Industrial Methods for Capturing CO₂ from the Air<br />Assist. Prof. Malik Mustafa Mohammed<br /><br />The primary industrial approach to capturing carbon dioxide (CO₂) directly from the atmosphere is Direct Air Capture (DAC). This technology is critical for addressing diffuse emissions and achieving large-scale carbon removal. Below are the key methods and technologies: <br /> 1. Direct Air Capture (DAC) <br />DAC systems extract CO₂ directly from ambient air, unlike traditional carbon capture methods focused on point-source emissions (e.g., power plants). Key DAC technologies include: <br />a. Liquid Solvent Systems <br />- Process: Air is passed through a liquid chemical solution (e.g., amine-based solvents) that chemically binds with CO₂. The solvent is then heated to release concentrated CO₂ for storage or utilization.<br />- Example: While traditionally used for industrial exhaust, modified liquid solvent systems can adapt to atmospheric capture. <br />b. Solid Sorbent Systems <br />- Process: Advanced materials like polymers, metal-organic frameworks (MOFs), or engineered sorbents adsorb CO₂ from air. The Columbia University artificial tree exemplifies this approach, using sorbent-coated "leaves" to capture CO₂ at 1,000× the rate of natural trees. Captured CO₂ is later stripped via low-temperature processes, regenerating the sorbent.<br />- Advantages: Passive operation, high efficiency, and scalability. <br />c. Emerging DAC Technologies <br />- Membrane Separation: Selective membranes allow CO₂ to pass through while retaining other gases, though this method is less mature.<br />- Calcium Looping: Uses calcium oxide to react with CO₂, forming calcium carbonate. The material is later heated to release CO₂ and regenerate,<br /> 2. Complementary Industrial Approaches <br />While DAC is the primary method for air capture, other technologies indirectly reduce atmospheric CO₂ or enhance natural processes: <br />- Carbon Capture, Utilization, and Storage (CCUS): <br /> - Captures CO₂ from industrial point sources (e.g., cement plants) and stores it underground or repurposes it for products like concrete or synthetic fuels/<br /> - Post-Combustion Capture: Separates CO₂ from flue gases using solvents or adsorbents.<br /> - Oxy-Fuel Combustion: Burns fuel in pure oxygen to produce a CO₂-rich exhaust stream for easier capture.<br />- Mineralization: Accelerates natural weathering processes to convert CO₂ into stable minerals (e.g., via alkaline materials).<br /> Key Considerations <br />- Energy Use: DAC requires significant energy, often from renewables, to power air processing and CO₂ release. Innovations like passive designs (e.g., Columbia’s tree) aim to minimize this.<br />- Scalability: DAC systems must be deployed at massive scales (millions of units) to impact global CO₂ levels meaningfully.<br />- Cost: Current costs range from $100–$600 per ton of CO₂, but advancements in materials (e.g., Columbia’s sorbents) aim to reduce this.<br /> Conclusion <br />The most prominent industrial method for capturing CO₂ from air is Direct Air Capture (DAC), with technologies like liquid solvents, solid sorbents (e.g., Columbia’s artificial tree), and emerging methods like membranes. Complementary approaches like CCUS and mineralization further support atmospheric CO₂ reduction. Continued innovation in materials and energy efficiency will determine the scalability and affordability of these solutions. <br /><br />Al-Mustaqbal University – The No. 1 Private University in Iraq<br /><br />