Evaluating the CO₂ Storage Potential of Scoriaceous Basalts in Saudi Arabia: Implications for the Saudi Green Initiative

While CO₂ mineralization is a crucial area of research for climate change mitigation, the potential of Saudi Arabian scoriaceous basalts has remained largely unexplored. In this study, we aim to assess these unique basalts as a potential CO₂ sink by conducting a longer aging study and, paving the way for Saudi Arabia and regions with similar geological formations to actively contribute to carbon sequestration and emission reduction, supporting sustainable development goals (SDGs) on Climate Action. Scoriaceous basalts were sourced from the Harrat Uwayrid volcanic field in western Saudi Arabia. To simulate CO₂ mineralization conditions, these samples were aged in a brine-CO₂ environment at 50°C and 1450 psi over three months. Advanced imaging techniques, including micro-CT and scanning electron microscopy (SEM), were employed to evaluate the mineralization potential and structural alterations within the basalt. Pre- and post-aging assessments provided detailed insights into the mineralization process occurring within the basalt groundmass, enabling a comprehensive understanding of the changes induced by CO₂ exposure. The Micro-CT analysis showed a significant increase in porosity for the scoriaceous basalt sample after three months in a brine-CO₂ environment, with porosity rising from an initial 5.72% to 14.89%. Furthermore, it showed that precipitation occurred along the sites of dissolution. SEM imaging showed clear signs of etching and dissolution, indicating the effective reactivity of these basalts with CO₂ under the aging conditions. These observations underscore that both dissolution and precipitation processes occurred, with ion release from basalt leading to stable carbonate formation and effective CO₂ trapping through mineralization. This investigation is a part of the study that was first to assess the scoriaceous basalts of Saudi Arabia for CO₂ storage, highlighting their distinct potential for CO₂ reduction. It also offers a foundational roadmap for future CO₂ sequestration projects, supporting the objectives of the Saudi Green Initiative.