Villani Elisa, Suzuki Amelia, Ricci Marilena, Salvadori Barbara, Vettori Silvia, Cantisani Emma
Institute of Heritage Science, National Research Council (CNR-ISPC), Via Madonna del Piano 10, 50019 Sesto Fiorentino (Florence), Italy.
Department of Earth Sciences, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy.
Analyst. 2024 Sep 23;149(19):4872-4880. doi: 10.1039/d4an00692e.
Stone cultural heritage buildings are frequently affected by different alteration phenomena and in particular, on heritage marbles the presence of chromatic discolouration, as the red stains, is one of the most widespread. In this paper, small fragments of red stains originated on marble exposed to different environmental contexts were analysed to reveal the presence and distribution of lead compounds at the micro-scale level. The samples come from slabs of historical religious buildings in Florence (Santa Maria del Fiore Cathedral and the San Giovanni Baptistery) and from the monumental fountains conserved in the Medicean Villa La Petraia (Florence). The presence and distribution of lead compounds: minium (PbO), carbonates such as cerussite (PbCO) and hydrocerussite (Pb(CO)(OH)) and plattnerite (PbO), was revealed using 2D high lateral resolution micro-X-Ray Powder Diffraction (μ-XRPD) and μ-Raman spectroscopy. Additional information were provided by Scanning Electron Microscopy, the elemental distribution performed with micro-X-Ray Fluorescence mapping enable to verify the possible presence of light elements and the use of FTIR chemical imaging confirmed the absence of organic compounds.
石材文化遗产建筑经常受到不同的蚀变现象影响，特别是在遗产大理石上，变色现象，如红色污渍，是最为普遍的现象之一。在本文中，对暴露于不同环境中的大理石上产生的红色污渍小碎片进行了分析，以揭示微观尺度上铅化合物的存在和分布情况。样本来自佛罗伦萨历史宗教建筑的石板（圣母百花大教堂和圣乔瓦尼洗礼堂）以及保存在美第奇家族的拉佩特拉亚别墅（佛罗伦萨）中的纪念性喷泉。使用二维高横向分辨率微X射线粉末衍射（μ-XRPD）和μ-拉曼光谱揭示了铅化合物的存在和分布，这些铅化合物包括铅丹（PbO）、碳酸铅矿（PbCO）和羟铅矿（Pb(CO)(OH)）以及块黑铅矿（PbO）。扫描电子显微镜提供了额外信息，用微X射线荧光映射进行的元素分布能够验证轻元素的可能存在，傅里叶变换红外光谱化学成像的使用证实了不存在有机化合物。
