Electrokinetic Property and Colloidal Stability Study of Igneous Rocks: Implication on Carbon Mineralization and Underground CO₂ Storage

The reduction of carbon footprints is one of the steps being taken as the world looks for a solution to the difficulties caused by climate change. This will be accomplished by developing technologies that both consume and emit less carbon dioxide into the atmosphere. Other methods include mineralization or bulk storage of the captured gases in subsurface reservoirs. Mineralization involves the interaction of cation-rich rocks or fluids with carbonated water to form precipitates that ensure the safe disposal of CO₂ that has been captured. To assess the viability of this route, numerous initiatives have been made as well as a few experimental projects. Understanding of the electrokinetic property of igneous rocks, which governs characteristics like wetting conditions and susceptibility to release cations, is, however, rare in the literature. Thus, to shed light on the electrokinetic behavior and colloidal stability of igneous rocks, this research has employed electrophoresis. This research revealed that igneous rocks are mainly negatively charged in both freshwater and saltwater environments. On the other hand, igneous rocks’ magnesium ion content significantly affects how they are charged, occasionally flipping the charge to positive and shifting the solution state from acidic to alkaline. This would have an even greater effect on the mineralization process and shorten the time needed for the reaction between igneous and CO₂-rich fluids. This is inferred by the fact that the highest dissolution of metal cations is known to occur at pH values of 3 and 4. Furthermore, samples with a low magnesium content have stable colloidal stability, whereas samples with a high magnesium content are colloidally unstable. The samples’ colloidal stability also has a significant impact on how easily the cations needed for mineralization are released.