Study on MNO3/NO2 (M = Li, Na, and K)/MgO Composites for Intermediate-Temperature CO2 Capture

Gao, Wanlin; Zhou, Tuantuan; Gao, Yanshan; Wang, Qiang; Lin, Weiran

doi:10.1021/acs.energyfuels.8b02749

Cited by 36 publications

(32 citation statements)

References 49 publications

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“…[26] The X-ray photoelectron spectroscopy (XPS) spectrum of fresh NaNO 2 -promoted MgO sample depicted in Figure 1b shows a peak at 403.8 eV, which is attributed to the N 1s core level of NO 2 − . [27] The N 1s peak was shifted from 403.8 eV before calcination to 407.4 eV after calcination, which is ascribed to the conversion of part of NaNO 2 to NaNO 3 [4,28] since the obtained X-ray photoelectron spectrum of the calcined material still showed a peak at 403.8 eV. This result is also in accordance with previously studied nitrite-promoted adsorbents, [9,29] though the NaNO 2 phase was not present in the XRD pattern after calcination.…”

Section: Structure and Surface Composition Of Molten-salt-promoted Mgosupporting

confidence: 88%

“…The latter is due to the lower diffraction intensities derived from the various planes of NaNO 2 and its smaller amount (wt%) present in the sample. [23,28] Scanning electron microscopy (SEM) studies were further conducted on NaNO 2 -promoted MgO after activation, and typical adsorbent agglomerated particles are shown in Figure S1a, Supporting Information. Furthermore, energy-dispersive X-ray spectroscopy (EDS) analysis (N, O, Na, and Mg) indicated that the molten salt was evenly dispersed on the MgO surface (Figure S1b, Supporting Information).…”

Section: Structure and Surface Composition Of Molten-salt-promoted Mgomentioning

confidence: 99%

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Unravelling the Mechanism of Intermediate‐Temperature CO₂ Interaction with Molten‐NaNO₃‐Salt‐Promoted MgO

et al. 2021

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The optimization of MgO‐based adsorbents as advanced CO2‐capture materials is predominantly focused on their molten‐salt modification, for which theoretical and experimental contributions provide great insights for their high CO2‐capture performance. The underlying mechanism of the promotion effect of the molten salt on CO2 capture, however, is a topic of controversy. Herein, advanced experimental characterization techniques, including in situ environmental transmission electron microscopy (eTEM) and CO2 chemisorption by diffuse‐reflectance infrared Fourier transform spectroscopy (DRIFTS), transient 18O‐isotopic exchange, and density functional theory (DFT), are employed to elucidate the mechanism of the CO2 interaction with molten‐salt‐modified MgO in the 250–400 °C range. Herein, eTEM studies using low (2–3 mbar) and high (700 mbar) CO2 pressures illustrate the dynamic evolution of the molten NaNO3 salt promoted and unpromoted MgO carbonation with high magnification (<50 nm). The formation of 18O‐NaNO3 (use of 18O2) and C16O18O following CO2 interaction, verifies the proposed reaction path: conversion of NO3− (NO3− → NO2+ + O2–), adsorption of NO2+ on MgO with significant weakening of CO2 adsorption strength, and formation of [Mg2+… O2−] ion pairs preventing the development of an impermeable MgCO3 shell, which largely increases the rate of bulk MgO carbonation.

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Section: Structure and Surface Composition Of Molten-salt-promoted Mgosupporting

confidence: 88%

Section: Structure and Surface Composition Of Molten-salt-promoted Mgomentioning

confidence: 99%

Unravelling the Mechanism of Intermediate‐Temperature CO₂ Interaction with Molten‐NaNO₃‐Salt‐Promoted MgO

et al. 2021

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“…Fortunately, doping alkali salts into MgO can significantly facilitate the sorption of CO 2 [20]. These alkali salts can be classified into four categories, i.e., single components [23][24][25][26][27], double salts [28][29][30][31], triple salts [32][33][34][35] and multiple salts [36,37]. For K 2 CO 3 -doped sorbents, recent studies indicate that the CO 2 sorption ability was increased to 10.2-11.7 wt% [38,39].…”

Section: Introductionmentioning

confidence: 99%

Structural and kinetic analysis of CO2 sorption on NaNO2-promoted MgO at moderate temperatures

Wang

Zhao

Clough

et al. 2019

Chemical Engineering Journal

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Alkali metal nitrate-/nitrite-promoted MgO sorbents are promising candidates for intermediate-temperature (200-500 °C) CO 2 capture. However, the structure-performance relationship and kinetic characteristics of NaNO 2-promoted MgO remain unclear. Here the effects of physical-chemical properties on the CO 2 sorption performance of NaNO 2-promoted MgO and the sorption kinetics were comprehensively studied to elucidate the detailed role of NaNO 2. Samples were characterized by X-ray diffraction, scanning electron microscopy, N 2 adsorption, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The sorption kinetics were obtained by isothermal thermogravimetry and elucidated using a double exponential model. Compared with pure MgO and NaNO 3-promoted MgO, NaNO 2-modified MgO had a lower initial sorption temperature and a unique bimodal sorption characteristic. Characterizations results revealed that such bimodal sorption

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“…The different promotion effects of these alkali metal nitrates can be associated with their different melting temperatures and the varied CO 2 solubility in these molten salts . It is indicated that the melting points of NaNO 3 , KNO 3 , and LiNO 3 are 307, 334, and 255 °C, respectively. , Compared to these single molten salts, the alkali metal nitrate eutectic mixtures show relatively lower melting points. For instance, the melting points of the binary nitrates of (K–Na)NO 3 and (Li 0.44 K 0.56 )NO 3 are 222 and ∼137 °C. , Theoretically, the binary molten salts should fuse more easily, allowing for facilitated CO 2 dissolution in the molten salts for improved carbonation reactivity.…”

Section: Resultsmentioning

confidence: 99%

“…48 It is indicated that the melting points of NaNO 3 , KNO 3 , and LiNO 3 are 307, 334, and 255 °C, respectively. 39,49 Compared to these single molten salts, the alkali metal nitrate eutectic mixtures show relatively lower melting points. For instance, the melting points of the binary nitrates of (K−Na)NO 3 and (Li 0.44 K 0.56 )NO 3 are 222 and ∼137 °C.…”

Section: Resultsmentioning

confidence: 99%

Alkali Metal Nitrates Promoted MgO Composites with High CO₂ Uptake for Thermochemical Energy Storage

Zhang

Zheng

Guo

et al. 2021

ACS Appl. Energy Mater.

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Thermochemical energy storage (TCES) by means of reversible chemical reactions represents a promising strategy for harnessing renewable energy and recovering industrial waste heat. In this work, alkali metal nitrate promoted MgO composites were synthesized, and the MgO−CO 2 working pair was suggested as an alternative candidate for harvesting intermediatetemperature industrial waste heat. However, it remains unclear how operating parameters would affect the heat storage density, and the long-term cycling stability of the alkali metal nitrate promoted MgO composites under harsh conditions close to practical application scenarios needs to be clarified. The objectives of this work are to expound the effects of operating parameters on TCES performance and to evaluate the long-term cycling stability of the alkali metal nitrate promoted MgO composites. With increasing NaNO 3 content, the heat storage density of NaNO 3 −MgO increases dramatically first and then exhibits no significant change. With rising carbonation temperature, the heat storage density of the 10NaNO 3 −MgO composite increases first and then declines marginally, while it increases with the increasing CO 2 partial pressure. Doping alkali metal nitrate eutectic mixtures adversely affects the heat storage density. 10NaNO 3 −MgO exhibits a high heat storage density of 2291 kJ/kg at 340 °C in 100% CO 2 . The 10NaNO 3 −MgO and 10(K−Na)NO 3 −MgO composites suffer a significant decline in heat storage density within 10 consecutive cycles, while 10(Li−Na)NO 3 −MgO retains good stability with a slight decrease of heat storage density from 1073 to 770 kJ/kg in 50% CO 2 . The desired 10(Li−Na)NO 3 −MgO is suggested as a promising material for TCES application.

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Study on MNO₃/NO₂ (M = Li, Na, and K)/MgO Composites for Intermediate-Temperature CO₂ Capture

Cited by 36 publications

References 49 publications

Unravelling the Mechanism of Intermediate‐Temperature CO₂ Interaction with Molten‐NaNO₃‐Salt‐Promoted MgO

Unravelling the Mechanism of Intermediate‐Temperature CO₂ Interaction with Molten‐NaNO₃‐Salt‐Promoted MgO

Structural and kinetic analysis of CO2 sorption on NaNO2-promoted MgO at moderate temperatures

Alkali Metal Nitrates Promoted MgO Composites with High CO₂ Uptake for Thermochemical Energy Storage

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Study on MNO3/NO2 (M = Li, Na, and K)/MgO Composites for Intermediate-Temperature CO2 Capture

Cited by 36 publications

References 49 publications

Unravelling the Mechanism of Intermediate‐Temperature CO2 Interaction with Molten‐NaNO3‐Salt‐Promoted MgO

Unravelling the Mechanism of Intermediate‐Temperature CO2 Interaction with Molten‐NaNO3‐Salt‐Promoted MgO

Structural and kinetic analysis of CO2 sorption on NaNO2-promoted MgO at moderate temperatures

Alkali Metal Nitrates Promoted MgO Composites with High CO2 Uptake for Thermochemical Energy Storage

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Study on MNO₃/NO₂ (M = Li, Na, and K)/MgO Composites for Intermediate-Temperature CO₂ Capture

Unravelling the Mechanism of Intermediate‐Temperature CO₂ Interaction with Molten‐NaNO₃‐Salt‐Promoted MgO

Unravelling the Mechanism of Intermediate‐Temperature CO₂ Interaction with Molten‐NaNO₃‐Salt‐Promoted MgO

Alkali Metal Nitrates Promoted MgO Composites with High CO₂ Uptake for Thermochemical Energy Storage