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2024-11-23 17:57

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Conference: Bucharest University Faculty of Physics 2023 Meeting

Section: Solid State Physics and Materials Science, Optics, Spectroscopy, Plasma and Lasers

Title:

Efflorescence Formation and Interactions with Lithic Material: Insights from the Exterior Wall of the Episcopal Church – Curtea de Argeș

Authors:

Angel Theodor BURUIANA(1,2), Mohamed Yassine ZAKI(1), Florinel SAVA(1), Alin VELEA(1), Maria MARIN(3), Elena ISPAS(3), Alexandru Razvan PETRE(3), Corina Anca SIMION(3) and Anca LUCA(4)

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Affiliation:

1) National Institute of Materials Physics, 405A Atomiștilor Street, P.O. Box M.G. 7, Magurele 077125, Romania

2) Faculty of Physics, University of Bucharest, Atomistilor 405, 077125 Magurele, Romania

3) Horia Hulubei National Institute for Physics and Nuclear Engineering, 30 Reactorului Street, P.O. Box M.G. 6, Magurele 077125, Romania

4) University of Bucharest, Faculty of Geology and Geophysics, 6 Traian Vuia Street, Bucharest 020956, Romania

E-mail

angel.buruiana@infim.ro

Keywords:

Efflorescence, SEM-EDX, XRD, Raman spectroscopy, FTIR

Abstract:

Efflorescence, a phenomenon defined by the loss of water molecules from crystalline salts, has been studied on samples collected from an exterior wall of the Episcopal Church – Curtea de Argeș, during current restorations. The research aimed to: characterize the efflorescence and the lithic material using SEM-EDX (Scanning Electron Microscopy coupled with Energy Dispersive X-ray), XRD (X-Ray Diffraction), Raman and FTIR (Fourier Transform Infrared) spectroscopy analyses, but also estimate the impact of the efflorescence on the exterior walls preservation of the historical monument by radiocarbon determinations using AMS method. The efflorescence sample has two different zones, being predominantly composed of sodium carbonate crystallized with a minimum number of water molecules, a sign of the efflorescence phenomenon, and of calcium carbonate, respectively, indicating a mixture with recarbonated calcite arising from the interaction with lithic material. The lithic sample obtained by scraping the surface of limestone after discarding the efflorescence contains only calcium carbonate and rehydrated calcite, with no sodium compounds. To solve the interaction mechanisms between the wall, the efflorescence and the environment, a unique answer came from AMS method. As hypothesis to be tested, supposing that for treating of external walls between 2006 and 2017 a dietary sodium bicarbonate solution has been used, and knowing that the covering stone is quarry limestone, we can verify carbon-14 levels in both samples. Freshly cut limestone from the quarry has a geological origin and radiocarbon age at the lower limits of AMS dating. Dietary sodium bicarbonate has also been shown to have a geological age. Thus, Background levels were expected. Instead of, apparent ages were: 30,000 years and 10,000 years, respectively, as a result of succesive-layers combination with carbon dioxide from atmosphere. Radiocarbon dating and FTIR results demonstrates the occurrence of decarbonation/recarbonation at the interface between efflorescence and lithic material, further research being required.

Acknowledgement:

NIMP authors acknowledge funding by the Core Program of the National Institute of Materials Physics, granted by the Romanian Ministry of Research, Innovation and Digitization through the Project PC3-PN23080303.