Moisture-swing sorption for carbon dioxide capture from ambient air: a thermodynamic analysis

Wang, Tao; Lackner, Klaus S.; Wright, Allen

doi:10.1039/c2cp43124f

Cited by 126 publications

(138 citation statements)

References 43 publications

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“…For DAC, sorbents based on strong bases, such as Ca(OH) 2 , NaOH, and combinations thereof, have been proposed, but their regeneration at high temperatures is energy intensive. Another possibility is the use of quaternary ammonium‐functionalized anionic exchange resins, which are regenerated through moisture swing . Recently, adsorbents based on modified metal–organic frameworks (MOFs) and porous polymer networks have also been proposed but remain costly .…”

Section: Resultssupporting

confidence: 84%

Oxidation‐Resistant, Cost‐Effective Epoxide‐Modified Polyamine Adsorbents for CO₂ Capture from Various Sources Including Air

et al. 2019

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CO2 adsorbents based on the reaction of pentaethylenehexamine (PEHA) or tetraethylenepentamine (TEPA) with propylene oxide (PO) were easily prepared in “one pot” by impregnation on a silica support in water. The starting materials were readily available and inexpensive, facilitating the production of the adsorbents on a large scale. The prepared polyamine/epoxide adsorbents were efficient in capturing CO2 and could be regenerated under mild conditions (50–85 °C). They displayed a much‐improved stability compared with their unmodified amine counterparts, especially under oxidative conditions. Leaching of the active organic amine became minimal or nonexistent after treatment with the epoxide. The adsorption as well as desorption kinetics were also greatly improved. The polyamine/epoxide adsorbents were able to capture CO2 from various sources including ambient air and indoor air with CO2 concentrations of only 400–1000 ppm. The presence of water, far from being detrimental, increased the adsorption capacity. Their use for indoor air quality purposes was explored.

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Section: Resultssupporting

confidence: 84%

Oxidation‐Resistant, Cost‐Effective Epoxide‐Modified Polyamine Adsorbents for CO₂ Capture from Various Sources Including Air

et al. 2019

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“…Entropy change ΔS°can be assigned a unified value for reactions 2 or 3 involving different absorbents, because ΔS°o f absorption process is determined by the entropy loss of the CO 2 molecule during the transformation from a gas to a liquid phase, and most liquid CO 2 absorbents have very similar values of ΔS°at a standard condition. 6,29 According to the Campbell's Rule, 30 …”

Section: ·°°°-mentioning

confidence: 99%

Sigmoid Correlations for Gas Solubility and Enthalpy Change of Chemical Absorption of CO₂

Huang

Dai

2015

Ind. Eng. Chem. Res.

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Knowledge of the relationship between gas solubility and enthalpy change of chemical absorption of CO 2 is very important for exploring energy-efficient absorbents for CO 2 capture. To this end, equations that can directly correlate gas solubility with absorption enthalpy were derived through combining the van't Hoff equation with the reaction equilibrium thermodynamic model (RETM). Two typical reaction mechanisms for chemical absorption of CO 2 (1:1 and 1:2) were considered for RETM. The variations of gas solubility with enthalpy change were found to be distinctively sigmoid functions, regardless of the investigated temperature and pressure or assumed reaction forms between CO 2 and the absorbent molecule. Theoretically calculated variation curves of gas solubility vs enthalpy change agreed well with experimental results reported in literature. On the basis of the trade-off relationship between gas solubility and enthalpy change, criterions for evaluating energyefficient chemical absorbents for CO 2 capture were proposed. ■ INTRODUCTIONAs the concentration of atmospheric CO 2 continuously increases, the resulting global warming is attracting widespread attention across academic and industrial communities because of its potentially destructive impact on the environment and ecosystems. CO 2 is mainly emitted in flue gases, which results from the combustion of fossil fuels. 1 A widely used strategy to eliminate CO 2 from industrial gas streams is reversible absorption in liquids. 2 For the purpose of capturing CO 2 from flue gases, chemical absorption is preferred over physical absorption, as the concentration of CO 2 in flue gas is low (10− 15 v/v %). 3 However, the chemical absorption method typically consumes high amounts of energy during the desorption process. 4 Gas solubility and absorption enthalpy are two vital thermodynamic properties for evaluating the performance of chemical absorbents for CO 2 capture. The former indicates how much gas an absorbent can accommodate, and the latter reflects the strength of interaction between the gas and absorbent.For chemical absorbents designated for CO 2 capture, those with high absorption capacity and low enthalpy change are particularly attractive. 5,6 High CO 2 loading is required to reduce the volume of circulation of the absorbents, and low enthalpy change is meaningful for reducing the energy consumed during desorption. However, there is a contradictory relationship between gas solubility and absorption enthalpy since a low enthalpy change in an absorbent is generally accompanied by a low absorption capacity. 7,8 Therefore, finding a proper balance between gas solubility and absorption enthalpy is very important in selecting energy-efficient chemical absorbents for CO 2 capture.Despite the significance of gas solubility and absorption enthalpy, they have usually been treated separately in previous research. Notably, Deshmukh et al. 9 proposed a thermodynamic model based on the extended Debye−Huckel theory of electrolyte solutions for the solubility of CO 2 in alk...

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“…The kinetics of CO 2 adsorption can be generally characterized by monitoring the change of sample weight or CO 2 concentration with time. In this study, as significant water exchange occurs between adsorbents and the atmosphere, the CO 2 adsorption cannot be easily determined by measuring weight change. Therefore, the CO 2 concentration is continuously sampled for a kinetics analysis.…”

Section: Experimental Principles and Model Developmentmentioning

confidence: 99%

Characterization of kinetic limitations to atmospheric CO₂ capture by solid sorbent

et al. 2015

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Scrubbing CO2 directly from the ambient air (air capture) by sorbent is an emerging technology to address climate change due to anthropic emission of greenhouse gases. A good understanding of thermodynamics and reaction kinetics under ultra‐low CO2 concentration and variable humidity is fundamental to the design of economic air capture. In this study, the adsorption kinetics of a novel moisture swing process for air capture is characterized. The variation of humidity alters not only the adsorption equilibrium but also the adsorption kinetics, due to a water involved chemical reaction. A heterogeneously structured sorbent sheet with strong based ion exchange resin inside as active constituent is employed to capture the atmospheric CO2 under different humidity. Traditional shrinking core model (SCM) is modified to reveal the mass transfer resistance inside of the sorbent for CO2 adsorption under ultra‐low CO2 concentration. The modified SCM reveals that, at most cases, the adsorption kinetics is controlled by diffusion inside of the sorbent particle. A transition from physical diffusion controlled kinetics to chemical reaction controlled kinetics is observed as humidity increases. Further kinetic analysis suggests that, among the optimization technologies such as seeking functional group with faster chemical reaction or fabricating thinner support layer, preparing sorbent particle with smaller size or higher porosity should have much more potential on the enhancement of air capture kinetics. © 2015 Society of Chemical Industry and John Wiley & Sons, Ltd

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Moisture-swing sorption for carbon dioxide capture from ambient air: a thermodynamic analysis

Cited by 126 publications

References 43 publications

Oxidation‐Resistant, Cost‐Effective Epoxide‐Modified Polyamine Adsorbents for CO₂ Capture from Various Sources Including Air

Oxidation‐Resistant, Cost‐Effective Epoxide‐Modified Polyamine Adsorbents for CO₂ Capture from Various Sources Including Air

Sigmoid Correlations for Gas Solubility and Enthalpy Change of Chemical Absorption of CO₂

Characterization of kinetic limitations to atmospheric CO₂ capture by solid sorbent

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Moisture-swing sorption for carbon dioxide capture from ambient air: a thermodynamic analysis

Cited by 126 publications

References 43 publications

Oxidation‐Resistant, Cost‐Effective Epoxide‐Modified Polyamine Adsorbents for CO2 Capture from Various Sources Including Air

Oxidation‐Resistant, Cost‐Effective Epoxide‐Modified Polyamine Adsorbents for CO2 Capture from Various Sources Including Air

Sigmoid Correlations for Gas Solubility and Enthalpy Change of Chemical Absorption of CO2

Characterization of kinetic limitations to atmospheric CO2 capture by solid sorbent

Contact Info

Product

Resources

About

Oxidation‐Resistant, Cost‐Effective Epoxide‐Modified Polyamine Adsorbents for CO₂ Capture from Various Sources Including Air

Oxidation‐Resistant, Cost‐Effective Epoxide‐Modified Polyamine Adsorbents for CO₂ Capture from Various Sources Including Air

Sigmoid Correlations for Gas Solubility and Enthalpy Change of Chemical Absorption of CO₂

Characterization of kinetic limitations to atmospheric CO₂ capture by solid sorbent