scholarly journals Berichtigung: High‐Silica CHA Zeolite Membrane with Ultra‐High Selectivity and Irradiation Stability for Krypton/Xenon Separation

2021 ◽  
Vol 133 (39) ◽  
pp. 21262-21262
Author(s):  
Xuerui Wang ◽  
Tao Zhou ◽  
Ping Zhang ◽  
Wenfu Yan ◽  
Yongguo Li ◽  
...  
2021 ◽  
Vol 60 (39) ◽  
pp. 21094-21094
Author(s):  
Xuerui Wang ◽  
Tao Zhou ◽  
Ping Zhang ◽  
Wenfu Yan ◽  
Yongguo Li ◽  
...  

2021 ◽  
Vol 133 (16) ◽  
pp. 9114-9119
Author(s):  
Xuerui Wang ◽  
Tao Zhou ◽  
Ping Zhang ◽  
Wenfu Yan ◽  
Yongguo Li ◽  
...  

Membranes ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 249
Author(s):  
Yasuhisa Hasegawa ◽  
Chie Abe ◽  
Mayumi Natsui ◽  
Ayumi Ikeda

The polycrystalline CHA-type zeolite layer with Si/Al = 18 was formed on the porous α-Al2O3 tube in this study, and the gas permeation properties were determined using single-component H2, CO2, N2, CH4, n-C4H10, and SF6 at 303–473 K. The membrane showed permeation behavior, wherein the permeance reduced with the molecular size, attributed to the effect of molecular sieving. The separation performances were also determined using the equimolar mixtures of N2–SF6, CO2–N2, and CO2–CH4. As a result, the N2/SF6 and CO2/CH4 selectivities were as high as 710 and 240, respectively. However, the CO2/N2 selectivity was only 25. These results propose that the high-silica CHA-type zeolite membrane is suitable for the separation of CO2 from CH4 by the effect of molecular sieving.


2016 ◽  
Vol 6 (3) ◽  
pp. 713-721 ◽  
Author(s):  
Ryoichi Otomo ◽  
Ulrich Müller ◽  
Mathias Feyen ◽  
Bilge Yilmaz ◽  
Xiangju Meng ◽  
...  

Post-synthetic modification was performed upon an Al-rich OSDA-free Beta to obtain high-silica Beta catalysts for MTO reaction, achieving a high selectivity to light olefins and long catalyst life.


Membranes ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 43 ◽  
Author(s):  
Li Liang ◽  
Meihua Zhu ◽  
Le Chen ◽  
Caijun Zhong ◽  
Yiming Yang ◽  
...  

Continuous and high silica SSZ-13 zeolite membranes were prepared on porous mullite supports from high SiO2/Al2O3 ratio or aluminum-free precursor synthesis gel. Single gas permeance (CO2 and CH4) of the high silica SSZ-13 zeolite membrane was decreased with the SiO2/Al2O3 ratio in the precursor synthesis gel, while the ideal CO2/CH4 selectivity of the membrane was gradually increased. Moreover, effects of synthesis conditions (such as H2O/SiO2 and RNOH/SiO2 ratios of precursor synthesis gel, crystallization time) on the single gas permeance performance of high silica SSZ-13 zeolite membranes were studied in detail. Medium H2O/SiO2 and RNOH/SiO2 ratios in the initial synthesis gel were crucial to prepare the good CO2 perm-selective SSZ-13 zeolite membrane. When the molar composition of precursor synthesis gel, crystallization temperature and time were 1.0 SiO2: 0.1 Na2O: 0.1 TMAdaOH: 80 H2O, 160 °C and 48 h, CO2 permeance and ideal CO2/CH4 selectivity of the SSZ-13 zeolite membrane were 0.98 × 10−7 mol/(m2·s·Pa) and 47 at 25 °C and 0.4 MPa. In addition, the SiO2/Al2O3 ratio of the corresponding SSZ-13 zeolite was 410 by X-ray fluorescence spectroscopy.


Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 229
Author(s):  
Yasuhisa Hasegawa ◽  
Chie Abe ◽  
Ayumi Ikeda

A high-silica chabazite (CHA) type zeolite membrane was prepared on the porous α-Al2O3 support tube by the secondary growth of seed particles. The dehydration performances of the membrane were determined using methanol, ethanol, 2-propanol, acetone, acetic acid, methyl ethyl ketone (MEK), tetrahydrofuran (THF), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and N-methyl-2-pyrolidone (NMP) at 303–373 K. As a result, the dehydration performances of the membrane were categorized to following three types: (1) 2-propanol, acetone, THF, and MEK; (2) ethanol and acetic acid; and (3) methanol, DMF, and DMSO, and NMP. The adsorption isotherms of water, methanol, ethanol, and 2-propanol were determined to discuss the influences of the organic solvents on the permeation and separation performances of the membrane. For 2-propanol, acetone, MEK, and THF solutions, the high permeation fluxes and separation factors were obtained because of the preferential adsorption of water due to molecular sieving. In contrast, the permeation fluxes and separation factors were relatively low for methanol, DMF, and DMSO, and NMP solutions. The lower dehydration performance for the methanol solution was due to the adsorption of methanol. The permeation fluxes for ethanol and acetic acid solution were ca. 1 kg m−2 h−1. The significantly low flux was attributed to the similar molecular diameter to the micropore size of CHA-type zeolite.


2012 ◽  
Vol 165 ◽  
pp. 104-108 ◽  
Author(s):  
Bakri Jufriadi ◽  
Hens Saputra ◽  
Agus Geter E. Sutjipto

High silica MFI zeolite membrane was synthesized by hydrothermal method at 313 K on asymetri pore structure alpha alumina substrate, utilizing natural rice husk as the sources of silica. The top layer of substrate was about 0.1 µm. The calcination was conducted at 773 K to remove the organic template. This membrane has a good stability at high temperature and in organic solvent. The membrane structure was identified by X-ray diffraction (XRD). The permeation of some pure gases was carried out to detect pinhole or cracking by studying mass transfer mechanism in the membrane. The pervaporation performance of as-synthesized membrane showed good results. This process was able to produce fuel grade bioethanol (99.2%) with the separation factor about 14.


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