scholarly journals Formation Process of Columnar Grown (101)-Oriented Silicalite-1 Membrane and Its Separation Property for Xylene Isomer

Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 949
Author(s):  
Motomu Sakai ◽  
Takuya Kaneko ◽  
Yukichi Sasaki ◽  
Miyuki Sekigawa ◽  
Masahiko Matsukata
Keyword(s):  
Secondary Growth ◽  
Microscopic Analysis ◽  
Separation Performance ◽  
Membrane Thickness ◽  
Alumina Support ◽  
Separation Factors ◽  
Growth Method ◽  
Thin Part ◽  
Xylene Separation ◽  
Xylene Isomer

Silicalite-1 membrane was prepared on an outer surface of a tubular α-alumina support by a secondary growth method. Changes of defect amount and crystallinity during secondary growth were carefully observed. The defect-less well-crystallized silicalite-1 membrane was obtained after 7-days crystallization at 373 K. The silicalite-1 membrane became (h0l)-orientation with increasing membrane thickness, possibly because the orientation was attributable to “evolutionally selection”. The (h0l)-oriented silicalite-1 membrane showed high p-xylene separation performance for a xylene isomer mixture (o-/m-/p-xylene = 0.4/0.4/0.4 kPa). The p-xylene permeance through the membrane was 6.52 × 10−8 mol m−2 s−1 Pa−1 with separation factors αp/o, αp/m of more than 100 at 373 K. As a result of microscopic analysis, it was suggested that a very thin part in the vicinity of surface played as effective separation layer and could contribute to high permeation performance.

scholarly journals Study the Effect of Seeding Suspension Concentration of DD3R Particles on the Modified Surface of Α-Alumina Support for Preparing DD3R Zeolite Membrane with High Quality

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Aynaz Meshkat ◽  
Mohammad Javad Vaezi ◽  
Ali Akbar Babaluo
Keyword(s):  
Secondary Growth ◽  
Dip Coating ◽  
Sem Analysis ◽  
Gas Permeation ◽  
Zeolite Membrane ◽  
Alumina Support ◽  
Suspension Concentration ◽  
Coating Method ◽  
Growth Method ◽  
Modified Surface

In this study, seeding of DD3R particles as an important step in the synthesis of DD3R membrane with secondary growth method was investigated. Dip-coating method is used for seeding of DD3R particles on the modified surface of α-alumina supports. 0.1, 0.2 and 0.3 wt% aqueous suspensions of the DD3R seeds were prepared and each support was coated three times with dipping time of 240 s. Scanning electron microscopy (SEM) analysis was used for the investigation of the quality of seed layer formed on the support. It is shown that the uniform layer of seeds was formed with 0.2 wt% seed suspension concentration. DD3R zeolite membrane was synthesized via hydrothermal method on the support seeded with 0.2 wt% seed suspension concentration. The X-ray diffraction and SEM analysis confirmed the synthesis of uniform DD3R zeolite membrane layer on the support which can be due to the uniform distribution of the DD3R seeds. Single gas permeation tests of N2, CO2 and CH4 were carried out, so that good perm-selectivity for gas mixtures was observed.

scholarly journals Preparation of PHI Zeolite Membrane with High Separation Performance by the Secondary Growth Method

2011 ◽  
Vol 27 (10) ◽  
pp. 2493-2498
Author(s):  
YUAN Wen-Hui ◽  
◽  
CHANG Ran-Ran ◽  
LIU Xiao-Chen ◽  
LI Li ◽  
...  
Keyword(s):  
Secondary Growth ◽  
Zeolite Membrane ◽  
Separation Performance ◽  
Growth Method ◽  
High Separation

scholarly journals Rapid microwave-assisted seeding and secondary growth synthesis of ZIF-8 membrane for propylene/propane separation

2021 ◽  
Vol 63 (8) ◽  
pp. 44-48
Author(s):  
Kim Minh Nguyen ◽  
◽  
Nguyen Tien Tran ◽  
Keyword(s):  
Secondary Growth ◽  
Separation Performance ◽  
Atmospheric Conditions ◽  
Zeolitic Imidazolate Framework ◽  
Alumina Support ◽  
Long Term Stability ◽  
Microwave Assisted ◽  
Wide Range ◽  
Seeding Strategy ◽  
Separation Performances

Owing to their permanent porosity, diverse topology structures, and coordination factors combined with chemical tunability, the zeolitic imidazolate framework (ZIF) has shown great potential for the effective separation of hydrocarbon mixtures. In this work, the authors presented a simple microwave-assisted seeding strategy to rapidly prepare a seed layer for the synthesis of high-quality ZIF-8 membranes for propylene/propane separation. The resulted membranes grown on planar alumina support displayed excellent separation performances for a wide range of propylene/propane mixtures. The membrane displayed a propylene/propane separation factor of 70 and propylene permeance of 105×10-10 mol.m-2s-1Pa-1. Long-term stability test also showed stable gas permeance and separation performance of the ZIF-8 membranes in both atmospheric conditions and propylene/propane mixture stream.

scholarly journals Tailoring the Stabilization and Pyrolysis Processes of Carbon Molecular Sieve Membrane Derived from Polyacrylonitrile for Ethylene/Ethane Separation

Membranes ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 93
Author(s):  
DaeHun Kim ◽  
YongSung Kwon ◽  
Jung-Hyun Lee ◽  
Seong-Joong Kim ◽  
You-In Park
Keyword(s):  
Molecular Sieve ◽  
Pyrolysis Temperature ◽  
Separation Performance ◽  
Carbon Molecular Sieve ◽  
Alumina Support ◽  
Soaking Time ◽  
Polymer Precursors ◽  
Pre Treatment ◽  
Excellent Thermal Property ◽  
Pyrolysis Processes

For ethylene/ethane separation, a CMS (carbon molecular sieve) membrane was developed with a PAN (polyacrylonitrile) polymer precursor on an alumina support. To provide an excellent thermal property to PAN precursor prior to the pyrolysis, the stabilization as a pre-treatment process was carried out. Tuning the stabilization condition was very important to successfully preparing the CMS membrane derived from the PAN precursor. The stabilization and pyrolysis processes for the PAN precursor were finely tuned, and optimized in terms of stabilization temperature and time, as well as pyrolysis temperature, heating rate, and soaking time. The PAN stabilized at >250 °C showed improved thermal stability and carbon yield. The CMS membrane derived from stabilized PAN showed reasonable separation performance for ethylene permeance (0.71 GPU) and ethylene/ethane selectivity (7.62), respectively. Increasing the pyrolysis temperature and soaking time gave rise to an increase in the gas permeance, and a reduction in the membrane selectivity. This trend was opposite to that for the CMS membranes derived from other polymer precursors. The optimized separation performance (ethylene permeance of 2.97 GPU and ethylene/ethane selectivity of 7.25) could be achieved at the pyrolysis temperature of 650 °C with a soaking time of 1 h. The separation performance of the CMS membrane derived from the PAN precursor was comparable to that of other polymer precursors, and surpassed them regarding the upper bound trade off.

Synthesis and Characterization of NaA Zeolite Membranes Prepared by the Secondary Growth Method: A Research-Based Comprehensive Experiment

Daxue Huaxue ◽  
2018 ◽  
Vol 33 (9) ◽  
pp. 69-74
Author(s):  
Liangqing LI ◽  
◽  
Qipeng SONG ◽  
Jinjian ZHANG ◽  
Chenchen DAI ◽  
...  
Keyword(s):  
Secondary Growth ◽  
Synthesis And Characterization ◽  
Zeolite Membranes ◽  
Naa Zeolite ◽  
Growth Method

scholarly journals Preparation and Progress in Application of Gold Nanorods

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Liqing Meng ◽  
Jinsheng Zhang ◽  
Huiqin Li ◽  
Weiwei Zhao ◽  
Tonggang Zhao
Keyword(s):  
Optical Properties ◽  
Gold Nanorods ◽  
Secondary Growth ◽  
Disease Diagnosis ◽  
Information Storage ◽  
Hard Template ◽  
Comprehensive Review ◽  
Growth Method ◽  
Seed Method ◽  
Hard Template Method

Gold nanorods (Au NRs) have attracted extensive research interest due to their unique optical properties, adjustable aspect ratio, and easy surface modification in the fields of biosensing, bioimaging, and disease diagnosis and detection. In this review, we present a comprehensive review of various methods for preparing gold nanorods including hard template method, electrochemistry method, photochemistry method, seed-mediated growth method, secondary growth method, and amorphous seed method. The unique optical properties of the gold nanorods and its applications in biomedical, detection, catalysis, and information storage will also be discussed in detail.

Synthesis of MCM-22 Zeolite Membrane on a Porous Alumina Support

2014 ◽  
Vol 805 ◽  
pp. 272-278 ◽  
Author(s):  
Antonielly dos S. Barbosa ◽  
Antusia dos S. Barbosa ◽  
Meiry Glaucia F. Rodrigues
Keyword(s):  
Porous Alumina ◽  
Mercury Porosimetry ◽  
Secondary Growth ◽  
Molecular Size ◽  
Zeolite Membrane ◽  
X Ray Diffraction ◽  
Alumina Support ◽  
X Ray ◽  
Ceramic Support ◽  
Separation Of Mixtures

Much interest has been aroused in the application in industrial processes using zeolite membrane, due to its crystalline structure, and narrow pore diameters. These features enable the continuous separation of mixtures based on differences in molecular size and shape and also based on different adsorption properties. This paper reports the synthesis of MCM-22 zeolite membrane, using the method of secondary growth. The MCM-22 zeolite was synthesized by the hydrothermal method and characterized by spectroscopy Energy Dispersive X-ray (EDX), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM).The ceramic support (α-alumina) was prepared using the technique of forming powder and then subjected to the sintering temperature of 1400 °C/1h and characterized by XRD. The zeolite membrane preparation was performed by the method of secondary growth and characterized by XRD, SEM and mercury porosimetry. The obtained zeolite membrane could be confirmed by X-ray diffraction. From, the obtained SEM pictures it was possible to observe the formation of a homogeneous film on the zeolite surface of the ceramic support (α-alumina).

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