Carbon Capture Technologies The most mature technology for removing CO₂ from industrial flue gases is chemical absorption using aqueous amines (e.g., monoethanolamine). While effective, this process is energy-intensive due to the heat required for solvent regeneration and poses environmental risks via the formation of toxic secondary emissions like nitrosamines.

To address these limitations, significant innovations are emerging:

• Advanced Materials: The 2025 Nobel Prize in Chemistry was awarded to Richard Robson, Susumu Kitagawa, and Omar Yaghi for developing Metal-Organic Frameworks (MOFs). These porous, crystalline materials offer tunable structures for highly selective and energy-efficient gas capture. Other solid adsorbents like zeolites are being optimized for separating CO₂ from N₂ or CH₄ via equilibrium and steric effects.

• Electrochemical Methods: New electrochemical CO₂ capture (ECC) technologies, such as pH-swing cycles and redox-active carriers (e.g., quinones), allow for CO₂ separation using electricity rather than heat. Recent breakthroughs include pH-independent redox chemistries that significantly lower thermodynamic energy costs.

• Biomimetic Approaches: Researchers have engineered thermostable Carbonic Anhydrase (CA) enzymes that can withstand harsh industrial conditions (temperatures >100°C), accelerating CO₂ hydration and mineralization rates.

Geological Storage Captured CO₂ is typically compressed into a supercritical fluid and injected into deep geological formations (saline aquifers, depleted oil/gas fields). Security relies on four trapping mechanisms: structural (trapped by caprock), residual (trapped in pores), solubility (dissolved in brine), and mineral (reacted to form solid carbonates). Geochemical interactions between CO₂, brine, and rock are critical; for instance, mineralization offers permanent storage but is a slow process that can be accelerated by enzymes or reactive silicates.

Controversies and Challenges A major 2025 study published in Nature challenges industry projections, suggesting the global capacity for safe geological storage is 10 times lower than previously estimated due to leakage risks and geological limitations. However, some experts argue this high-level analysis may overlook detailed regional capacities and successful pilot projects. Additionally, amine degradation products remain a regulatory concern, requiring careful monitoring of emissions.

Future Frontiers The field is moving toward integrated capture and conversion, where captured CO₂ is directly electrochemically reduced into valuable fuels (e.g., methane, ethylene) or chemicals (e.g., formate), bypassing the energy-intensive desorption step