Graduate Program in Environmental Science and Technology, Federal University of Fronteira Sul, ERS 135, km 72, no 200, Erechim, RS, 99700-970, Brazil.
Graduate Program in Civil and Environmental Engineering, University of Passo Fundo, BR 285, km 292, Passo Fundo, RS, 99052-900, Brazil.
Environ Sci Pollut Res Int. 2020 Oct;27(30):37718-37732. doi: 10.1007/s11356-020-09834-6. Epub 2020 Jun 30.
Exposure of geomaterials to acidic leachates may compromise their structure and functionality due to changes in physicochemical, mineralogical, and hydraulic behavior. The literature identifies the need to evaluate changes in a pure state and in conditions of extreme acidity. This study aimed to evaluate changes in the chemical, mineralogical, and morphological properties of Osorio fine uniform sand (OFS), basalt residual soil (BRS), kaolin (KAO), and bentonite (BEN) exposed to sulfuric acid in concentrations of 0.00 mol/L (distilled water), 0.01 mol/L, and 1.00 mol/L. The tested samples were characterized using X-ray fluorescence spectrometry, X-ray diffraction, thermogravimetry, differential scanning calorimetry, and scanning electron microscopy. The acid attack on geomaterials by contact with the solution 1.00 mol/L has resulted in the solubilization of some constituent minerals, as well as the formation of sulfate minerals, changes in the water dehydration peak in the pores, and mass loss. The morphology of the sand and bentonite particles did not change with exposure to sulfuric acid. The acidic attack resulted in changes in the morphology of the particles for BRS and KAO. The results of this study are important for determining operational parameters of waste containment systems and contaminated areas, as well as for applying geomaterials as founding materials.
岩土材料暴露于酸性浸出液中可能会因其物理化学、矿物学和水力行为的变化而破坏其结构和功能。文献指出需要在纯净状态和极端酸性条件下评估这些变化。本研究旨在评估奥索里奥细均砂（OFS）、玄武岩残积土（BRS）、高岭土（KAO）和膨润土（BEN）在 0.00 mol/L（蒸馏水）、0.01 mol/L 和 1.00 mol/L 硫酸浓度下暴露于酸性条件后化学、矿物学和形态特性的变化。使用 X 射线荧光光谱法、X 射线衍射法、热重分析、差示扫描量热法和扫描电子显微镜对测试样品进行了表征。与溶液接触的酸对岩土材料的侵蚀导致一些组成矿物的溶解，以及硫酸盐矿物的形成、孔隙中水脱除峰的变化和质量损失。与硫酸接触后，砂和膨润土颗粒的形态没有变化。BRS 和 KAO 颗粒的酸性侵蚀导致其形态发生变化。本研究结果对于确定废物封存系统和污染区域的操作参数以及将岩土材料用作基础材料具有重要意义。
