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

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.

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Preparation of Membrane Zeolite MCM-22 and Evaluation Process Oil/Water Separation

Materials Science Forum ◽

10.4028/www.scientific.net/msf.820.605 ◽

2015 ◽

Vol 820 ◽

pp. 605-608

Author(s):

A. Santos Barbosa ◽

A.S. Barbosa ◽

M.G.F. Rodrigues

Keyword(s):

Continuous Flow ◽

Membrane Separation ◽

Secondary Growth ◽

Evaluation Process ◽

Zeolite Membrane ◽

Water Separation ◽

Oil Emulsion ◽

X Ray ◽

Growth Method ◽

Oil Water

The objective of this work was prepared by secondary growth method, and evaluate the ability of the MCM-22 zeolite membrane separation system in oil / water in a continuous flow system. The zeolite membrane MCM-22 was characterized by different techniques: X-Ray Spectrometry Energy Dispersive (EDX), X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). A continuous flow was used. The test for measuring mass flow of water / oil emulsion was conducted in peristaltic pump, wherein the membrane zeolite MCM-22 was tested. Through the results, we can observe the efficiency of the method used in the preparation of zeolite membrane and was also observed that the zeolite MCM-22 membrane, obtained by secondary growth method showed removal percentages equivalent to the standards required by Resolution 392 CONAMA.

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Grain Boundary Defect Elimination in a Zeolite Membrane by Rapid Thermal Processing

Science ◽

10.1126/science.1176095 ◽

2009 ◽

Vol 325 (5940) ◽

pp. 590-593 ◽

Cited By ~ 204

Author(s):

Jungkyu Choi ◽

Hae-Kwon Jeong ◽

Mark A. Snyder ◽

Jared A. Stoeger ◽

Richard I. Masel ◽

...

Keyword(s):

Grain Boundary ◽

Thermal Processing ◽

Molecular Sieve ◽

Rapid Thermal Processing ◽

Zeolite Membrane ◽

Separation Performance ◽

Transport Pathways ◽

Scalable Production ◽

Defect Elimination ◽

High Separation

Microporous molecular sieve catalysts and adsorbents discriminate molecules on the basis of size and shape. Interest in molecular sieve films stems from their potential for energy-efficient membrane separations. However, grain boundary defects, formed in response to stresses induced by heat treatment, compromise their selectivity by creating nonselective transport pathways for permeating molecules. We show that rapid thermal processing can improve the separation performance of thick columnar films of a certain zeolite (silicalite-1) by eliminating grain boundary defects, possibly by strengthening grain bonding at the grain boundaries. This methodology enables the preparation of silicalite-1 membranes with high separation performance for aromatic and linear versus branched hydrocarbon isomers and holds promise for realizing high-throughput and scalable production of these zeolite membranes with improved energy efficiency.

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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

Emerging Science Journal ◽

10.28991/esj-2018-01127 ◽

2018 ◽

Vol 2 (1) ◽

Cited By ~ 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.

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Facile Preparation of Bilayer Titanium Silicate (TS-1) Zeolite Membranes by Periodical Secondary Growth

Coatings ◽

10.3390/coatings9120850 ◽

2019 ◽

Vol 9 (12) ◽

pp. 850

Author(s):

Qi Zhang ◽

Yong Liu ◽

Xuguang Liu ◽

Laibo Ma

Keyword(s):

Room Temperature ◽

Secondary Growth ◽

Contact Angle Measurement ◽

Angle Measurement ◽

Zeolite Membrane ◽

Distribution Analysis ◽

The Novel ◽

Titanium Silicate ◽

Water Contact ◽

Growth Method

A facile periodical secondary growth method, based on conventional secondary growth, is proposed to prepare bilayer TS-1 membranes. The novel periodical secondary growth consists of two or several periods, which involve three steps: the temperature is programmed to a desired crystallization temperature as the first stage, followed by holding for a certain duration, and finally cooling to room temperature. This periodical crystallization model enables a bilayer TS-1 membrane to be produced, while the conventional secondary growth method produces a monolayer TS-1 membrane. The bilayer TS-1 membrane exhibits a superior defect-free structure and hydrophobic properties, as illustrated by SEM, gas permeance, pore size distribution analysis, and water contact angle measurement. It displays an earlier desalination separation factor compared to the monolayer TS-1 membrane. This work demonstrates that the periodical secondary growth is an advanced approach for preparing a bilayer zeolite membrane with excellent properties.

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Catalytic combustion of isopropanol over Co–ZSM-5 zeolite membrane catalysts in structured fixed-bed reactor

Royal Society Open Science ◽

10.1098/rsos.180587 ◽

2018 ◽

Vol 5 (8) ◽

pp. 180587 ◽

Cited By ~ 2

Author(s):

Xiaotong Zhang ◽

Ying Yan

Keyword(s):

Catalytic Combustion ◽

Secondary Growth ◽

Fixed Bed ◽

Space Velocity ◽

Catalytic Performance ◽

Zeolite Membrane ◽

Fixed Bed Reactor ◽

Impregnation Method ◽

Feed Concentration ◽

Growth Method

Catalytic combustion of isopropanol in the structured fixed-bed reactor was investigated over Co–ZSM-5 zeolite membrane catalysts. Firstly, ZSM-5 zeolite membrane catalysts with different Si/Al ratios were coated onto the surface of stainless steel fibres via secondary growth method and wet lay-up paper-making method. Then, cobalt oxides were loaded onto the zeolite membranes by impregnation method. The performance of catalytic combustion of isopropanol was conducted over the prepared zeolite membrane catalysts, and the experimental results showed that the catalyst with infinite Si/Al ratio has the highest catalytic activity for the combustion with the lowest T 90 of isopropanol (285°C). Finally, the effects of bed structure, feed concentration, gas hourly space velocity and reaction temperature on the catalytic performance were investigated to analyse the kinetics of isopropanol over the catalyst with infinite Si/Al ratio in the structured fixed-bed reactor. The results showed that the longer residence time could cause higher reaction contact efficiency of isopropanol combustion. T 90 of isopropanol can be dramatically decreased by 105°C in the fixed-bed reactor packed with Co–ZSM-5 zeolite membrane catalysts, compared to the fixed-bed reactor packed with granular catalyst.

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Synthesis of Potassium Ion Sieve Membrane by Secondary Growth Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.396-398.2279 ◽

2011 ◽

Vol 396-398 ◽

pp. 2279-2284

Author(s):

Li Hui Sun ◽

Jun Sheng Yuan ◽

Yun Peng Fu ◽

Jin Hou ◽

Kong Xiu Zhu

Keyword(s):

Hydrothermal Synthesis ◽

Secondary Growth ◽

Potassium Ion ◽

Zeolite Membrane ◽

Ammonium Bromide ◽

Tetrabutyl Ammonium Bromide ◽

Tetrabutyl Ammonium ◽

Growth Method ◽

Α Al2o3

potassium ionic sieve membrane was synthesized employing the secondary hydrothermal synthesis using tetrabutyl ammonium bromide as templates on the porous α-Al2O3 support.The zeolite membrane were characterized by XRD and SEM. The results show that the prepared membranes is potassium ionic sieve membrane, dense and continuous membrane could be obtained after crystallization synthesis was carried out at 423K for 12h and for three times.

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