Effects of acidic attack on chemical, mineralogical, and morphological properties of geomaterials.

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.