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

Science ◽  
2009 ◽  
Vol 325 (5940) ◽  
pp. 590-593 ◽  
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.

ChemInform Abstract: Grain Boundary Defect Elimination in a Zeolite Membrane by Rapid Thermal Processing.

ChemInform ◽  
2009 ◽  
Vol 40 (41) ◽  
Author(s):  
Jungkyu Choi ◽  
Hae-Kwon Jeong ◽  
Mark A. Snyder ◽  
Jared A. Stoeger ◽  
Richard I. Masel ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Thermal Processing ◽  
Rapid Thermal Processing ◽  
Zeolite Membrane ◽  
Boundary Defect ◽  
Defect Elimination

Multizone Rapid Thermal Processing to Overcome Challenges in Carbon Nanotube Manufacturing by Chemical Vapor Deposition

2019 ◽  
Author(s):  
Jaegeun Lee ◽  
Moataz Abdulhafez ◽  
Mostafa Bedewy
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Thermal Processing ◽  
Rapid Thermal Processing ◽  
Growth Dynamics ◽  
Chemical Vapor ◽  
Aligned Carbon Nanotubes ◽  
Vertically Aligned ◽  
Scalable Production

Abstract For the scalable production of commercial products based on vertically aligned carbon nanotubes (VACNTs), referred to as CNT forests, key manufacturing challenges must be overcome. In this work, we describe some of the main challenges currently facing CNT forest manufacturing, along with how we address these challenges with our custom-built rapid thermal processing chemical vapor deposition (CVD) reactor. First, the complexity of multistep processes and reaction pathways involved in CNT growth by CVD limits the control on CNT population growth dynamics. Importantly, gas-phase decomposition of hydrocarbons, formation of catalyst particles, and catalytic growth of CNTs are typically coupled. Here, we demonstrated a decoupled recipe with independent control of each step. Second, significant run-to-run variations plague CNT growth by CVD. To improve growth consistency, we designed various measures to remove oxygen-containing molecules from the reactor, including air baking between runs, dynamic pumping down cycles, and low-pressure baking before growth. Third, real-time measurements during growth are needed for process monitoring. We implement in situ height kinetics via videography. The combination of approaches presented here has the potential to transform lab-scale CNT synthesis to robust manufacturing processes.

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 Preparation of Al-Containing ZSM-58 Zeolite Membranes Using Rapid Thermal Processing for CO2/CH4 Mixture Separation

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 623
Author(s):  
Eiji Hayakawa ◽  
Shuji Himeno
Keyword(s):  
Thermal Processing ◽  
Rapid Thermal Processing ◽  
Zeolite Membrane ◽  
Porous Substrate ◽  
Zeolite Membranes ◽  
Template Removal ◽  
Molar Ratios ◽  
Mixture Separation ◽  
Type Zeolite ◽  
Reproducible Method

The synthesis of DDR-type zeolite membranes faces the problem of cracks that occur on the zeolite membrane due to differences in the thermal expansion coefficient between zeolite and the porous substrate during the detemplating process. In this study, Al-containing ZSM-58 zeolite membranes with DDR topology were prepared by rapid thermal processing (RTP), with the aim of developing a reproducible method for preparing DDR zeolite membrane without cracks. Moreover, we verified the influence of RTP before performing conventional thermal calcination (CTC) on ZSM-58 membranes with various silica-to-aluminum (Si/Al) molar ratios. Using the developed method, an Al-containing ZSM-58 membrane without cracks was obtained, along with complete template removal by RTP, and it had higher CO2/CH4 selectivity. An all-silica ZSM-58 membrane without cracks was obtained by only using the ozone detemplating method. ZSM-58 crystals and membranes with various Si/Al molar ratios were analyzed by using Fourier-transform infrared (FTIR) spectroscopy to confirm the effects of RTP treatment. Al-containing ZSM-58 zeolites had higher silanol concentrations than all-silica zeolites, confirming many silanol condensations by RTP. The condensation of silanol forms results in the formation of siloxane bonds and stronger resistance to thermal stress; therefore, RTP caused crack suppression in Al-containing ZSM-58 membranes. The results demonstrate that Al-containing ZSM-58 zeolite membranes with high CO2 permeance and CO2/CH4 selectivity and minimal cracking can be produced by using RTP.

scholarly journals Optimization of Mordenite Membranes Using Sucrose Precursor for Pervaporation of Water-Ethanol Mixtures

Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 160
Author(s):  
Abdulaziz A. Alomair ◽  
Yousef Alqaheem
Keyword(s):  
Pyrolysis Temperature ◽  
Operating Temperature ◽  
Selective Adsorption ◽  
Sucrose Concentration ◽  
Low Cost ◽  
Water Flux ◽  
Separation Performance ◽  
Carbon Membranes ◽  
Adsorption Of Water ◽  
High Separation

Post-treated mordenite membranes were prepared using sucrose (C12H22O11) as a carbon precursor to block any pinholes and defects in the zeolite layer. The pervaporation (PV) process was used to separate ethanol from the water. The effects of the sucrose concentration and the pyrolysis temperature (650–850 °C) were investigated, and the resulting high separation performance compared to those post/pre-treated membranes was reported in the literature. In this study, mordenite carbon membranes yielded a water/ethanol separation factor of 990.37 at a water flux of 9.10 g/m2h. The influence of the operating temperature on the performance of the membrane also was considered. It was concluded that the selective adsorption of water through zeolite pores was achieved. The entire preparation procedure was achieved using a rapid, low-cost preparation process.

Point Defect Reaction in Silicon Wafers by Rapid Thermal Processing at More Than 1300°C Using an Oxidation Ambient

2019 ◽  
Vol 8 (1) ◽  
pp. P35-P40 ◽  
Author(s):  
Haruo Sudo ◽  
Kozo Nakamura ◽  
Susumu Maeda ◽  
Hideyuki Okamura ◽  
Koji Izunome ◽  
...  
Keyword(s):  
Point Defect ◽  
Thermal Processing ◽  
Rapid Thermal Processing ◽  
Silicon Wafers ◽  
Defect Reaction

Modeling, Identification, and Control of Rapid Thermal Processing Systems

1994 ◽  
Vol 141 (11) ◽  
pp. 3200-3209 ◽  
Author(s):  
Charles D. Schaper ◽  
Mehrdad M. Moslehi ◽  
Krishna C. Saraswat ◽  
Thomas Kailath
Keyword(s):  
Thermal Processing ◽  
Rapid Thermal Processing ◽  
And Control
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