CO2 capture, geological storage, and mineralization using biobased biodegradable chelating agents and seawater.

Abstract

Geological storage and mineralization of CO2 in mafic/ultramafic reservoirs faces challenges including limited effective porosity, permeability, and rock reactivity; difficulties in using seawater for CO2 capture; and uncontrolled carbonation. This study introduces a CO2 capture, storage, and mineralization approach with the utilization of biobased biodegradable chelating agents and seawater. An acidic chelating agent solution is used to increase effective porosity and permeability through enhanced mineral dissolution. For instance, applying an acidic N,N-Bis(carboxymethyl)-L-glutamate solution to a porous basalt increased effective porosity by 16% and permeability by 26-fold in 120 hours. Subsequently, alkaline chelating agent-containing seawater improves CO2 capture and storage by inhibiting mineralization, thus maintaining injectivity while providing ions for mineralization and further expanding storage space. Last, controlled mineralization is achieved by adjusting chelating agent biodegradation. Promising CO2 storage and mineralization capacities two orders higher than current techniques, this approach reduces required reservoir volume while enhancing efficiency.