scholarly journals Halloysite nanotube-based electrospun ceramic nanofibre mat: a novel support for zeolite membranes

2016 ◽  
Vol 3 (12) ◽  
pp. 160552 ◽  
Author(s):  
Zhuwen Chen ◽  
Jiaying Zeng ◽  
Dong Lv ◽  
Jinqiang Gao ◽  
Jian Zhang ◽  
...  
Keyword(s):  
Secondary Growth ◽  
Halloysite Nanotubes ◽  
Sintering Process ◽  
Zeolite Membranes ◽  
Halloysite Nanotube ◽  
Narrow Pore Size Distribution ◽  
Growth Method ◽  
And Performance ◽  
Interconnected Pore

Some key parameters of supports such as porosity, pore shape and size are of great importance for fabrication and performance of zeolite membranes. In this study, we fabricated millimetre-thick, self-standing electrospun ceramic nanofibre mats and employed them as a novel support for zeolite membranes. The nanofibre mats were prepared by electrospinning a halloysite nanotubes/polyvinyl pyrrolidone composite followed by a programmed sintering process. The interwoven nanofibre mats possess up to 80% porosity, narrow pore size distribution, low pore tortuosity and highly interconnected pore structure. Compared with the commercial α-Al 2 O 3 supports prepared by powder compaction and sintering, the halloysite nanotube-based mats (HNMs) show higher flux, better adsorption of zeolite seeds, adhesion of zeolite membranes and lower Al leaching. Four types of zeolite membranes supported on HNMs have been successfully synthesized with either in situ crystallization or a secondary growth method, demonstrating good universality of HNMs for supporting zeolite membranes.

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

Scale-up of NaA zeolite membranes on α-Al2O3 hollow fibers by a secondary growth method with vacuum seeding

2015 ◽  
Vol 23 (7) ◽  
pp. 1114-1122 ◽  
Author(s):  
Yanmei Liu ◽  
Xuerui Wang ◽  
Yuting Zhang ◽  
Yong He ◽  
Xuehong Gu
Keyword(s):  
Scale Up ◽  
Secondary Growth ◽  
Hollow Fibers ◽  
Zeolite Membranes ◽  
Naa Zeolite ◽  
Growth Method ◽  
Α Al2o3

Preliminary Study on the Synthesis of ZIF-8 Membranes via In Situ and Secondary Seeded Growth Methods

2016 ◽  
Vol 1133 ◽  
pp. 649-653 ◽  
Author(s):  
Li Sze Lai ◽  
Yin Fong Yeong ◽  
Kok Keong Lau ◽  
Mohd Shariff Azmi
Keyword(s):  
Secondary Growth ◽  
Dip Coating ◽  
Gas Permeation ◽  
In Situ Growth ◽  
Seeded Growth ◽  
Nitrogen Gas ◽  
Growth Method ◽  
Stage Synthesis ◽  
Growth Methods

In this work, synthesis of ZIF-8 membranes via in situ and secondary seeded growth methods was conducted at the preliminary stage. Synthesis durations were varied at 4 h and 36 h using in situ growth method. For secondary growth, the seeding procedure was applied through rubbing and dip-coating of the seeds on the support. The resultant membranes were characterized using X-ray diffraction (XRD) and scanning electron microscope (SEM). Subsequently, the defects of the resultant membranes were determined using nitrogen gas permeation test. The results showed that, ZIF-8 membrane synthesized using in situ growth method for 4 h exhibited highest crystallinity and lower defects with the nitrogen gas permeance of 5.09 × 10-7 mol/m2·s·Pa. Besides, in situ growth method has shown its potential in synthesizing high quality ZIF-8 membrane through an easy and faster route.

scholarly journals Synthesis and Performance of Deca- Dodecasil 3 Rhombohedral (DDR)-Type Zeolite Membrane In CO2 Separation– A Review

2015 ◽  
Vol 14 (2) ◽  
pp. 48 ◽  
Author(s):  
Muhammad Mubashir ◽  
Yeong Yin Fong ◽  
Lau Kok Keong ◽  
Mohd. Azmi Bin Sharrif
Keyword(s):  
Secondary Growth ◽  
High Energy ◽  
Zeolite Membrane ◽  
Co2 Separation ◽  
Inorganic Membranes ◽  
Zeolite Membranes ◽  
Type Zeolite ◽  
And Performance ◽  
Cryogenic Distillation ◽  
Growth Methods

CO2 capture technologies including absorption, adsorption, and cryogenic distillation are reported. Conventional technologies for CO2 separation from natural gas have several disadvantages including high cost, high maintenance, occupy more space and consume high energy. Thus, membrane technology is introduced to separate CO2 due to their several advantages over conventional separation techniques. Inorganic membranes exhibit high thermal stability, chemical stability, permeability and selectivity for CO2 and CH4 separation as compared to other type of membranes. Zeolite membranes are potential for CO2 separation due to their characteristics such as, well define the pore structure and molecular sieving property. Among the zeolite membranes, DDR membranes exhibit highest selectivity for CO2 and CH4 separation. DDR membranes are synthesized by conventional hydrothermal and secondary growth methods. These methods required very long synthesis duration (25 days) due to extremely low nucleation and crystal growth rate of DDR zeolite. In this review, synthesis and performance of DDR membrane in CO2 separation from CH4 reported by various researchers are discussed. Challenges and upcoming guidelines related to the synthesis DDR membrane and performance of DDR membrane also included.

Preparation of ZSM-5 Zeolite Membranes by Combined Hydrothermal Synthesis and Electrophoretic Deposition

2015 ◽  
Vol 654 ◽  
pp. 47-52 ◽  
Author(s):  
Hideyuki Negishi ◽  
Stephanie Reuß ◽  
Wilhelm Schwieger ◽  
Aldo Roberto Boccaccini
Keyword(s):  
Hydrothermal Synthesis ◽  
Electrophoretic Deposition ◽  
Deposition Time ◽  
Secondary Growth ◽  
Zeolite Membrane ◽  
Zeolite Membranes ◽  
Porous Stainless Steel ◽  
Seeding Method ◽  
Micron Size

The preparation of a ZSM-5 zeolite membrane on porous stainless steel disk by hydrothermal synthesis with electrophoretic deposition (EPD) as a seeding method was investigated. Micron size ZSM-5 crystal powder was seeded by EPD on the support disk by using ZSM-5 powder dispersed in ethanol. The seeded amounts were easily controlled by the deposition time during EPD. The membrane after secondary growth had a low amount of zeolite in comparison with the in situ seeding method and the permeance of single gas such as He, N2 and CO2 was also low in comparison with that of the in situ seeding method.

scholarly journals The influence of chemical parameters on the in-situ metal carbonyl complex formation studied with the fast on-line reaction apparatus (FORA)

2021 ◽  
Vol 109 (4) ◽  
pp. 243-260 ◽  
Author(s):  
Yves Wittwer ◽  
Robert Eichler ◽  
Dominik Herrmann ◽  
Andreas Türler
Keyword(s):  
Metal Carbonyl ◽  
Ambient Air ◽  
Single Atom ◽  
Carbonyl Complex ◽  
Carbonyl Complexes ◽  
On Line ◽  
Carrier Gases ◽  
And Performance ◽  
Atom Chemistry

Abstract A new setup named Fast On-line Reaction Apparatus (FORA) is presented which allows for the efficient investigation and optimization of metal carbonyl complex (MCC) formation reactions under various reaction conditions. The setup contains a 252Cf-source producing short-lived Mo, Tc, Ru and Rh isotopes at a rate of a few atoms per second by its 3% spontaneous fission decay branch. Those atoms are transformed within FORA in-situ into volatile metal carbonyl complexes (MCCs) by using CO-containing carrier gases. Here, the design, operation and performance of FORA is discussed, revealing it as a suitable setup for performing single-atom chemistry studies. The influence of various gas-additives, such as CO2, CH4, H2, Ar, O2, H2O and ambient air, on the formation and transport of MCCs was investigated. O2, H2O and air were found to harm the formation and transport of MCCs in FORA, with H2O being the most severe. An exception is Tc, for which about 130 ppmv of H2O caused an increased production and transport of volatile compounds. The other gas-additives were not influencing the formation and transport efficiency of MCCs. Using an older setup called Miss Piggy based on a similar working principle as FORA, it was additionally investigated if gas-additives are mostly affecting the formation or only the transport stability of MCCs. It was found that mostly formation is impacted, as MCCs appear to be much less sensitive to reacting with gas-additives in comparison to the bare Mo, Tc, Ru and Rh atoms.

scholarly journals Spatially Resolved Experimental Modal Analysis on High-Speed Composite Rotors Using a Non-Contact, Non-Rotating Sensor

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4705
Author(s):  
Julian Lich ◽  
Tino Wollmann ◽  
Angelos Filippatos ◽  
Maik Gude ◽  
Juergen Czarske ◽  
...  
Keyword(s):  
High Speed ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Fiber Reinforced ◽  
Structural Dynamic ◽  
Spatially Resolved ◽  
Glass Fiber Reinforced ◽  
Vibration Responses ◽  
And Performance

Due to their lightweight properties, fiber-reinforced composites are well suited for large and fast rotating structures, such as fan blades in turbomachines. To investigate rotor safety and performance, in situ measurements of the structural dynamic behaviour must be performed during rotating conditions. An approach to measuring spatially resolved vibration responses of a rotating structure with a non-contact, non-rotating sensor is investigated here. The resulting spectra can be assigned to specific locations on the structure and have similar properties to the spectra measured with co-rotating sensors, such as strain gauges. The sampling frequency is increased by performing consecutive measurements with a constant excitation function and varying time delays. The method allows for a paradigm shift to unambiguous identification of natural frequencies and mode shapes with arbitrary rotor shapes and excitation functions without the need for co-rotating sensors. Deflection measurements on a glass fiber-reinforced polymer disk were performed with a diffraction grating-based sensor system at 40 measurement points with an uncertainty below 15 μrad and a commercial triangulation sensor at 200 measurement points at surface speeds up to 300 m/s. A rotation-induced increase of two natural frequencies was measured, and their mode shapes were derived at the corresponding rotational speeds. A strain gauge was used for validation.

Experimental Investigation of Laser Sintering of Conductive Adhesive for Functional Prototypes Produced by Embedding Stereolithography

2014 ◽  
Vol 1038 ◽  
pp. 75-81
Author(s):  
Bernd Niese ◽  
Philipp Amend ◽  
Uwe Urmoneit ◽  
Stephan Roth ◽  
Michael Schmidt
Keyword(s):  
Thermal Damage ◽  
Laser Sintering ◽  
Conductive Adhesive ◽  
Flexible Production ◽  
Sintering Process ◽  
Building Process ◽  
In Situ Generation ◽  
Functional Components

Embedding stereolithography (eSLA) is an additive, hybrid process, which provides a flexible production of 3D components and the ability to integrate electrical and optical conductive structures and functional components within parts. However, the embedding of conductive circuits in stereolithography (SLA) parts assumes usage of process technologies, which enables their direct integration of conductive circuits during the layer-wise building process. In this context, a promising method for in-situ generation of conductive circuits is dispensing of conductive adhesive on the current surface of the SLA part and its subsequent sintering. In this paper, the laser sintering (λ = 355 nm) of conductive adhesive mainly consisting of silver nanoparticles is investigated. The work intends to evaluate the curing behavior of the conductive adhesive, the beam-matter-interactions and the thermal damage of the SLA substrate. The investigations revealed a fast and flexible laser sintering process for the generation of conductive circuits with sufficient electrical conductivity and sufficient current capacity load. In this context, a characterization of the conductive structures is done by measuring their electrical resistance and their potential current capacity load.

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