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Graphene membranes with High Selectivity improve the efficiency of CO₂ capture
Context: Researchers at École Polytechnique Fédérale de Lausanne (EPFL) have recently unveiled innovative graphene membranes that could significantly enhance carbon capture efficiency. These membranes feature pyridinic nitrogen at their pore edges, aiding in the binding of CO₂ to the pores.
Advancing Graphene Membrane Performance for Carbon Capture:
- Objective: Enhance the separation performance of graphene membranes.
- Increase porosity in graphene, improve pore size distribution, and add polymer groups to the pores to improve CO₂/N₂ selectivity and achieve high CO₂ permeance.
- Simple Incorporation Process:
- Pyridinic nitrogen can be incorporated by soaking porous graphene in ammonia.
- This method significantly improves CO₂/N₂ selectivity while maintaining high permeance.
- Achieves extremely high CO₂/N₂ selectivity for dilute CO₂ feed, with factors above 1,000.
- Advantages of the Method:
- Atomic nitrogen introduced as pyridinic nitrogen has a high affinity for CO₂.
- The graphene lattice remains atom-thin, enabling both high selectivity and permeance.
- Challenges: Achieving both high permeance and high selectivity in graphene membranes was difficult.
- Developing high-performance and low-cost membranes for CO₂ capture.
- These challenges have limited the real-world application of carbon capture solutions.
- Future Implications:
- The developed graphene membranes and fabrication approach could enable large-scale carbon capture.
- Researchers are working on scaling up the membranes and simplifying fabrication with roll-to-roll synthesis for future commercialization.
Carbon Capture and Storage (CCS)
- CCS involves capturing CO2 emissions produced by industrial activities like power generation, hydrogen production, steel, or cement manufacturing. The captured CO2 is then transported and stored deep underground.
- It is a critical technology aimed at reducing carbon dioxide (CO2) emissions to combat global warming. It involves:
- Capture: CO2 is separated from other gases emitted during industrial processes such as coal or natural gas power plants, and steel or cement factories.
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- Involves the separation of CO₂ from mixed gas emissions.
- Captures CO₂ to prevent its release into the atmosphere.
- Utilises special membranes as selective barriers:
- Allows CO₂ to pass through and absorb it.
- Blocks the passage of other gases.
- Transport: The captured CO2 is compressed and transported via pipelines, road transport, or ships to a suitable storage site.
- Storage: CO2 is injected deep into geological formations underground, ensuring it remains permanently stored and does not re-enter the atmosphere.
- Role in Climate Action: CCS is crucial for achieving the goals of the Paris Agreement by helping to limit global temperature rise to 1.5°C. It is recognized as a technology that can complement efforts to reduce emissions by removing CO2 directly from the atmosphere.