Unravelling moisture-induced CO<sub>2</sub> chemisorption mechanisms in amine-modified sorbents at the molecular scale

Sardo, Mariana; Afonso, Rui; Juźków, Joanna; Pacheco, Marlene; Bordonhos, Marta; Pinto, Moisés L.; Gomes, José R. B.; Mafra, Luís

doi:10.1039/d0ta09808f

Cited by 31 publications

(46 citation statements)

References 63 publications

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“…It has also been proposed that water directly influences the CO 2 transport mechanisms by facilitating deprotonation of the zwitterion intermediate to carbamate species (eqn (3)). 41,47–49 It is also possible that water influences CO 2 transport by other unknown mechanisms.…”

Section: Resultsmentioning

confidence: 99%

Operando observation of CO₂ transport intermediates in polyvinylamine facilitated transport membranes, and the role of water in the formation of intermediates, using transmission FTIR spectroscopy

Pate

O’Brien

2022

J. Mater. Chem. A

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Section: Resultsmentioning

confidence: 99%

Operando observation of CO₂ transport intermediates in polyvinylamine facilitated transport membranes, and the role of water in the formation of intermediates, using transmission FTIR spectroscopy

Pate

O’Brien

2022

J. Mater. Chem. A

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“…The combination of quantitative CSA analysis with Multi-CP and T 1 longitudinal relaxation measurements reveals for the first time the nature of three distinct physisorbed CO 2 environments (D, E, F) in calcined SBA-15 and APTES@ SBA-15 silica, impossible to distinguish resorting to 13 C chemical shift analysis, the most ubiquitous NMR parameter. This methodology has also been used for full quantification of six forms of CO 2 (A−F) detected in these porous materials, that is, the three different forms of chemisorbed CO 2 (A, B, C) encountered in our previous works, 9,11,12,41 plus the three physisorbed CO 2 species mentioned earlier. The relative proportions of the physisorbed CO 2 species are strongly related with the presence of chemisorbed CO 2 species in APTES@SBA-15.…”

Section: Discussionmentioning

confidence: 99%

“Hidden” CO₂ in Amine-Modified Porous Silicas Enables Full Quantitative NMR Identification of Physi- and Chemisorbed CO₂ Species

et al. 2021

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Although spectroscopic investigation of surface chemisorbed CO 2 species has been the focus of most studies, identifying different domains of weakly interacting (physisorbed) CO 2 molecules in confined spaces is less trivial as they are often indistinguishable resorting to (isotropic) NMR chemical shift or vibrational band analyses. Herein, we undertake for the first time a thorough solid-state NMR analysis of CO 2 species physisorbed prior to and after amine-functionalization of silica surfaces; combining 13 C NMR chemical shift anisotropy (CSA) and longitudinal relaxation times ( T 1 ). These methods were used to quantitatively distinguish otherwise overlapping physisorbed CO 2 signals, which contributed to an empirical model of CO 2 speciation for the physi- and chemisorbed fractions. The quantitatively measured T 1 values confirm the presence of CO 2 molecular dynamics on the microsecond, millisecond, and second time scales, strongly supporting the existence of up to three physisorbed CO 2 species with proportions of about 15%, 15%, and 70%, respectively. Our approach takes advantage from using adsorbed 13 C-labeled CO 2 as probe molecules and quantitative cross-polarization magic-angle spinning to study both physi- and chemisorbed CO 2 species, showing that 45% of chemisorbed CO 2 versus 55% of physisorbed CO 2 is formed from the overall confined CO 2 in amine-modified hybrid silicas. A total of six distinct CO 2 environments were identified from which three physisorbed CO 2 were discriminated, coined here as “gas, liquid, and solid-like” CO 2 species. The complex nature of physisorbed CO 2 in the presence and absence of chemisorbed CO 2 species is revealed, shedding light on what fractions of weakly interacting CO 2 are affected upon pore functionalization. This work extends the current knowledge on CO 2 sorption mechanisms providing new clues toward CO 2 sorbent optimization.

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“…compared two different impregnation methods, and the preferred PEI-functionalized hierarchical silica obtained a higher CO 2 adsorption capacity of 4.1 mmol/g than the similar adsorbents under simulated flue gas . In addition, plenty of research has also been conducted on the selection of support types for PEI functionalization, such as polymeric adsorption resins, MOFs, and covalent organic frameworks, apart from the traditional silica, zeolite, metal oxide, and porous carbon . The pore structure of porous support is demonstrated to be the most critical factor for impregnating polyamines .…”

Section: Introductionmentioning

confidence: 99%

Discovering the Interference of Hydrogen Sulfide on Polyethylenimine-Functionalized Porous Resin for Biogas Upgrading via CO₂ Adsorption

Meng

Han

et al. 2021

ACS Sustainable Chem. Eng.

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Because of the considerable CO2 adsorption capacity, selectivity, and stability, amine-functionalized materials have been recently investigated as promising adsorbents for biogas upgrading to biomethane, which provides the preferred gaseous bioenergy resource. Nevertheless, the typical impurity in biogas, H2S, has a potential influence on biogas upgrading, as another acid component to react with amines besides CO2. After all, even the trace H2S after biogas desulfurization might have an accumulative effect, based on previous experience in studying other acid impurities. Herein, we explored the interference of H2S (5–5000 ppm) on the prepared polyethylenimine-functionalized porous resin (PEI/HP20), which has exhibited excellent performance for biogas upgrading. The distinct of adsorption capacity, kinetic behavior, and regeneration performance between the two reactive components (CO2 and H2S) in biogas was systemically investigated. It was found that, in contrast with CO2, the adsorbed H2S on PEI/HP20 was not comparable through slow single-stage kinetic behavior and had limited impact, especially in consideration of the practical biogas upgrading within finite time. Besides, the reversible binding of H2S, proved by the regeneration performance and chemical characterization, was also favorable and pivotal for the PEI/HP20. In addition, the stable operation (capacity loss of 1%) by continuous adsorption–regeneration cycles under H2S-containing simulated biogas have finally demonstrated the ignorable interference of H2S on PEI/HP20, manifesting its strong adaptability in biogas upgrading.

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Unravelling moisture-induced CO₂ chemisorption mechanisms in amine-modified sorbents at the molecular scale

Abstract: Solid-state NMR and molecular modeling provide structural insights on the influence of water upon CO2 chemisorption on primary and tertiary amine-grafted mesoporous silica sorbent materials.

Cited by 31 publications

References 63 publications

Operando observation of CO₂ transport intermediates in polyvinylamine facilitated transport membranes, and the role of water in the formation of intermediates, using transmission FTIR spectroscopy

Operando observation of CO₂ transport intermediates in polyvinylamine facilitated transport membranes, and the role of water in the formation of intermediates, using transmission FTIR spectroscopy

“Hidden” CO₂ in Amine-Modified Porous Silicas Enables Full Quantitative NMR Identification of Physi- and Chemisorbed CO₂ Species

Discovering the Interference of Hydrogen Sulfide on Polyethylenimine-Functionalized Porous Resin for Biogas Upgrading via CO₂ Adsorption

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Unravelling moisture-induced CO2 chemisorption mechanisms in amine-modified sorbents at the molecular scale

Abstract: Solid-state NMR and molecular modeling provide structural insights on the influence of water upon CO2 chemisorption on primary and tertiary amine-grafted mesoporous silica sorbent materials.

Cited by 31 publications

References 63 publications

Operando observation of CO2 transport intermediates in polyvinylamine facilitated transport membranes, and the role of water in the formation of intermediates, using transmission FTIR spectroscopy

Operando observation of CO2 transport intermediates in polyvinylamine facilitated transport membranes, and the role of water in the formation of intermediates, using transmission FTIR spectroscopy

“Hidden” CO2 in Amine-Modified Porous Silicas Enables Full Quantitative NMR Identification of Physi- and Chemisorbed CO2 Species

Discovering the Interference of Hydrogen Sulfide on Polyethylenimine-Functionalized Porous Resin for Biogas Upgrading via CO2 Adsorption

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Unravelling moisture-induced CO₂ chemisorption mechanisms in amine-modified sorbents at the molecular scale

Operando observation of CO₂ transport intermediates in polyvinylamine facilitated transport membranes, and the role of water in the formation of intermediates, using transmission FTIR spectroscopy

Operando observation of CO₂ transport intermediates in polyvinylamine facilitated transport membranes, and the role of water in the formation of intermediates, using transmission FTIR spectroscopy

“Hidden” CO₂ in Amine-Modified Porous Silicas Enables Full Quantitative NMR Identification of Physi- and Chemisorbed CO₂ Species

Discovering the Interference of Hydrogen Sulfide on Polyethylenimine-Functionalized Porous Resin for Biogas Upgrading via CO₂ Adsorption