Support Pore Structure and Composition Strongly Influence the Direct Air Capture of CO<sub>2</sub> on Supported Amines

Rim, Guanhe; Priyadarshini, Pranjali; Song, MinGyu; Wang, Yuxiang; Bai, Andrew; Park, Jongwoo; Lively, Ryan P.; Jones, Christopher W.

doi:10.1021/jacs.2c12707

Cited by 50 publications

(27 citation statements)

References 108 publications

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“…It is evident from Figure b that the adsorption temperature does not significantly impact the desorption profiles, which contrasts with the results obtained for TEPA-incorporated MIL-101(Cr) samples in our earlier study where the desorption peak shifted to lower temperatures with the decrease in adsorption temperature, indicating that the temperature of adsorption is critical in determining the interaction of CO 2 to the amines when MIL-101(Cr) was used as a support . The differences in the results using different supports (γ-Al 2 O 3 in this study and MIL-101(Cr)) as well as the difference in CO 2 uptake trends with different temperatures and loadings indicate that the choice of the support is crucial in determining the performance of the sorbent at a particular condition …”

Section: Resultscontrasting

confidence: 99%

“…The promising performance of PEI- and TEPA-impregnated powder sorbents (γ-Al 2 O 3 in this study, and MIL-101(Cr) in previous studies , ) at ambient and sub-ambient conditions, under both dry and humid conditions, provides preliminary data that can be used to further optimize these sorbents. Powder sorbents are ideal for lab-scale applications but not for industrial applications when pressure drop is a key performance metric, as in DAC.…”

Section: Future Directions and Study Limitationsmentioning

confidence: 63%

“…An alternate hypothesis is that the longer PEI chains are more sensitive to water disrupting amine–amine hydrogen-bonding networks, and water more effectively lubricates the chains of PEI than TEPA. For the 20 wt % TEPA sample, it is likely that the formation of carbamate ions is enhanced at −20 °C in the presence of moisture . At higher loadings, diffusion limitations due to high pore filling (∼70%) coupled with frozen/arrested chains may be responsible for the lowered CO 2 capacities.…”

Section: Resultsmentioning

confidence: 99%

“…Mesoporous γ-Al 2 O 3 (particle size ∼6.9 μm, pore size (mode) ∼16.1 nm) was sourced commercially from Global Thermostat, LLC. Branched poly(ethyleneimine) (PEI-800, M w ∼800, M n ∼600 Sigma-Aldrich), tetraethylenepentamine (TEPA, Sigma-Aldrich), spermine (>97%, Sigma-Aldrich), and spermidine (>99%, Sigma-Aldrich) were incorporated into the pores of alumina by physical impregnation, as described elsewhere .…”

Section: Methodsmentioning

confidence: 99%

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Direct Air Capture of CO₂ Using Amine/Alumina Sorbents at Cold Temperature

et al. 2023

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Rising CO2 emissions are responsible for increasing global temperatures causing climate change. Significant efforts are underway to develop amine-based sorbents to directly capture CO2 from air (called direct air capture (DAC)) to combat the effects of climate change. However, the sorbents’ performances have usually been evaluated at ambient temperatures (25 °C) or higher, most often under dry conditions. A significant portion of the natural environment where DAC plants can be deployed experiences temperatures below 25 °C, and ambient air always contains some humidity. In this study, we assess the CO2 adsorption behavior of amine (poly(ethyleneimine) (PEI) and tetraethylenepentamine (TEPA)) impregnated into porous alumina at ambient (25 °C) and cold temperatures (−20 °C) under dry and humid conditions. CO2 adsorption capacities at 25 °C and 400 ppm CO2 are highest for 40 wt% TEPA-incorporated γ-Al2O3 samples (1.8 mmol CO2/g sorbent), while 40 wt % PEI-impregnated γ-Al2O3 samples exhibit moderate uptakes (0.9 mmol g–1). CO2 capacities for both PEI- and TEPA-incorporated γ-Al2O3 samples decrease with decreasing amine content and temperatures. The 40 and 20 wt % TEPA sorbents show the best performance at −20 °C under dry conditions (1.6 and 1.1 mmol g–1, respectively). Both the TEPA samples also exhibit stable and high working capacities (0.9 and 1.2 mmol g–1) across 10 cycles of adsorption–desorption (adsorption at −20 °C and desorption conducted at 60 °C). Introducing moisture (70% RH at −20 and 25 °C) improves the CO2 capacity of the amine-impregnated sorbents at both temperatures. The 40 wt% PEI, 40 wt % TEPA, and 20 wt% TEPA samples show good CO2 uptakes at both temperatures. The results presented here indicate that γ-Al2O3 impregnated with PEI and TEPA are potential materials for DAC at ambient and cold conditions, with further opportunities to optimize these materials for the scalable deployment of DAC plants at different environmental conditions.

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Section: Resultscontrasting

confidence: 99%

Section: Future Directions and Study Limitationsmentioning

confidence: 63%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Direct Air Capture of CO₂ Using Amine/Alumina Sorbents at Cold Temperature

et al. 2023

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“…Supported amines typically exhibit limited AE, reaching up to ∼0.2 under dry 400 ppm of CO 2 , simulating DAC. , This value is far from the theoretical maxima (0.5). Rationalizing these behaviors requires knowledge of the local structure of the polyamines within the support pores as well as insight into amine mobility, including center of mass diffusion, local chain mobility, and bond dynamics.…”

Section: Introductionmentioning

confidence: 99%

Distribution and Mobility of Amines Confined in Porous Silica Supports Assessed via Neutron Scattering, NMR, and MD Simulations: Impacts on CO₂ Sorption Kinetics and Capacities

Moon,

Carrillo,

Jones

2023

Acc. Chem. Res.

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Conspectus Solid-supported amines are a promising class of CO2 sorbents capable of selectively capturing CO2 from diverse sources. The chemical interactions between the amine groups and CO2 give rise to the formation of strong CO2 adducts, such as alkylammonium carbamates, carbamic acids, and bicarbonates, which enable CO2 capture even at low driving force, such as with ultradilute CO2 streams. Among various solid-supported amine sorbents, oligomeric amines infused into oxide solid supports (noncovalently supported) are widely studied due to their ease of synthesis and low cost. This method allows for the construction of amine-rich sorbents while minimizing problems, such as leaching or evaporation, that occur with supported molecular amines. Researchers have pursued improved sorbents by tuning the physical and chemical properties of solid supports and amine phases. In terms of CO2 uptake, the amine efficiency, or the moles of sorbed CO2 per mole of amine sites, and uptake rate (CO2 capture per unit time) are the most critical factors determining the effectiveness of the material. While structure–property relationships have been developed for different porous oxide supports, the interaction(s) of the amine phase with the solid support, the structure and distribution of the organic phase within the pores, and the mobility of the amine phase within the pores are not well understood. These factors are important, because the kinetics of CO2 sorption, particularly when using the prototypical amine oligomer branched poly(ethylenimine) (PEI), follow an unconventional trend, with rapid initial uptake followed by a very slow, asymptotic approach to equilibrium. This suggests that the uptake of CO2 within such solid-supported amines is mass transfer-limited. Therefore, improving sorption performance can be facilitated by better understanding the amine structure and distribution within the pores. In this context, model solid-supported amine sorbents were constructed from a highly ordered, mesoporous silica SBA-15 support, and an array of techniques was used to probe the soft matter domains within these hybrid materials. The choice of SBA-15 as the model support was based on its ordered arrangement of mesopores with tunable physical and chemical properties, including pore size, particle lengths, and surface chemistries. Branched PEIthe most common amine phase used in solid CO2 sorbentsand its linear, low molecular weight analogue, tetraethylenepentamine (TEPA), were deployed as the amine phases. Neutron scattering (NS), including small angle neutron scattering (SANS) and quasielastic neutron scattering (QENS), alongside solid-state NMR (ssNMR) and molecular dynamics (MD) simulations, was used to elucidate the structure and mobility of the amine phases within the pores of the support. Together, these tools, which have previously not been applied to such materials, provided new information regarding how the amine phases filled the support pores as the loading increased and the mobility of those amine phases. Varying pore ...

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Translocation and Confinement of Tetraamines in Adaptable Microporous Cavities

Rubio‐Gaspar,

Misturini,

Millan

et al. 2024

Angewandte Chemie

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Metal‐Organic Frameworks can be grafted with amines by coordination to metal vacancies to create amine‐appended solid adsorbents, which are being considered as an alternative to using aqueous amine solutions for CO2 capture. In this study, we propose an alternative mechanism that does not rely on the use of neutral metal vacancies as binding sites but is enabled by the structural adaptability of heterobimetallic Ti2Ca2 clusters. The combination of hard (Ti+4) and soft (Ca2+) metal centers in the inorganic nodes of the framework enables MUV‐10 to adapt its pore windows to the presence of triethylenetetramine molecules. This dynamic cluster response facilitates the translocation and binding of tetraamine inside the microporous cavities to enable the formation of bis‐coordinate adducts that are stable in water. The extension of this grafting concept from MUV‐10 to larger cavities not restrictive to CO2 diffusion will complement other strategies available for the design of molecular sorbents for decarbonization applications.

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Support Pore Structure and Composition Strongly Influence the Direct Air Capture of CO₂ on Supported Amines

Cited by 50 publications

References 108 publications

Direct Air Capture of CO₂ Using Amine/Alumina Sorbents at Cold Temperature

Direct Air Capture of CO₂ Using Amine/Alumina Sorbents at Cold Temperature

Distribution and Mobility of Amines Confined in Porous Silica Supports Assessed via Neutron Scattering, NMR, and MD Simulations: Impacts on CO₂ Sorption Kinetics and Capacities

Translocation and Confinement of Tetraamines in Adaptable Microporous Cavities

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Support Pore Structure and Composition Strongly Influence the Direct Air Capture of CO2 on Supported Amines

Cited by 50 publications

References 108 publications

Direct Air Capture of CO2 Using Amine/Alumina Sorbents at Cold Temperature

Direct Air Capture of CO2 Using Amine/Alumina Sorbents at Cold Temperature

Distribution and Mobility of Amines Confined in Porous Silica Supports Assessed via Neutron Scattering, NMR, and MD Simulations: Impacts on CO2 Sorption Kinetics and Capacities

Translocation and Confinement of Tetraamines in Adaptable Microporous Cavities

Contact Info

Product

Resources

About

Support Pore Structure and Composition Strongly Influence the Direct Air Capture of CO₂ on Supported Amines

Direct Air Capture of CO₂ Using Amine/Alumina Sorbents at Cold Temperature

Direct Air Capture of CO₂ Using Amine/Alumina Sorbents at Cold Temperature

Distribution and Mobility of Amines Confined in Porous Silica Supports Assessed via Neutron Scattering, NMR, and MD Simulations: Impacts on CO₂ Sorption Kinetics and Capacities