Calcium Oxalate on Limestone Surface of Heritage Buildings

Abstract:

In this paper, the presence of calcium oxalate on calcareous stone, is studied. The patina consists mainly of calcium oxalate which exists in three forms: monohydrated whewellite (small, smooth, globular yellow-green to brown crystals radial fibrous) (COM), dehydrated weddelite (small crystals, and spherical clusters of plaques consisting of brown or yellow platelets, which are sharp) (COD) and trihydrate caoxite (rarely observed, as mono or dihydrated precursor forms)(COT). Scanning electron microscope with Energy Dispersive X-ray Spectroscopy (SEM/EDS), Fourier Transform Infrared spectroscopy (FTIR), Raman Spectroscopy are used for characterization. The oxalate films were found to form a thin compact non-porous shell and penetrate deeply in an intergranular position or along microfractures, with effects on longer stability.

• Periodical: Key Engineering Materials (Volume 750)
• Pages: 129-134
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.750.129
• Online since: August 2017
• Authors: Rodica Mariana Ion*, Sofia Teodorescu, Raluca Maria Ştirbescu, Ioan Alin Bucurică, Ioana Daniela Dulamă, Mihaela Lucia Ion
• Keywords: Calcium Oxalate, COD, Com, COT, FTIR, RAMAN, SEM

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