What are some promising carbon sequestration methods?
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By Darko Savic on Sep 01, 2020
Direct Air Capture and Sequestration (DACS)
Though many physicochemical technologies are being tried and tested to sequester the floating carbon (in the form of oxides, mostly carbon-dioxide), Direct Air Capture and Sequestration technology seems like the most efficient and promising one. In DAC, synthetic sorbents are used to capture the atmospheric CO2 directly. This is a chemical process, and the sorbents used are in the form of amines, alkali/alkaline earth metal oxides, polymers and similar molecules that can interact with the CO2 in the air and capture it. The process directly removes the atmospheric CO2 by using scrubbers and produces concentrated CO2 as the end product, which will be sequestered or used for other purposes in future. The scrubbing process makes use of either adsorption (surface attachment) or absorption (matrix-entrapment) or both, or specialized membranes. Though this process might seem similar to another sequestration technique called Carbon Capture and Sequestration (CCS), DAC differs from CCS in that the point source of CO2 extraction is atmospheric air rather than concentrated point sources like coal-fired power plants, chemical plants, etc. As of 2020, this technology has been pioneered into a pilot-scale operation by Carbon Engineering, a Canada based environmental technology company. As they claim, the technology is industrially scalable and affordable. On top of that, the technology is deemed to capture CO2 from the air in a closed "chemical loop" that makes it possible for the same capture chemicals to be reused over and over. The closed-loop process os non-volatile, ensuring a minimal amount of wastage. See the video below to see how the technology works: https://www.youtube.com/watch?v=GkEAA7VnyhE Read this paper to see the fundamental scientific and engineering details of the technology: https://www.sciencedirect.com/science/article/pii/S2542435118302253
by Subash Chapagain on Sep 07, 2020