Peculiarities of the isotopic exchange of the hydrogen of the hydroxyl groups of metal-zeolite catalysts

1975 ◽  
Vol 24 (12) ◽  
pp. 2556-2558
Author(s):  
Kh. M. Minachev ◽  
R. V. Dmitriev ◽  
K. -G. Steinberg ◽  
G. Bremer ◽  
A. N. Detyuk
Keyword(s):  
Isotopic Exchange ◽  
Zeolite Catalysts ◽  
Hydroxyl Groups

Capture and Isotopic Exchange Method for Water and Hydrogen Isotopes on Zeolite Catalysts up to Technical Scale for Pre-Study of Processing Highly Tritiated Water

2015 ◽  
Vol 67 (3) ◽  
pp. 483-486 ◽  
Author(s):  
Robert Michling ◽  
Adalbert Braun ◽  
Ion Cristescu ◽  
Helmut Dittrich ◽  
Manfred Glugla ◽  
...  
Keyword(s):  
Isotopic Exchange ◽  
Tritiated Water ◽  
Hydrogen Isotopes ◽  
Zeolite Catalysts ◽  
Exchange Method

scholarly journals The Exchange Reaction of Deuterium with the Hydroxyl Groups of Zeolite Catalysts

1972 ◽  
Vol 45 (2) ◽  
pp. 366-370 ◽  
Author(s):  
Toshinobu Imanaka ◽  
Yasuaki Okamoto ◽  
Kazunori Takahata ◽  
Shiichiro Teranishi
Keyword(s):  
Exchange Reaction ◽  
Zeolite Catalysts ◽  
Hydroxyl Groups

scholarly journals Theoretical Studies on the Mechanism of deNOx Process in Cu–Zn Bimetallic System—Comparison of FAU and MFI Zeolites

Molecules ◽  
2022 ◽  
Vol 27 (1) ◽  
pp. 300
Author(s):  
Izabela Kurzydym ◽  
Izabela Czekaj
Keyword(s):  
Density Functional ◽  
Co Adsorption ◽  
Computer Calculation ◽  
Zeolite Catalysts ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Hydrothermal Conditions ◽  
Fau Zeolite ◽  
Cu Catalyst ◽  
Mfi Zeolites

In the present study we propose a more promising catalyst for the deNOx process to eliminate harmful nitrogen oxides from the environment. The study was performed with a computer calculation using density functional theory (DFT) based on an ab initio method. Two zeolite catalysts, FAU and MFI, were selected with additional Cu–O–Zn bimetallic dimer adsorbed inside the pores of both zeolites. Based on the analysis of preliminary studies, the most probable way of co-adsorption of nitric oxide and ammonia was selected, which became the initial configuration for the reaction mechanism. Two types of mechanisms were proposed: with hydroxyl groups on a bridged position of the dimer or a hydroxyl group on one of the metal atoms of the dimer. Based on the results, it was determined that the FAU zeolite with a bimetallic dimer and an OH group on the zinc atom was the most efficient configuration with a relatively low energy barrier. The real advantage of the Cu–Zn system over FAU and MFI in hydrothermal conditions has been demonstrated in comparison to a conventional Cu–Cu catalyst.

Hydroxyl Groups in Zeolite Catalysts

Nature ◽  
1968 ◽  
Vol 219 (5158) ◽  
pp. 1040-1041 ◽  
Author(s):  
J. V. SMITH ◽  
J. M. BENNETT
Keyword(s):  
Zeolite Catalysts ◽  
Hydroxyl Groups

Advances in ultramicrotomy for physical sciences applications

1993 ◽  
Vol 51 ◽  
pp. 710-711
Author(s):  
G. McMahon ◽  
T. Malis
Keyword(s):  
Particle Surface ◽  
Zeolite Catalysts ◽  
Physical Sciences ◽  
Pull Out ◽  
Large Particles ◽  
Novel Applications ◽  
Metal Wires ◽  
Frequent Problem ◽  
Specific Orientation ◽  
Diamond Knife

As with all techniques which are relatively new and therefore underutilized, diamond knife sectioning in the physical sciences continues to see both developments of the technique and novel applications.Technique Developments Development of specific orientation/embedding procedures for small pieces of awkward shape is exemplified by the work of Bradley et al on large, rather fragile particles of nuclear waste glass. At the same time, the frequent problem of pullout with large particles can be reduced by roughening of the particle surface, and a proven methodology using a commercial coupling agent developed for glasses has been utilized with good results on large zeolite catalysts. The same principle (using acid etches) should work for ceramic fibres or metal wires which may only partially pull out but result in unacceptably thick sections. Researchers from the life sciences continue to develop aspects of embedding media which may be applicable to certain cases in the physical sciences.

Bleaching ability of pre-hydrolyzed pulps in the context of a biorefinery mill

TAPPI Journal ◽  
2013 ◽  
Vol 12 (11) ◽  
pp. 49-53 ◽  
Author(s):  
CHRISTINE CHIRAT ◽  
LUCIE BOIRON ◽  
DOMINIQUE LACHENAL
Keyword(s):  
Carbon Content ◽  
Acid Hydrolysis ◽  
13C Nmr ◽  
Kraft Lignin ◽  
Kappa Number ◽  
Hydroxyl Groups ◽  
Kraft Pulps ◽  
Quaternary Carbon ◽  
Oxygen Delignification

Autohydrolysis and acid hydrolysis treatments were applied on mixed softwood chips. The cooking ability was studied by varying the alkali and duration of the cook. Pulps with kappa numbers varying from 30 to 70 were obtained. The bleaching ability of these pulps was studied and compared to control kraft pulps. The prehydrolyzed pulps were shown to be more efficiently delignified by oxygen than the control kraft pulps starting from the same kappa number. Furthermore, the final bleaching was also easier for these pulps. It was also shown that extensive oxygen delignification applied on high-kappa pre-hydrolyzed pulps could be a way to improve the overall yield, which is a prerequisite for the development of such biorefinery concepts. Lignin was isolated from the control kraft and the two pre-hydrolyzed kraft pulps and analyzed by 13C NMR. Lignins from pre-hydrolyzed kraft pulps had similar free phenolic groups content to the control kraft lignin, but their aliphatic hydroxyl groups and β-O-4 content were lower than for the control lignin. The quaternary carbon content was the same for all the samples.

Sign in / Sign up

Export Citation Format

Share Document