Investigation into the Gaseous SO2 Attack on Sandstone in the Yungang Grottoes
Investigation into the Gaseous SO2 Attack on Sandstone in the Yungang Grottoes
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DOI：
10.3390/min13010123
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发表时间：
2023-01
期刊：
影响因子：
2.5
通讯作者：
Yue Zhang;Cheng-Run Cao;H. Du;Jizhong Huang;Xiuwei Guo;Qin Luo;Jianguang Ren
中科院分区：
文献类型：
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作者：
Yue Zhang;Cheng-Run Cao;H. Du;Jizhong Huang;Xiuwei Guo;Qin Luo;Jianguang Ren
拥有1500多年历史的云冈石窟，自上个世纪以来一直受到空气污染的困扰。实地调查表明，酸性气体，特别是二氧化硫（SO2），已经积聚在雕塑的表面，造成各种类型的腐烂，降低了它们的艺术价值。为了进一步阐明气-岩相互作用过程，在实验室对当地砂岩进行了人工加速风化。在专门研制的试验装置中，新鲜试样在不同相对湿度和温度条件下暴露于气态SO2中。采用破坏性和非破坏性方法对云冈砂岩的物理、矿物学和化学变化进行了综合评价。结果表明：风化后，所有试样的光度都发生了变化，色调有轻微的向黄色变化。在老化循环过程中，重量有不同程度的增加，这既取决于物质的积累，也取决于粒子的脱离。较高的相对湿度和循环温度波动有利于碳酸盐的溶解和砂岩中长石的水解。随着时间的推移，样品近表面区域的离子浓度，特别是溶解的Ca2+和SO42−的浓度显著增加。在试验结束时，在一些样品中检测到新形成的石膏的痕迹。了解不同气候变量的协同影响将有可能确定复杂环境中砂岩退化的机制。
The Yungang Grottoes, with over 1500 years of history, have been subjected to air pollution since the last century. Field investigations have indicated that acid gases, particularly sulfur dioxide (SO2), have accumulated on the surface of the sculptures and caused various types of decay that reduce their artistic value. To shed new light on the gas–stone interaction process, artificially accelerated weathering was performed on local sandstone in the laboratory. In a specially developed test device, fresh specimens were exposed to gaseous SO2 under different relative humidity and temperature conditions. The physical, mineralogical, and chemical changes of Yungang sandstone were evaluated conjointly using destructive and non-destructive methods. The results show that after weathering, the luminosity of all specimens changed, with a slight alteration in hue toward yellow. The weight increased to various degrees during the aging cycles, which depended on both the accumulation of matter and the detachment of particles. Higher relative humidity and cyclic temperature fluctuations favored the dissolution of carbonates and the hydrolysis of feldspar in sandstone. The concentration of ions, especially dissolved Ca2+ and SO42−, increased considerably over time in the near-surface region of the specimens. A trace of newly formed gypsum was detected in some specimens at the end of the test. Knowing the synergistic impact of different climatic variables will make it possible to identify the mechanisms of the deterioration of sandstone in complex environments.