Catalytic Decomposition of Perfluorocompounds

1997 ◽  
Vol 497 ◽  
Author(s):  
S. Kanno ◽  
S. Ikeda ◽  
H. Yamashita ◽  
S. Azuhata ◽  
S. Irie ◽  
...  
Keyword(s):  
Greenhouse Gases ◽  
High Activity ◽  
Mixed Oxides ◽  
Catalytic Decomposition ◽  
Waste Gas ◽  
Process Waste ◽  
Dry Etch ◽  
Decomposition System

ABSTRACTIt is becoming increasingly important to decompose PFCs (Perfluorocompounds), which are powerful greenhouse gases. The process of catalytic decomposition is expected to be effective in operating at lower temperatures if catalysts of high activity and durability are developed. The decomposition activities of PFC with H2O was investigated using several catalysts. It was found that PFC decomposition activity was related to the reactivity of fluorine and the formation of mixed oxides. Using the catalyst we have developed, CF4 was decomposed with conversion above 99.9% over 1988h. Furthermore, another PFC was decomposed over the catalyst. The order of the conversion was CHF3 > CF4 > C2F6. The catalytic decomposition system can use the treatment of PFCs in dry etch process waste gas.

The catalytic decomposition of ethers on evaporated tungsten films

1968 ◽  
Vol 302 (1470) ◽  
pp. 385-398 ◽  
Keyword(s):  
High Activity ◽  
Water Vapour ◽  
Metal Surface ◽  
Initial Period ◽  
Catalytic Decomposition ◽  
Zero Order ◽  
Transitional Period ◽  
Zero Order Kinetics ◽  
Rate Of Reaction ◽  
Combined Action

The reactions of diethyl and di- n -propyl ethers have been studied in the presence of hydrogen on evaporated films of tungsten. In the temperature range from 200 to 260°C ethane and ethylene were formed from diethyl ether and small amounts of butenes were also produced. Each film had an initial high activity, especially for the formation of ethane, but the activity declined to a steady value during a transitional period. Subsequently, the decomposition of the ether occurred with zero order kinetics. A similar transitional period was observed during the decomposition of di- n -propyl ether but the change in the character of the reactions was more marked. Propane and propylene were formed initially, but very little further propane was produced after the initial period. If the surface of the tungsten was oxidized before exposure to ether, a high activity for the dehydration of the propyl ether was observed. Evidence from a number of experiments showed that irreversible changes were occurring to the catalyst during the transitional periods in which the metal surface was being converted to a different type of surface under the combined action of the ether and water vapour which was either added or formed by reaction. Most of the results could be interpreted on the assumption that two types of surface were formed—an oxidized surface of high activity for dehydration and an inactive surface covered by strongly adsorbed hydrocarbon residues. Subsidiary experiments were carried out with n -propanol on oxidized tungsten and evidence was found that the dehydration of the alcohol which was strongly adsorbed probably controlled the rate of reaction of the ether.

scholarly journals Development of Catalytic Decomposition System for Chlorofluorocarbon

1998 ◽  
Vol 118 (9) ◽  
pp. 1257-1262
Author(s):  
Shuichi Kanno ◽  
Shin Tamata ◽  
Hisao Yamashita ◽  
Shigeru Azuhata
Keyword(s):  
Catalytic Decomposition ◽  
Decomposition System

scholarly journals Biosynthesis of Zinc Sulfide Quantum Dots Using Waste Off-Gas from Metal Bioremediation Process

2015 ◽  
Vol 1130 ◽  
pp. 555-559
Author(s):  
Jimmy Roussel ◽  
A.J. Murray ◽  
John Rolley ◽  
D. Barrie Johnson ◽  
L.E. Macaskie
Keyword(s):  
Quantum Dots ◽  
Zinc Sulfide ◽  
Mine Drainage ◽  
Electronic Band ◽  
Light Emitting ◽  
Waste Gas ◽  
Sulfate Reducing ◽  
Relaxation Phase ◽  
Process Waste ◽  
Reducing Bacteria

Dissimilatory reduction of sulfate, mediated by various species of sulfate-reducing bacteria (SRB), can be used to remediate acid mine drainage (AMD). Hydrogen sulfide (H2S/HS-) generated by SRB can be used to remove toxic metals from AMD as sulfide biominerals. For this, SRB are usually housed in separate reactor vessels to those where metal sulfides are generated; H2S is delivered to AMD-containing vessels in solution or as a gas. This allows more controlled separation of metal precipitation and facilitates enhanced process control. Industries such as optoelectronics use quantum dots (QDs) in, for example, light emitting diodes and solar photovoltaics. QDs are nanocrystals with semiconductor bands that allow them to absorb light and re-emit it intensely at specific wavelength couples. Small nanoparticles have the possibility to get electrons shifted to a higher energy and then emit light during the relaxation phase. The QD elemental composition and the presence of doping agent determines its electronic band gaps and can be used to tune the QD to desired emission wavelengths. Traditional QD production at scale is costly and/or complex. Waste H2S gas from growth of SRB has been used to make zinc sulfide QDs which are indistinguishable from ’classically’ prepared counterparts with respect to their physical and optical properties. Clean recycling of minewater bioremediation process waste gas into high value QD product is described.

On the stability of alkali metal promoters in Co mixed oxides during direct NO catalytic decomposition

2017 ◽  
Vol 428 ◽  
pp. 33-40 ◽  
Author(s):  
K. Pacultová ◽  
V. Draštíková ◽  
Ž. Chromčáková ◽  
T. Bílková ◽  
K. Mamulová Kutláková ◽  
...  
Keyword(s):  
Alkali Metal ◽  
Mixed Oxides ◽  
Catalytic Decomposition ◽  
The Stability

scholarly journals Catalytic decomposition of methane on Ni-containing catalysts prepared by heterophase sol-gel method

2021 ◽  
Vol 340 ◽  
pp. 01011
Author(s):  
Maxim Popov ◽  
Vladimir Maximov ◽  
Viktor Kogan
Keyword(s):  
Thermal Conductivity ◽  
Thermal Stability ◽  
High Activity ◽  
High Stability ◽  
Low Cost ◽  
Sol Gel ◽  
Catalytic Decomposition ◽  
Gel Method ◽  
Sol Gel Method ◽  
Decomposition Of Methane

The most promising catalysts for the catalytic decomposition of methane are nickel-containing systems, since nickel has high activity, thermal stability, thermal conductivity, and relatively low cost. In this work, catalysts were prepared by the heterophase sol-gel method and investigated using catalytic equipment. The catalysts showed high stability and lifetime during the catalytic decomposition of methane at temperatures ranging from 535 to 675°C.

Study on N2O Catalytic Decomposition over Mixed Oxides Derived from Co-Mg/Al Hydrotalcite-like Compounds

2007 ◽  
Vol 23 (02) ◽  
pp. 162-168 ◽  
Author(s):  
TAO Yan-Xin ◽  
◽  
◽  
YU Jun-Jie ◽  
LIU Chang-Chun ◽  
...  
Keyword(s):  
Mixed Oxides ◽  
Catalytic Decomposition

Low-Temperature Catalytic Combustion of VOCs over MnOx–ZnO Mixed Oxides Supported on Cordierite Ceramic

2014 ◽  
Vol 989-994 ◽  
pp. 671-675
Author(s):  
Qiong Huang ◽  
Ying Wen Chen ◽  
Shu Bao Shen ◽  
Min Dong Chen
Keyword(s):  
Low Temperature ◽  
High Activity ◽  
Calcination Temperature ◽  
Catalytic Combustion ◽  
Mixed Oxides ◽  
Molar Ratio ◽  
Complete Combustion ◽  
Preparation Conditions ◽  
Cordierite Ceramic ◽  
And Performance

Catalytic combustion of VOCs was investigated over Mn–Zn mixed oxides supported on cordierite ceramic (Cord) and over the promoted Mn-Zn oxides with γ–Al2O3 coating. The properties and performance were characterized by using the XRD, SEM, BET, and TPD techniques. Mn-Zn oxides catalysts with different kinds of γ–Al2O3 sol coating were found to possess a high activity, and the Mn–Zn/γ–Al2O3/Cord (Mn/Zn=2) was identified as the most active that the temperature of complete combustion of toluene was 250°C. Effects of variation of preparation conditions, including molar ratio of Mn and Zn, loading, calcination temperature and different kinds of γ–Al2O3 dipping were investigated.

Catalytic Decomposition of Dinitrogen Oxide over Perovskite-Related Mixed Oxides

1995 ◽  
Vol 68 (4) ◽  
pp. 1226-1231 ◽  
Author(s):  
Jie Wang ◽  
Hiroyuki Yasuda ◽  
Kei Inumaru ◽  
Makoto Misono
Keyword(s):  
Mixed Oxides ◽  
Catalytic Decomposition ◽  
Dinitrogen Oxide

scholarly journals A Review on the Catalytic Decomposition of NO by Perovskite-Type Oxides

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 622
Author(s):  
Qiuwan Shen ◽  
Shuangshuang Dong ◽  
Shian Li ◽  
Guogang Yang ◽  
Xinxiang Pan
Keyword(s):  
Mixed Oxides ◽  
Low Cost ◽  
Influence Factors ◽  
Catalytic Decomposition ◽  
Catalytic Performance ◽  
No Decomposition ◽  
Reaction Conditions ◽  
A Site ◽  
Perovskite Type ◽  
Decomposition Of No

Direct catalytic decomposition of NO has the advantages of being a simple process, producing no secondary pollution, and being good for the economy, which has attracted extensive research in recent years. Perovskite-type mixed oxides, with an ABO3 or A2BO4 structure, are promising materials as catalysts for NO decomposition due to their low cost, high thermal stability, and, of course, their good catalytic performances. In this review, the influence factors, such as A-site substitution, B-site substitution and reaction conditions on the catalytic performance of catalysts have been expounded. The reaction mechanisms of direct NO decomposition are also discussed. Finally, major conclusions are drawn and some research challenges are highlighted.

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