1403239 / 1403298 Collaborative Research: Characterizing Interactions of Carbon Dioxide with Tailored Adsorbing Materials for Capture of Carbon Dioxide from Power Plant Exhaust Gas and Ambient Air
Capturing CO2 from ambient air, or air capture, has significant technical challenges. The concentration of CO2 in air (~ 400 ppm) is far less than the CO2 concentrations in other applications such as post-combustion flue gas treatment. Any air capture process must use minimal amounts of energy, ideally from a distributed renewable source such as solar thermal energy. To apply air capture or conventional Carbon Capture Utilization and Storage (CCUS) on large scales, low cost and highly durable materials are required.
Tailored carbon dioxide adsorbents that combine nitrogen-bearing chemicals on solid sponge-like supports are perhaps the only class of adsorbents that might be practical for air capture applications. These materials are also important in CO2 removal from flue gases. These gas separation processes require a material to selectively removes CO2 (leaving other species behind) in the temperature range of 0-65 C, and in an environment where water is ubiquitous. Under these conditions, many types of adsorbents can be effectively ruled out. Some (physisorbents) will not effectively adsorb CO2 under these conditions because water competes with the carbon dioxide for sites within the material. Some other chemical types (chemisorbents) require high temperature operating conditions.
In contrast,the PIs propose to use supported amines to adsorb large volumes of CO2. The amines are also selective for CO2. Even when the carbon dioxide is fairly dilute, as in air, these materials are able to withdraw the carbon dioxide from the atmosphere. Thus, the proposed work here focuses on fundamental characterization of connections between CO2 and the specialized adsorbents, targeted towards conventional CCUS.
The purpose of the proposed work is to provide a comprehensive study of specialized solid amine adsorbents in cycles of carbon dioxide adsorption and desorption relevant to CO2 capture from industrial emissions like power plant flue gas and ambient air. The work will bring together traditional adsorption/desorption studies with structural characterization techniques applied to these materials, coupled with computational studies. A particularly innovative aspect will be the application of three different in-situ spectroscopic techniques, infrared, Raman, and nuclear magnetic resonance spectroscopy to probe the structure of the CO2 as it adsorbs to the surface of the specialized amine adsorbent.
A cost-effective technology that could capture carbon dioxide (CO2) from ambient air could minimize the problems associated with transporting large volumes of CO2 from point source emitters (e.g. coal-fired power plants) to sites suitable for geological sequestration. Unlike conventional Carbon Capture Utilization and Storage (CCUS) from large power plant exhaust gases, which can at best slow the rate of increase of the atmospheric CO2 concentration, direct air capture, if widely adopted, can reduce the atmospheric CO2 level. This technology can impact distributed emissions sources (e.g. vehicles) that are currently beyond the reach of carbon capture technologies. The fundamental scientific investigations will provide new insights that will impact a wide array of CO2 adsorption technologies, including post-combustion CO2 capture, the direct extraction of CO2 from ambient air, purification of natural gas streams, and adsorption of CO2 on similar nitrogen-bearing materials for catalysis.
The collaborative project engages scientists from two disciplines, (i) chemical and biomolecular engineering and (ii) chemistry and biochemistry, with student exchanges and collaboration fostering communication across the boundaries of science and engineering.
The project also has significant potential to impact groups that are historically under-represented in science and engineering. PIs will actively recruit under-represented students to take part in this research, engaging Georgia Tech programs such as the Summer Undergraduate Research in Engineering (SURE) program. Additionally, the Institute for School Partnership (ISP) at Washington University will engage secondary school teachers and teach them about CCUS.
