Evaluation of amine-based solid adsorbents for direct air capture: a critical review

Panda, Debashis; Kulkarni, Vaishnavi; Singh, Sanjay Kumar

doi:10.1039/d2re00211f

Cited by 26 publications

(9 citation statements)

References 197 publications

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“…Porous silicas constitute a family of robust adsorbents, yet unmodified silica exhibits noncompetitive CO 2 capacity and selectivity. To this end, a number of works on amine incorporation on mesoporous silicas by both impregnation and grafting techniques have been reported for CO 2 capture. ,, In a recent review, Panda et al critically discussed the applicability of amine-modified solid adsorbents, including silica-based ones, for direct air capture (DAC). Despite the well-defined porosity characteristics and amine incorporation and adsorption behavior in mesoporous adsorbents, supports exhibiting multiporosity are attractive as multifunctional systems to efficiently tune diffusion and adsorption, as well as optimize capacity, selectivity, and regeneration.…”

Section: Introductionmentioning

confidence: 99%

Aminosilane-Modified Ordered Hierarchical Nanostructured Silica for Highly-Selective Carbon Dioxide Capture at Low Pressure

Reddy

Varghese

Ogungbenro

et al. 2023

ACS Appl. Eng. Mater.

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Ordered hierarchical nanostructured silica (OHNS) adsorbents were prepared, and their surface was controllably modified by aminosilanization using two different aminosilanes, one bearing one primary amine unit per molecule (4-aminobutyltriethoxysilane, ABTS) and the other bearing both a primary and a secondary amine (N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, AAMS). Following physicochemical, structural, morphological, and porosity characterization, the CO2 adsorption performance was evaluated at low pressures (up to 100 mbar) and at different temperatures (25, 45, and 60 °C), including determination of CO2 adsorption–desorption, kinetics, CO2/N2 selectivity, regeneration/cycling, heat of adsorption, and CO2 adsorption under humid conditions. The unique hierarchical silica framework together with the aminosilanization scheme applied resulted in enhanced kinetics and CO2 uptake, the latter being increased with temperature, thus revealing a dominant chemisorption mechanism, which was further evidenced by the increase in the enthalpy of adsorption of the modified materials compared to the pristine OHNS. Among the tested adsorbents, at 100 mbar and 25 °C, the OHNS modified by AAMS yielded the highest CO2 uptake under dry (1.3 mmol/g) and wet (1.9 mmol/g) conditions. Notably, at very low pressure (1 mbar), the CO2 capacity of OHNS-AAMS reached >40% of the material’s total uptake at 1 bar. Compared to the unmodified OHNS, the CO2 capacity of the OHNS-AAMS and OHNS-ABTS increased by approximately 21- and 16-fold, respectively, at 1 mbar and 25 °C. At even lower pressure (0.4 mbar), a capacity of 0.55 mmol/g was evidenced for OHNS-AAMS in dry CO2. A very high CO2/N2 selectivity of the AAMS-modified analogue at low pressure was also obtained, i.e., 13,854 at 50 mbar, confirming the significant increase in CO2-philicity via aminosilanization with aminosilanes bearing combined primary and secondary amine groups. Furthermore, the water affinity of the aminosilane-modified OHNS adsorbents was found to decrease, which is beneficial for capture from humid mixtures. Cyclic stability was confirmed by performing 10 thermal pressure swing adsorption (TPSA) cycles up to 100 mbar. The hierarchical nanostructured silica-based framework and the functionalization scheme presented here render these robust systems promising for selective CO2 capture at low pressures in industrial applications and direct air capture.

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Section: Introductionmentioning

confidence: 99%

Aminosilane-Modified Ordered Hierarchical Nanostructured Silica for Highly-Selective Carbon Dioxide Capture at Low Pressure

Reddy

Varghese

Ogungbenro

et al. 2023

ACS Appl. Eng. Mater.

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“…The ideal CO 2 sorbent should exhibit fast kinetics and high selectivity toward CO 2 from the CO 2 -lean atmosphere (∼420 ppm CO 2 ). Hence, CO 2 should bind strongly to the adsorbent but not so effectively as to require regeneration at temperatures or conditions that will be cost-prohibitive. , Amine-based porous adsorbents have shown potential owing to their high CO 2 uptake capacities and lower temperature requirements for regeneration, which translates to lower energy and hence lower capital requirements. ,,− However, most studies have primarily focused on studying these materials at 25 °C and higher. − Additionally, relatively few studies take into account the effect of water vapor in the atmosphere while evaluating the performance of the sorbents. Temperatures vary significantly across the globe (from −30 to 30 °C), and ∼70% of the world has an average temperature lower than 25 °C. , Studies focusing on cooler conditions (<25 °C) , are few and far between, which precludes informed operation in a large geographical area.…”

Section: Introductionmentioning

confidence: 99%

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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“…As discussed above, higher amine loadings for low concentrations of CO 2 can result in higher CO 2 capture capacity. Therefore, higher CO 2 capture capacity with impregnated amines is due to the fact that the amines do not require specific binding sites [41].…”

Section: Effect Of the Preparation Methodsmentioning

confidence: 99%

Data‐Driven Analysis of Amine‐Based Sorbents for CO₂ Removal from the Atmosphere

Bahmanpour,

Tegeler,

Colbert

et al. 2023

Chem Eng & Technol

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Available data on amine‐based sorbents used for the direct air capture (DAC) process were gathered and analyzed to identify the correlations between various aspects of these sorbents and the operating conditions they are used in. It is demonstrated that a moderately high temperature (∼ 50 °C) can help with higher CO2 capture capacity. The effect of sorbent preparation method on its activity and stability was studied. Also, the influence of amine groups and support choice on amine efficiency and CO2 capture capacity was discussed. The DAC process conditions proved to play a major role in determining the optimal sorbent. An outlook for characteristics to be sought for in future DAC sorbents for CO2 removal is proposed.

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Evaluation of amine-based solid adsorbents for direct air capture: a critical review

Abstract: Direct Air Capture (DAC) emerges as a new technology that can contribute to “negative carbon emission.” Recent progress in surface chemistry and material synthesis has allowed a new generation of...

Cited by 26 publications

References 197 publications

Aminosilane-Modified Ordered Hierarchical Nanostructured Silica for Highly-Selective Carbon Dioxide Capture at Low Pressure

Aminosilane-Modified Ordered Hierarchical Nanostructured Silica for Highly-Selective Carbon Dioxide Capture at Low Pressure

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

Data‐Driven Analysis of Amine‐Based Sorbents for CO₂ Removal from the Atmosphere

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Evaluation of amine-based solid adsorbents for direct air capture: a critical review

Abstract: Direct Air Capture (DAC) emerges as a new technology that can contribute to “negative carbon emission.” Recent progress in surface chemistry and material synthesis has allowed a new generation of...

Cited by 26 publications

References 197 publications

Aminosilane-Modified Ordered Hierarchical Nanostructured Silica for Highly-Selective Carbon Dioxide Capture at Low Pressure

Aminosilane-Modified Ordered Hierarchical Nanostructured Silica for Highly-Selective Carbon Dioxide Capture at Low Pressure

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

Data‐Driven Analysis of Amine‐Based Sorbents for CO2 Removal from the Atmosphere

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

Data‐Driven Analysis of Amine‐Based Sorbents for CO₂ Removal from the Atmosphere