The Use of Biogas in MCFCs and SOFCs Technology: Adsorption Processes and Adsorbent Materials for Removal of Noxious Compounds

Turco, Maria Caterina; Ausiello, Angelo; Micoli, Luca

doi:10.1007/978-3-319-03215-3_4

Cited by 2 publications

(2 citation statements)

References 160 publications

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“…Along with the CO 2 /N 2 separation performance, we compared the CO 2 /CH 4 separation performances of M_0mM and M_50mM at 40–50 °C with those of SAPO-34, DDR, SSZ-13, , and Si-CHA zeolite membranes (Figure b). In particular, the CO 2 /CH 4 separation performances were compared at 40–50 °C, which are the representative temperatures of biogas streams. , Under dry conditions, M_50mM showed CO 2 /CH 4 SF superior to that of the high-quality SSZ-13 membrane . Indeed, both eight-membered ring CHA and DDR-type zeolite membranes, which are highly expected to recognize the size difference between the CO 2 and CH 4 molecules, were desirable for performing the separation of CO 2 from the bulkier CH 4 than from the slightly smaller N 2 .…”

Section: Resultsmentioning

confidence: 99%

Healing of Microdefects in SSZ-13 Membranes via Filling with Dye Molecules and Its Effect on Dry and Wet CO₂ Separations

et al. 2018

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It is quite challenging to avoid microdefect formation during hydrothermal growths and/or calcination processes, while manufacturing high-quality zeolite membranes in a reproducible manner. Even less than 1% of defects, which generally provide nonselective pathways, will considerably worsen the intrinsic, high molecular sieving-based separation performance of a continuous zeolite membrane. Herein, we propose a simple and reliable method for blocking defects using water-soluble dye molecules, which were originally used for the visualization of nonzeolitic, defective structures in a zeolite membrane. Because the dye molecules are ∼1 nm in size, they cannot diffuse into the zeolitic pores and selectively access the defects. For the demonstration of dye-based defect healing, we chose a siliceous chabazite type SSZ-13 zeolite membrane (pore size = 0.37 × 0.42 nm 2 ) with some degree of defects and investigated the effect of defect healing on the final CO 2 separation performance. Because the defects were gradually filled by the dye molecules, both CO 2 /N 2 and CO 2 /CH 4 separation performances were concomitantly increased. Intriguingly, the CO 2 permselectivity test with ternary mixtures including H 2 O vapor (the third largest component in the flue and natural/shale/bio gas streams) in the feed diminished CO 2 separation performance. This could be ascribed to inhibited transport of the fast permeating species, here CO 2 , from the adsorbed H 2 O molecules on the dye-treated and water-friendly (relatively hydrophilic) membrane surface. On the contrary, the intact, siliceous (water-repelling or hydrophobic) SSZ-13 membranes showed improved CO 2 permselectivities in the presence of H 2 O vapor, seemingly due to defect blocking by the physisorbed H 2 O molecules.

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Section: Resultsmentioning

confidence: 99%

Healing of Microdefects in SSZ-13 Membranes via Filling with Dye Molecules and Its Effect on Dry and Wet CO₂ Separations

et al. 2018

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“…3–6 vol %) at ca. 40–70 °C. , We found that most studies in the literature were done to investigate CO 2 /N 2 and CO 2 /CH 4 separation performance at ca. 25–30 °C under dry conditions, instead of the more realistic wet conditions at temperatures of ca.…”

Section: Introductionmentioning

confidence: 99%

Chabazite-Type Zeolite Membranes for Effective CO₂ Separation: The Role of Hydrophobicity and Defect Structure

Lee

Hong

Kim

et al. 2019

ACS Appl. Mater. Interfaces

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Chabazite (CHA)-type zeolites are promising for the separation of CO 2 from larger molecules, such as N 2 (relevant to postcombustion carbon capture) and CH 4 (relevant to natural gas/biogas upgrading). In particular, the pore size of CHA zeolites (0.37 × 0.42 nm 2 ) can recognize slight molecular size differences between CO 2 (0.33 nm) and the larger N 2 (0.364 nm) or CH 4 (0.38 nm) molecules, thus allowing separation in favor of CO 2 through CHA membranes. Furthermore, the siliceous constituents in the CHA zeolite can reduce the adsorption capacity toward the smaller H 2 O molecule (0.265 nm) and, thus, the H 2 O permeation rate. This is highly desirable for securing good molecular sieving ability with CO 2 permselectivity in the presence of H 2 O vapor. Indeed, a siliceous CHA film obtained with a nominal Si/Al ratio of 100 (CHA_100) showed high CO 2 /N 2 and CO 2 /CH 4 separation performance, especially in the presence of H 2 O vapor; ∼13.4 CO 2 /N 2 and ∼37 CO 2 /CH 4 separation factors (SFs) at 30 °C. These SFs were higher than the corresponding values (∼5.2 CO 2 /CH 4 SFs and ∼31 CO 2 /CH 4 SFs) under dry conditions; such improvement could be ascribed to defect blocking by physisorbed water molecules. Finally, the contribution of molecular transport through zeolitic and nonzeolitic parts was quantitatively analyzed by combining information extracted from image processing of fluorescence confocal optical microscopy images with a one-dimensional permeation model. It appears that ∼19 and ∼20% of the total CO 2 permeance for CHA_100 were reduced due to transport inhibition by the physisorbed water molecules on the membrane surface and defect, respectively.

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The Use of Biogas in MCFCs and SOFCs Technology: Adsorption Processes and Adsorbent Materials for Removal of Noxious Compounds

Cited by 2 publications

References 160 publications

Healing of Microdefects in SSZ-13 Membranes via Filling with Dye Molecules and Its Effect on Dry and Wet CO₂ Separations

Healing of Microdefects in SSZ-13 Membranes via Filling with Dye Molecules and Its Effect on Dry and Wet CO₂ Separations

Chabazite-Type Zeolite Membranes for Effective CO₂ Separation: The Role of Hydrophobicity and Defect Structure

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The Use of Biogas in MCFCs and SOFCs Technology: Adsorption Processes and Adsorbent Materials for Removal of Noxious Compounds

Cited by 2 publications

References 160 publications

Healing of Microdefects in SSZ-13 Membranes via Filling with Dye Molecules and Its Effect on Dry and Wet CO2 Separations

Healing of Microdefects in SSZ-13 Membranes via Filling with Dye Molecules and Its Effect on Dry and Wet CO2 Separations

Chabazite-Type Zeolite Membranes for Effective CO2 Separation: The Role of Hydrophobicity and Defect Structure

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Healing of Microdefects in SSZ-13 Membranes via Filling with Dye Molecules and Its Effect on Dry and Wet CO₂ Separations

Healing of Microdefects in SSZ-13 Membranes via Filling with Dye Molecules and Its Effect on Dry and Wet CO₂ Separations

Chabazite-Type Zeolite Membranes for Effective CO₂ Separation: The Role of Hydrophobicity and Defect Structure