scholarly journals Single Gas Permeance Performance of High Silica SSZ-13 Zeolite Membranes

Membranes ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 43 ◽  
Author(s):  
Li Liang ◽  
Meihua Zhu ◽  
Le Chen ◽  
Caijun Zhong ◽  
Yiming Yang ◽  
...  
Keyword(s):  
Fluorescence Spectroscopy ◽  
Zeolite Membrane ◽  
Crystallization Time ◽  
Zeolite Membranes ◽  
X Ray ◽  
Synthesis Conditions ◽  
Precursor Synthesis ◽  
Porous Mullite ◽  
High Silica ◽  
The Ideal

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.

scholarly journals Effects of Seed Crystals on the Growth and Catalytic Performance of TS-1 Zeolite Membranes

Membranes ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 41
Author(s):  
Wenjuan Ding ◽  
Sitong Xiang ◽  
Fei Ye ◽  
Tian Gui ◽  
Yuqin Li ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
High Performance ◽  
Catalytic Performance ◽  
Zeolite Membrane ◽  
Medium Size ◽  
Zeolite Membranes ◽  
Seed Crystals ◽  
Ratio Size ◽  
Porous Mullite ◽  
Size And Morphology

Dense and good catalytic performance TS-1 zeolite membranes were rapidly prepared on porous mullite support by secondary hydrothermal synthesis. The properties of seed crystals were very important for the preparation of high-catalytic performance TS-1 zeolite membranes. Influences of seed crystals (Ti/Si ratios, size, morphology, and zeolites concentration of the seed suspension) on the growth and catalytic property of TS-1 zeolite membranes were investigated in details. High Ti/Si ratio, medium-size, and morphology of the seed crystals were critical for preparing the high-performance TS-1 zeolite membrane. Compared with the bi-layer TS-1 zeolite membrane (inner and outer of the mullite tube), the mono-layer TS-1 zeolite membrane had a better catalytic performance for Isopropanol IPA oxidation with H2O2. When the Ti/Si ratio, size, and morphology of the TS-1 zeolites were 0.030, 300 nm, ellipsoid, and the zeolites concentration of the seed suspension was 5%, the IPA conversion, and flux through the TS-1 zeolite membrane were 98.23% and 2.58 kg·m−2·h−1, respectively.

scholarly journals Synthesis of high-silica ZSM-5 with seeds in the presence of ethanol and amine

Cerâmica ◽  
2019 ◽  
Vol 65 (375) ◽  
pp. 378-387
Author(s):  
T. R. D. Mendonça ◽  
J. R. Santos ◽  
L. R. A. Sarmento ◽  
D. C. M. Silva ◽  
O. M. S. Cysneiros ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Organic Compounds ◽  
Nitrogen Adsorption ◽  
Structure Directing Agent ◽  
X Ray ◽  
Synthesis Conditions ◽  
Combined Use ◽  
Cracking Reaction ◽  
High Silica ◽  
Alternative Structure

Abstract The possibility of crystallization of ZSM-5 with high Si/Al ratio was evaluated through the combined use of crystallization seeds and organic compounds that are not conventional directing agents for ZSM-5 (ethanol, methylamine, ethylamine, propylamine, butylamine, isopropylamine and diethylamine) in order to find a less toxic and costly route of synthesis. In addition, the influence of the stirring during the crystallization step on the properties of the ZSM-5 obtained in these synthesis conditions was verified. The obtained zeolites were analyzed by X-ray diffractometry in order to understand the effects of the templates. The analyses of NH3-TPD, nitrogen adsorption, SEM, and TG/DTA were performed for the samples with better crystallinity. The procedure was successfully employed for the synthesis of MFI samples using propylamine as an alternative structure-directing agent. Its mean crystallite size ranged from 23 to 24 nm and was efficient in the cracking reaction of n-hexane.

MFI Zeolite Membrane from Rice Husk for Biofuels Production

2012 ◽  
Vol 165 ◽  
pp. 104-108 ◽  
Author(s):  
Bakri Jufriadi ◽  
Hens Saputra ◽  
Agus Geter E. Sutjipto
Keyword(s):  
Rice Husk ◽  
Membrane Structure ◽  
Zeolite Membrane ◽  
Organic Template ◽  
X Ray Diffraction ◽  
Mfi Zeolite ◽  
X Ray ◽  
Mass Transfer Mechanism ◽  
High Silica ◽  
Alpha Alumina

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.

scholarly journals A Simple Method of Preparation of High Silica Zeolite Y and Its Performance in the Catalytic Cracking of Cumene

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Zhanjun Liu ◽  
Chenxi Shi ◽  
Dan Wu ◽  
Shixuan He ◽  
Bo Ren
Keyword(s):  
Zeolite Y ◽  
Sodium Aluminate ◽  
Crystallization Time ◽  
X Ray Diffraction ◽  
Simple Method ◽  
X Ray ◽  
Surface Areas ◽  
Xrf Scanning ◽  
High Silica ◽  
Adsorption Desorption

A series of high silicon zeolites Y were prepared through direct synthetic method by using silica sol as the silicon source and sodium aluminate as the aluminum source. The effects of alkalinity and crystallization time of the process of synthesis were investigated. To separately reveal the crystalline structure, element content, morphology, and surface areas, the as-synthesized zeolite Y was characterized by powder X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), and N2adsorption-desorption isotherms (BET). The results show the as-synthesized zeolite Y with high relative crystallization and uniform morphology; the SiO2/Al2O3ratio was about 4.54~6.46. For an application, the zeolite cracking activity was studied with cumene as the probe molecules.

scholarly journals Synthesis of 4A Zeolite from Kaolinite-Type Pyrite Flotation Tailings (KPFT)

Minerals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 338 ◽  
Author(s):  
Yating Cui ◽  
Yu Zheng ◽  
Weiqing Wang
Keyword(s):  
Hydrothermal Synthesis ◽  
Exchange Capacity ◽  
Crystallization Time ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Relative Crystallinity ◽  
Flotation Tailings ◽  
X Ray ◽  
Synthesis Conditions ◽  
4A Zeolite

As a solid waste, kaolinite-type pyrite flotation tailings (KPFT) are a type of low-quality kaolin that contain impurities, such as iron and titanium. In this study, KPFT were calcined at 800 °C for two hours. The calcined production (CKPFT), which is mainly metakaolin, was used as the silicon and aluminum source to synthesize 4A zeolite (Na12[(AlO2)12(SiO2)12]·27H2O) via hydrothermal synthesis. The optimal hydrothermal synthesis conditions were determined from X-ray diffraction phase analysis, relative crystallinity (RC), and cation ion exchange capacity (CEC). The optimal hydrothermal synthesis conditions were determined to be a ratio of 5 g CKPFT, 6.5 g NaOH, 65 mL H2O, crystallization temperature 110 °C, and crystallization time of three hours. Under the optimal hydrothermal synthesis conditions, the RC and CEC of the synthesized 4A zeolite were 40.77% and 210.32 mg CaCO3·g−1, respectively. Further characterizations including pore size distribution, scanning electron microscopy, energy dispersive X-ray, thermogravimetry-differential scanning calorimetry, and Fourier transform infrared spectroscopy were performed. The results revealed that impurities in KPFT do not affect the synthesis of 4A zeolite. The surface morphology of the synthesized 4A zeolite was composed of chamfered-edged cubes with a particle size of one to three μm that was thermally stable up to approximately 890 °C.

scholarly journals Synthesis of FAU-Type Zeolite Membranes with Antimicrobial Activity

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3414
Author(s):  
T. Jean Daou ◽  
Thomas Dos Santos ◽  
Habiba Nouali ◽  
Ludovic Josien ◽  
Laure Michelin ◽  
...  
Keyword(s):  
Heating Temperature ◽  
Mercury Porosimetry ◽  
Antimicrobial Properties ◽  
Zeolite Membrane ◽  
X Ray Diffraction ◽  
Zeolite Membranes ◽  
E Coli ◽  
Type Zeolite ◽  
Α Al2o3 ◽  
The Ideal

In this study, a layer of a pure and dense phase of FAU-type zeolite was synthesized directly on the surface of α-Al2O3 plane macroporous support. Before hydrothermal synthesis, a step of cleaning of the support by an anionic detergent was performed, a roughness surface is created, allowing the anchoring of the zeolite nuclei and then their growth, favoring in this sense the formation of a homogeneous zeolite layer. The obtained membranes were fully characterized using X-ray diffraction analysis (XRD), nitrogen sorption, scanning electron microscopy (SEM), and mercury porosimetry. After 24 h of thermal treatment at 75 °C, a homogeneous zeolite layer composed of bipyramidal crystals of FAU-type zeolite is obtained with a thickness of about 2.5 µm. No obvious defects or cracks can be observed. It was found that the increase in heating temperature could lead to the appearance of an impurity phase, GIS-type zeolite. Then the ideal zeolite membrane was exchanged with Ag+ or Zn2+ cations to studies their antimicrobial properties. Zeolites membranes exchanged with Ag+ showed an agar-diffusive bactericidal activity against gram negative Escherichia coli (E. coli) bacteria. Zn2+ exchanged zeolite membrane presented a bacteriostatic activity that is less diffusive in agar. As expected, non-exchanged zeolite membrane (in its Na+ form) have no effect on bacterial activity. This process is particularly interesting for the synthesis of a good quality FAU-type zeolite membranes with antimicrobial properties.

X-Ray Analysis of Frozen Hydrated Sections:The Unconventional Approach

1982 ◽  
Vol 40 ◽  
pp. 754-757
Author(s):  
R. Beeuwkes ◽  
A. Saubermann ◽  
P. Echlin ◽  
S. Churchill
Keyword(s):  
Ratio Method ◽  
Frozen Sections ◽  
Technical Problems ◽  
Sample Handling ◽  
X Ray ◽  
Common Group ◽  
Ideal Method ◽  
Classic Paper ◽  
Physical Principles ◽  
The Ideal

Fifteen years ago, Hall described clearly the advantages of the thin section approach to biological x-ray microanalysis, and described clearly the ratio method for quantitive analysis in such preparations. In this now classic paper, he also made it clear that the ideal method of sample preparation would involve only freezing and sectioning at low temperature. Subsequently, Hall and his coworkers, as well as others, have applied themselves to the task of direct x-ray microanalysis of frozen sections. To achieve this goal, different methodological approachs have been developed as different groups sought solutions to a common group of technical problems. This report describes some of these problems and indicates the specific approaches and procedures developed by our group in order to overcome them. We acknowledge that the techniques evolved by our group are quite different from earlier approaches to cryomicrotomy and sample handling, hence the title of our paper. However, such departures from tradition have been based upon our attempt to apply basic physical principles to the processes involved. We feel we have demonstrated that such a break with tradition has valuable consequences.

High Resolution Study of Polytypism: Application to SiC and Au3 Mn

1982 ◽  
Vol 40 ◽  
pp. 540-541
Author(s):  
G. Van Tendeloo ◽  
J. Van Landuyt ◽  
S. Amelinckx
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Stacking Sequence ◽  
X Ray ◽  
Powerful Technique ◽  
Resolution Study ◽  
The Ideal

Polytypism has been studied for a number of years and a wide variety of stacking sequences has been detected and analysed. SiC is the prototype material in this respect; see e.g. Electron microscopy under high resolution conditions when combined with x-ray measurements is a very powerful technique to elucidate the correct stacking sequence or to study polytype transformations and deviations from the ideal stacking sequence.

Sign in / Sign up

Export Citation Format

Share Document