Capturing carbon dioxide better with water repellent cotton balls

What is it about?

Carbon dioxide (CO₂) is a major cause of global climate change. As a result, many attempts have been made to capture and remove CO₂ from the air. One way to do it is to directly capture CO₂ from flue gas, the exhaust gas produced at power plants. This is done using porous materials decorated with amine, a compound we get from ammonia. However, their performance depends on the amount of moisture in the air. In fact, the amine makes these materials absorb moisture and get wet. For better performance, therefore, direct CO₂ capture must be independent of moisture. In this study, scientists came up with such a material. They first coated cotton balls with a chemically reactive coating. Then they decorated them with different amines to see which of them made the balls more “hydrophobic”, or water repellent. They found that turning the cotton balls more hydrophobic actually made them capture CO2 better. In fact, superhydrophobic (highly hydrophobic) cotton balls performed the best. They could trap CO₂ independent of moisture or CO₂ levels. However, superhydrophobic cotton without amine did not perform as well.

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Photo by Ella Ivanescu on Unsplash

Photo by Ella Ivanescu on Unsplash

Why is it important?

The CO₂ levels in our atmosphere are growing due to flue gas emissions. Trapping this CO₂ directly is our best chance of reducing CO₂ pollution. Earlier studies have shown that amine can help with direct CO₂ capture. However, the performance is poor at high moisture levels. This study shows that, for best performance, the capturing material must both contain amine and be superhydrophobic. KEY TAKEAWAY: Highly hydrophobic porous materials that contain amines show the best performance in direct CO₂ capture. These can be explored further to mitigate the effects of climate change.