Madrid. Engineers at the University of Illinois at Chicago (UIC) have created a cost-effective artificial leaf that can capture carbon dioxide at rates 100 times better than current systems.
Unlike other carbon capture systems, which work in laboratories with pure carbon dioxide from pressurized tanks, this artificial leaf works in the real world. It captures carbon dioxide from more dilute sources, such as the air and flue gases produced by coal-fired power plants, and releases it for use as fuel and other materials.
“Our artificial leaves can be implemented outside the laboratory, where they have the potential to play a significant role in reducing greenhouse gases in the atmosphere thanks to their high rate of carbon sequestration, relatively low cost and moderate energy, even at low temperatures. compared to the best systems” produced by man, Meenesh Singh, assistant professor of chemical engineering in the UIC School of Engineering and corresponding author of the paper, said in a statement.
The scientists modified a standard system of artificial leaves with inexpensive materials to include a gradient of water, a dry side and a wet side, across an electrically charged membrane.
On the dry side, an organic solvent binds to the available carbon dioxide to produce a bicarbonate or sodium bicarbonate concentration on the membrane. As it accumulates, the negatively charged ions pass through the membrane to a positively charged electrode in a water-based solution on the wet side of the membrane. The liquid solution dissolves the bicarbonate into carbon dioxide, so it can be released and used for fuel or other uses.
electrical charge
The electrical charge is used to accelerate the transfer of bicarbonate across the membrane.
When they tested the system, which is small enough to fit in a backpack, the UIC scientists found that it had a very high flux (a rate of carbon capture compared to the area required for reactions) of 3.3 millimoles per hour by 4 square centimeters. This is more than 100 times better than other systems, although only a moderate amount of electricity (0.4 KJ/hour) was needed to drive the reaction, less than the energy required for a one-watt LED light bulb. They estimated the cost at $145 per ton of carbon dioxide, which is in line with Department of Energy recommendations that it should not exceed $200 per ton.
“It’s exciting that this real-world application of an electrodialysis-driven artificial leaf had a high flux with a small modular surface area,” Singh said. “This means it has the potential to be stackable, modules can be added or removed to perfectly fit the need, and can be used affordably in homes and classrooms, not just among profitable industrial organisations. A small module the size of a domestic humidifier can remove more than a kilogram of carbon dioxide per day, and four industrial electrodialysis cells can capture more than 300 kilograms per hour of combustion gases.
The study was published in Energy & Environmental Science.
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