and after the marble cleaning, the presence of a degradation layer composed by gypsum was evidenced on the stone surface. The origin of this layer is probably ascribable to the exposure of the statue to outdoor environment and interaction with atmospheric pollution. The chemical nature of the coating applied at the end of 19th century and responsible for the patina formation was hypothesized. Finally, the use of pigments originally applied by means of an organic binder was also highlighted.

“…Indeed, the historical buildings exposed in a polluted environment undergo degradation processes due to the interaction between atmospheric gases and stone surfaces. It is recognized that the presence of nitrate and chloride anions are attributable to atmospheric deposition; sulfate, instead, is produced by the degradation of the stone calcium carbonate due to the interaction with atmospheric SO 2 , thus also generating the so-called black crusts which are mainly composed of newly formed gypsum crystals, salts, and atmospheric particles (Comite et al 2020a(Comite et al , 2020b(Comite et al , 2020cFermo et al 2020). Hence, in the present work, the main anions (chloride, sulfate, and nitrate ones) were analyzed on both untreated and treated Candoglia marbles exposed at the Monza Cathedral.…”

Section: Application Of Polymeric Coatings Onto Candoglia Marble and Its Durability Upon Outdoor Exposurementioning

confidence: 99%

Calcitic-based stones protection by a low-fluorine modified methacrylic coating

Pargoletti

Comite

et al. 2021

Environ Sci Pollut Res

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Atmospheric pollutants, such as NOx, SO2, and particulate matter, together with water percolation inside the stone pores, represent the main causes of cultural heritage decay. In order to avoid these undesired phenomena, the application of protective coatings represents a reliable solution. In this context, the present study focused on the synthesis of low-fluorine content methacrylic-based (MMA) polymeric resins characterized by seven F atoms (namely F7 monomer) in the lateral chains. Four different percentages (1.0, 2.5, 5.0, and 10.0%) of the present monomer were adopted to obtain a final polymeric structure showing the desired hydrophobicity, processability, and structural and thermal stability (even after accelerated UV aging tests). MMA_F7(1.0) seemed to be the optimal one; therefore, it was further applied onto Candoglia marble. Specifically, the treated substrates showed good surface hydrophobicity, water repellency, and water vapor transpirability. No color variation was observed even after a 1.5-year exposure in a real polluted environment (Monza Cathedral). Interestingly, the application of this coating hindered the atmospheric nitrates penetration inside the stones and, at the same time, it limited the sulfates (gypsum) formation, thus revealing a very promising marbles protection resin.