Preparation of steam-stable high-silica CHA (SSZ-13) membranes for CO2/CH4 and C2H4/C2H6 separation

Zheng, Yu-Jun; Hu, Na; Wang, Huamei; Bu, Na; Zhang, Fei; Zhou, Rongfei

doi:10.1016/j.memsci.2014.10.048

Cited by 151 publications

(87 citation statements)

References 31 publications

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“…CO 2 permeance decreased and CH 4 permeance was almost independent of pressure (no shown) when the feed pressure from 0.5 MPa to 3 MPa (atmosphere pressure was 0.101 MPa and permeate absolute pressure was 0.103 MPa), resulting into CO 2 /CH 4 selectivity decreased. The similar results were found for the previous pure and best SSZ-13 membranes 24 . The decreases of CO 2 permeance and CO 2 /CH 4 selectivity were mainly due to that the coverage of CO 2 molecule on membrane surface decreased as pressure increased.…”

Section: Co 2 /Ch 4 and Co 2 /N 2 Separationssupporting

confidence: 90%

“…24 The membrane gel had a mole composition of 1.0 3 (Wako) was used as alumina source. The hydrothermal process was carried out at 443 K for 48 h. The as-synthesized membranes were calcined at 753 K for 6 h in air to remove the template.…”

Section: Membrane Preparationmentioning

confidence: 99%

“…However, preparation of highly CO 2 -selective zeolite membranes is a great challenge because the defects are hard to omit during the membrane preparation and calcination. In a previous study, we prepared 10-cm-long tubular SSZ-13 membranes with CO 2 /CH 4 selectivities larger than 150 24 . When we attempted to scale up the synthesis to 40-cm-long membranes, typical CO 2 /CH 4 selectivities of most membranes ranged from 4 to 39 since the non-selective defects were formed during the scale-up synthesis process.…”

Section: Introductionmentioning

confidence: 99%

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Defect-Patching of Zeolite Membranes by Surface Modification Using Siloxane Polymers for CO₂ Separation

Zhou

Wang

et al. 2015

Ind. Eng. Chem. Res.

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Grain boundary defects are normally formed in zeolite membranes during membrane preparation and calcination processes. In this work, a siloxane polymer coating with the imidazole group was grafted on the surface of defective SSZ-13 membranes by chemical liquid deposition to seal the defects. The parameters such as silanization time, polymerization time, monomer type and concentration were optimized.Characterizations including Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM) and energy dispersive x-ray spectroscopy (EDX), showed that siloxane polymers were coated on the surfaces of SSZ-13 crystals and membrane. Six modified membranes showed decreased CO 2 permeance by only 21±5% [average CO 2 permeance of 1.9×10 -7 mol/(m 2 s Pa)] and increased CO 2 /CH 4 selectivity by a factor of 9±3 (average CO 2 /CH 4 selectivity of 108) for an equimolar CO 2 /CH 4 mixture at 298 K. CO 2 /CH 4 and CO 2 /N 2 selectivities of the modified membrane decreased with pressure and temperature. Membrane stability was investigated for a long-time test and exposures to water vapor at temperatures up to 378 K and to some organic solutions. This modification method is also effective in sealing the defects of other zeolite membranes such as AlPO-18 membranes.

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Section: Co 2 /Ch 4 and Co 2 /N 2 Separationssupporting

confidence: 90%

Section: Membrane Preparationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Defect-Patching of Zeolite Membranes by Surface Modification Using Siloxane Polymers for CO₂ Separation

Zhou

Wang

et al. 2015

Ind. Eng. Chem. Res.

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“…5.0 10 -8 mol m -2 s -1 Pa -1 , which is ca. 4-fold smaller compared to the reported values with CHA zeolite membranes having similar zeolitic pore size as Rho zeolite 6) . Rho zeolite is reported to show CO2/N2 adsorption selectivity over 48.…”

Section: Single-gas Permeationcontrasting

confidence: 68%

【Original Contribution】 Preparation of Rho Zeolite Membranes on Tubular Supports

et al. 2016

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Zeolite membranes have been investigated in various applications, including gas separations, such as CO 2 /CH 4 and hydrogen recovery, and liquid separations such as dehydration. MFI type zeolite is the most studied type of zeolite membranes for gas separations, while various other types, such as A(LTA) 1) , Y (FAU) 2) , MFI 3) , T 4) , DDR 5) and CHA 6, 7) membranes have also been reported for their unique CO 2 -selective permeations.Rho zeolite is an aluminosilicate zeolite firstly reported by H.E Robson et al. 8) . Rho zeolite is consisted of -cages connected with double eight-rings (D8Rs) 9) . Rho zeolite has a small pores (0.36 0.36 nm), a relative low Si/Al ratio (2.5 5) and a very high pore volume (0.26 cm 3 g -1 , the pore volumes of 0.36 cm 3 g -1 if cation size is negligible) 10 12) .A remarkably high CO 2 /CH 4 adsorption selectivity of Rho zeolite, 75.2 at approx. 100 kP and at ambient temperature, is reported 13) , which is originated from the smaller zeolitic pore size than the size of CH4 molecule (0.38 nm), strong affinity to CO2 and the high pore Rho zeolite crystals of 0.8 µm and Rho zeolite membranes were hydrothermally synthesized without using organic structure-directing agents (OSDAs). Rho zeolite membranes with thickness of 1 2 µm were formed on the outer surface of porous -Al 2 O 3 tubes via secondary growth method. Membrane showed CO 2 /CH 4 and CO 2 /N 2 ideal selectivities of ca. 6.8 and 2.8, respectively, which are smaller than the reported adsorption selectivities. Rho zeolite membranes showed dehydration performance when water/ethanol and water/isopropanol mixtures were applied.The highest separation factor obtained for water/isopropanol was 1390 with a total flux of 0.77 kg m -2 h -1 when 95wt%isopropanol feed was applied at 348K.

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“…8,21 The feed ow rate was up to 8000 standard mL min À1 (SMLPM) to minimize concentration polarization. 22 The permeate pressure was kept at 0.103 MPa (absolute pressure; atmospheric pressure is 0.101 MPa).…”

Section: Characterization and Separation Performancementioning

confidence: 99%

Improved AlPO-18 membranes for light gas separation

Wang

et al. 2015

J. Mater. Chem. A

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High-quality AlPO-18 membranes were synthesized using low-cost symmetric alumina supports by a single hydrothermal step, and showed to be useful for light gas separation. Single-gas permeances of CO 2 , N 2 , CH 4 and C 3 H 8 decreased with increasing kinetic diameter. Single CO 2 and CH 4 permeance dependence of pressure drop was predicted by the Maxwell-Stefan diffusion model and was in agreement with experimental data. The best AlPO-18 membrane showed smaller-component permeances of 6.5, 6.3 and 1.0 Â 10 À7 mol (m 2 s Pa) À1 (equal to 1940, 1880 and 300 GPU) and mixture selectivities of 220, 45 and 22 for equimolar CO 2 /CH 4 , CO 2 /N 2 and H 2 /CH 4 binary mixtures at room temperature and 0.2 MPa pressure drop, respectively. The effects of temperature and pressure on the membrane's separation performance in the three binary mixtures were discussed.

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Preparation of steam-stable high-silica CHA (SSZ-13) membranes for CO2/CH4 and C2H4/C2H6 separation

Cited by 151 publications

References 31 publications

Defect-Patching of Zeolite Membranes by Surface Modification Using Siloxane Polymers for CO₂ Separation

Defect-Patching of Zeolite Membranes by Surface Modification Using Siloxane Polymers for CO₂ Separation

【Original Contribution】 Preparation of Rho Zeolite Membranes on Tubular Supports

Improved AlPO-18 membranes for light gas separation

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Preparation of steam-stable high-silica CHA (SSZ-13) membranes for CO2/CH4 and C2H4/C2H6 separation

Cited by 151 publications

References 31 publications

Defect-Patching of Zeolite Membranes by Surface Modification Using Siloxane Polymers for CO2 Separation

Defect-Patching of Zeolite Membranes by Surface Modification Using Siloxane Polymers for CO2 Separation

【Original Contribution】 Preparation of Rho Zeolite Membranes on Tubular Supports

Improved AlPO-18 membranes for light gas separation

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Product

Resources

About

Defect-Patching of Zeolite Membranes by Surface Modification Using Siloxane Polymers for CO₂ Separation

Defect-Patching of Zeolite Membranes by Surface Modification Using Siloxane Polymers for CO₂ Separation