Black soiling of an architectural limestone during two-year term exposure to urban air in the city of Granada (S Spain)

Urosevic, Maja; Yebra‐Rodríguez, África; Sebastián-Pardo, Eduardo; Cardell, Carolina

doi:10.1016/j.scitotenv.2011.11.028

Cited by 64 publications

(43 citation statements)

References 48 publications

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“…TEM-EDX analysis reveals that all the nanostructures predominantly contain O, Si, Al, Fe and little amounts of Mg, K, Ti, Ca, S, P etc. This composition is very similar to the one of glassy fly-ashes originating from coal combustion plants [13,14,17,27,28], being described as 2 -40 µm glassy aluminosilicate spheres containing Mg, Fe, Ti, K as other elements [19,27]. More specifically, the nanostructures of interest in the present study have a composition close to that of the so-called magnetospheres or ferrospheres, a particular type of coal fly ashes which are magnetic and enriched in iron [29].…”

Section: Discussionsupporting

confidence: 66%

Laser yellowing effect: study of the nanophases created by laser irradiation of synthetic black crusts using transmission electron microscopy (TEM) and electron paramagnetic resonance (EPR) spectroscopy

Godet¹,

Vergès‐Belmin²,

Saheb³

et al. 2017

Proceedings of the International Conference LACONA XI

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Nd:YAG Q-Switched laser cleaning at 1064 nm can sometimes lead to a more yellow appearance of the stone surface in comparison with other cleaning techniques. The yellow hue can originate from different contributions among which the presence of nano-sized residues generated by the laser interaction with the surface materials to be eliminated. In this study, the nature of such residues has been investigated. The analyzed materials are (i) particles collected from a pure gypsum reference plate; (ii) a synthetic crust, composed of 80 wt % natural black crust and 20 wt % synthetic gypsum; (iii) particles ejected from the synthetic crust during laser irradiation. Optical, scanning electron and transmission electron microscopies were used to link color changes at the macro-scale to morphology changes at the submicron-and nano-scales. Chemical composition was also obtained at the nano-scale using TEM coupled with energy dispersive X-ray (EDX) spectroscopy. This multi-scale approach was combined with electron paramagnetic resonance spectroscopy (EPR) analysis at low and room temperatures to examine the possible presence of iron-containing species presenting particular magnetic properties in the sample before and after irradiation. Under laser irradiation, both the crust sample and the ejected gypsum particles take a yellow color. This color shift can be linked with morphology changes occurring at the nano-scale: gypsum crystals from the reference plate show a smooth surface, while those coming from the synthetic black crust are, after irradiation, covered by many spherical nanoparticles and a rough nano-layer ranging from less than 20 nm to more than 100 64Marie Godet et al.nm. TEM-EDX analysis reveals that the two types of nanostructures have a chemical composition very similar to that of iron-rich coal fly-ashes called magnetospheres or ferrospheres. It is suggested that laser irradiation induces a transformation of micrometric size fly-ashes present in the black crust into different types of nanostructures having a chemical composition similar to the one of ferrospheres. EPR analysis demonstrates the presence of ferri-ferro-superparamagnetic species both before and after irradiation, thus indicating that nanosized magnetic iron compounds probably corresponding to magnetite or maghemite oxides are present in the black crust, most probably crystallized on the surface or within the fly-ashes microparticles. This study brings to light the contribution of fly-ashes to the laser induced yellowing process.

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Section: Discussionsupporting

confidence: 66%

Laser yellowing effect: study of the nanophases created by laser irradiation of synthetic black crusts using transmission electron microscopy (TEM) and electron paramagnetic resonance (EPR) spectroscopy

Godet¹,

Vergès‐Belmin²,

Saheb³

et al. 2017

Proceedings of the International Conference LACONA XI

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“…One of the key problems of external use is the discoloration of building facades. The colour changes can be attributed to air pollution, in the form of deposition of pollutants which lead to blackening of building stone (Bonazza et al, 2005;Grossi and Brimblecombe, 2007;Urosevic et al, 2012). The blackening process clearly related to particulate matter (Amoroso and Fassina, 1983).…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Discoloration Generated by a CI ICE's Exhaust Gas on Various Stone Types

Farkas

Szabados

Antal

et al. 2018

Period. Polytech. Transp. Eng.

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“…Por otro lado la formación de costras negras es un proceso de degradación especialmente importante en entornos urbanos donde la mezcla de partículas procedentes de la combustión de combustibles fósiles junto con otra variedad de factores como el polvo, la fauna microbiana, etc. (Watt et al, 2009) favorecen la formación de costras de yeso (Urosevic et al, 2012). También, la colonización bioló-gica juega un papel fundamental en el deterioro (SaizJiménez y Ariño, 1995).…”

Section: Introductionunclassified

Characterization and main pathologies of the sandstone “Piedra Dorada” used in historic buildings in the cities of Úbeda and Baeza (Jaén, southern Spain)

Gisbert¹,

Navarro²,

Sánchez-Valverde³

et al. 2017

Bol. geol. min.

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Black soiling of an architectural limestone during two-year term exposure to urban air in the city of Granada (S Spain)

Cited by 64 publications

References 48 publications

Laser yellowing effect: study of the nanophases created by laser irradiation of synthetic black crusts using transmission electron microscopy (TEM) and electron paramagnetic resonance (EPR) spectroscopy

Laser yellowing effect: study of the nanophases created by laser irradiation of synthetic black crusts using transmission electron microscopy (TEM) and electron paramagnetic resonance (EPR) spectroscopy

Experimental Investigation of Discoloration Generated by a CI ICE's Exhaust Gas on Various Stone Types

Characterization and main pathologies of the sandstone “Piedra Dorada” used in historic buildings in the cities of Úbeda and Baeza (Jaén, southern Spain)

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