Adsorbent Materials for Carbon Dioxide Capture from Large Anthropogenic Point Sources

Abstract

Since the time of the industrial revolution, the atmospheric CO₂ concentration has risen by nearly 35 % to its current level of 383 ppm. The increased carbon dioxide concentration in the atmosphere has been suggested to be a leading contributor to global climate change. To slow the increase, reductions in anthropogenic CO₂ emissions are necessary. Large emission point sources, such as fossil-fuel-based power generation facilities, are the first targets for these reductions. A benchmark, mature technology for the separation of dilute CO₂ from gas streams is via absorption with aqueous amines. However, the use of solid adsorbents is now being widely considered as an alternative, potentially less-energy-intensive separation technology. This Review describes the CO₂ adsorption behavior of several different classes of solid carbon dioxide adsorbents, including zeolites, activated carbons, calcium oxides, hydrotalcites, organic–inorganic hybrids, and metal-organic frameworks. These adsorbents are evaluated in terms of their equilibrium CO₂ capacities as well as other important parameters such as adsorption–desorption kinetics, operating windows, stability, and regenerability. The scope of currently available CO₂ adsorbents and their critical properties that will ultimately affect their incorporation into large-scale separation processes is presented.