Overcoming the Entropy Penalty of Direct Air Capture for Efficient Gigatonne Removal of Carbon Dioxide

Abstract

Atmospheric carbon poses an existential threat to civilization via global climate change. Hundreds of gigatonnes of carbon dioxide must be removed from earth's atmosphere in the next three decades, necessitating a low-cost, energy-efficient process to extract low concentrations of carbon dioxide for conversion to a stable material permanently stored for thousands of years. In this work, the challenge of removing gigatonnes of CO 2 is described via the scale of effort and the thermodynamics of collecting and reducing this diffuse chemical, the accumulation of which imparts a substantial entropy penalty on any atmospheric carbon capture process. The methods of CO 2 reduction combined with upstream direct air capture (DAC) including absorption, membrane separation, and adsorption are compared with biomass torrefaction and permanent burial (BTB). A Monte Carlo model assesses the mass, energy, and economics of the full process of biomass torrefaction from biomass collection and transport to stable carbon burial to determine that 95% of scenarios could remove carbon for less than $200 per CO 2 -tonne-equivalent. Torrefied carbon is further discussed for its long-term stability and availability at the scale required to substantially mitigate the threat of climate change.

Nickel single atom catalyst supported on the gallium nitride monolayer: first principles investigations on the decisive role of support in the electrocatalytic reduction of CO2

“…To locate the most suitable binding site, we considered adsorption of Ni single atoms on different distinct sites on these supports as depicted in Fig. 1(a) and evaluated the binding energies on these sites using eqn (1). The lowest energy congurations of Ni single atoms on different supports and their binding energies are presented in Fig.…”

“…Excessive consumption of fossil fuels has resulted in accumulation of higher concentrations of CO 2 in the atmosphere, posing a serious challenge to sustainable development on earth. 1,2 The global estimates of CO 2 are expected to shoot up to 600 ppm by the end of this century, leading to serious environmental and health issues. Thus, mitigating the concentrations of CO 2 and converting it into useful chemicals has become an important research topic.…”

Biomass composting with gaseous carbon dioxide capture

“…2 Relative to direct air capture technologies, BiCRS technologies require signicantly less energy in the forms of electricity and heat, which enables the potential for signicantly lower costs of CO 2 capture and stabilization. 3 The leading BiCRS technologies include gasication, pyrolysis, combustion, anaerobic digestion, fermentation and biomass burial. 4 Given the urgency of the changing climate, society needs BiCRS solutions that scale quickly with minimal risk.…”

Dual Functional Materials: At the Interface of Catalysis and Separations

“…In this Perspective, we are focused on CO 2 capture and conversion from flue gas because of the high entropy penalty of separating CO 2 from air and significant thermal losses that may occur when DFMs are used during direct air capture (DAC) if the residual heat after reaction is not efficiently utilized. 8 The efficiency of capturing CO 2 as a function of the source concentration is detailed in the Sherwood plot in Figure S1 of the Supporting Information. 9 To accelerate progress in DFM research, we need to ensure that DFMs are studied under the relevant conditions, without the pretense that a better DFM will solve all implementation challenges.…”

“…The key distinction between the two processes is that CO 2 is reactively separated from flue gas in one step instead of separating and reacting CO 2 over two different materials in separate locations. In this Perspective, we are focused on CO 2 capture and conversion from flue gas because of the high entropy penalty of separating CO 2 from air and significant thermal losses that may occur when DFMs are used during direct air capture (DAC) if the residual heat after reaction is not efficiently utilized . The efficiency of capturing CO 2 as a function of the source concentration is detailed in the Sherwood plot in Figure S1 of the Supporting Information …”