A Novel Approach to CO₂ Geological Storage and Mineralization Using Bio-Based Biodegradable Chelating Agents

CO₂ geological storage and mineralization in mafic and ultramafic rock reservoirs has garnered significant global attention. However, the application of it has been hindered by challenges in reservoir properties and immature technologies, including potentially poor interconnected pore spaces, permeability, and rock reactivity, as well the difficulties in the use of seawater for CO₂ capture and uncontrollable carbonation. To address these issues, our research group proposed a new CO₂ capture, geological storage, and mineralization approach, with the innovative utilization of bio-based and biodegradable chelating agents and seawater. The approach involves injecting an acidic chelating agent solution to increase the effective porosity and permeability through chelating-agent-driven enhanced mineral dissolution. After that, alkaline GLDA-containing seawater is used to maximum CO₂ capture and storage efficiencies, which also maintains the injectivity by inhibiting the generation and crystallization of carbonates. Finally, the CO₂ mineralization process is controlled by modifying the biodegradation of the chelating agent. This study experimentally validates the effectiveness of using GLDA solutions in enhancing basalt dissolution, improving pore properties and permeability, and suggests optimal conditions for the implementation of this approach.