One-step carbon capture and critical element recovery from mine tailings via carbonic anhydrase enhancement

Abstract

Mine tailings offer a promising resource for carbon dioxide (CO₂) sequestration through mineral carbonation. In this study, ten heterogeneous tailings from Northern Europe were evaluated as co-capture agents in an aqueous CO₂ system under mild conditions (25 °C, 1 atm, 20% CO₂), with and without an ultrastable carbonic anhydrase (DvCA8.0). The enzyme significantly accelerated CO₂ hydration, resulting in faster pH reduction and enhanced bicarbonate formation. Enzymatic systems achieved up to threefold higher CO₂ capture compared to controls, with maximum concentrations of 333.8 mg L⁻¹. Quantitative analysis showed that >80% of captured CO₂ originated from aqueous hydration, while mineral dissolution contributed <21%. Although experimental uptake remained below theoretical capacity, the results demonstrate the effectiveness of enzyme-assisted carbonation in complex mineral systems. Additionally, selective leaching of valuable elements, including rare earth elements, highlights the potential for simultaneous carbon capture and resource recovery.