Northwestern University Develops Low-Cost Carbon Capture Using Humidity and Sustainable Materials

Researchers at Northwestern University announced on April 3, 2025, a new, more affordable, and sustainable method for capturing carbon dioxide directly from the air. This innovative approach, called "moisture-swing direct air capture," uses humidity and readily available materials, offering a promising solution to combat climate change. The increasing levels of atmospheric carbon dioxide necessitate technologies that can reduce emissions in sectors that are difficult to decarbonize, such as aviation, agriculture, and construction. The moisture-swing carbon capture method stands out because of its low energy requirements, absorbing carbon dioxide in dry air and releasing it in humid conditions. Instead of expensive synthetic ion exchange resins, the Northwestern University team discovered that natural and inexpensive materials, including activated carbon, nanostructured graphite, carbon nanotubes, flake graphite and metal oxides like iron, aluminum, and manganese oxides, can perform effectively. These materials, often derived from waste or simple raw materials, are easier and cheaper to produce, making DAC technologies cheaper and more scalable. The researchers highlighted the importance of pore size in a material, noting that materials with medium pore sizes, ranging from 50 to 150 angstroms, performed optimally. With the right pore size and chemistry, these natural and inexpensive materials can rival or even surpass the effectiveness of ion exchange resins. This method can be implemented in many locations, providing an environmentally friendly solution without requiring significant additional energy. The research team aims to scale this method for everyday applications, making it a widespread solution. They are committed to assessing the environmental impact and costs associated with these new materials to provide a comprehensive understanding of their benefits to society.