Global warming is getting increased day by day that poses a potential threat to environment leading to melting of ice caps and submergence of low-lying areas. This can be attributed to increased CO2 levels in the released in the atmosphere as a result of urbanization and industrialization. Scientists are coming up with innovative solutions to counter the drastic effects of Global warming.
They are looking to come up with methods that not only decrease the production of carbon dioxide (CO2) but also ways to capture the released carbon dioxide. Researchers at Penn state university have developed a rechargeable battery called flow cell that can be recharged using water based solutions containing dissolved carbon dioxide (CO2) and ambient air. The device generates electricity based on the CO2 concentration differences between the CO2 emissions and ambient air.
How does flow cell function?
-Initially, the researchers dissolved carbon dioxide and ambient air in aqueous solutions in separate containers - a process called sparging.
-The solution with dissolved CO2 has higher pH than the solution containing ambient air.
Researchers then injected the solutions into one of the two channels in a flow cell creating a pH gradient.
-The two containers contain electrodes and are separated by a semi-porous membrane that does not allow solutions but allows only ions to pass through it.
-Due to pH gradient between solutions ions pass across the membrane and a voltage difference is created between two electrodes.
-As a result, electrons flow through the wire connects to the electrodes and thereby generates electricity.
After the flow cell is discharged it can be recharged again by switching the channels that contain solutions, the same mechanism follows but the direction of flow of electrons is reversed. By constant switching, researchers observed that the fuel cell maintained the performance for 50 cycles. So, higher the pH gradient more will be the electricity generation.
PH gradient flow cell generates power density higher compared to similar cells that convert waste CO2 into electricity but lower than the power density of fuel systems that combine CO2 with other cells such as Hydrogen (H2). But the flowcell offers advantages over other devices. It is inexpensive and can be operated at room temperatures whereas other methods will need higher temperatures for the operation and costly. The scientists are now looking to optimize the solution conditions to further increase the generation of electricity.
The Research study is published in the journal Environmental Science and technology letters
The Research study is published in the journal Environmental Science and technology letters
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