Carbonic Acid Could Be A Fix For Carbon

To reduce the threat of global warming, it has become a foregone conclusion that practical and inexpensive methods for trapping and sequestering carbon dioxide are needed. Current techniques include using solutions of amines to strip CO₂ from power-plant flue gases at high temperature and then pumping the CO₂ deep underground or to the bottom of the ocean. But that approach requires large amounts of chemicals and energy. A new candidate for CO₂ capture and sequestration could be carbonic acid, H₂CO₃, according to computational studies by John A. Tossell of the University of Maryland (Environ. Sci. Technol., DOI: 10.1021/es802393s). Although H₂CO₃ can be made by percolating CO₂ through water, the weak acid is unstable and has a fleeting existence in solution and as a solid. But under the right conditions, H₂CO₃ takes advantage of weak hydrogen bonds to form oligomers, (H₂CO₃)_n. Tossell took a closer look at available physical and spectral data on H₂CO₃ and made a series of calculations to determine that (H₂CO₃)_n for n = 2–4 could form a sufficiently stable solid from only CO₂ and water at low temperatures. Tossell is beginning to study the feasibility of low-cost, long-term CO₂ storage via H₂CO₃ at the Renewable Energy Institute at George Washington University.