Hydrogen Purification using Ultra-Thin Palladium Films Supported on Porous Anodic Alumina Membranes

2007 ◽  
Vol 1023 ◽  
Author(s):  
Alexander Kirchner ◽  
Ian W.M. Brown ◽  
Mark E. Bowden ◽  
Tim Kemmitt

AbstractNanostructured anodic alumina membranes have been utilized as high-temperature stable supports for 150 nm thick continuous palladium films. The palladium has been deposited by vacuum evaporation onto the rotating substrate. The thermal stability of the resulting compound membranes has been demonstrated for temperatures up to 700ºC under a reducing atmosphere. Hydrogen permeation has been measured up to 280ºC, where the permeability has a value of 2.5·10-7 mol m-2 s-1 Pa-1. At the same time the selectivity factor over carbon dioxide is at least 33.

2008 ◽  
Vol 111 (2-3) ◽  
pp. 542-547 ◽  
Author(s):  
L. Fernández-Romero ◽  
J.M. Montero-Moreno ◽  
E. Pellicer ◽  
F. Peiró ◽  
A. Cornet ◽  
...  

2013 ◽  
Vol 48 (6) ◽  
pp. 348-354 ◽  
Author(s):  
Danli Wang ◽  
Yongfeng Ruan ◽  
Lingcui Zhang ◽  
Wei Zhu ◽  
Pengfei Wang

2018 ◽  
Vol 19 (12) ◽  
pp. 3723 ◽  
Author(s):  
Shaoyun Chen ◽  
Min Xiao ◽  
Luyi Sun ◽  
Yuezhong Meng

The terpolymerization of carbon dioxide (CO2), propylene oxide (PO), and cyclohexene oxide (CHO) were performed by both random polymerization and block polymerization to synthesize the random poly (propylene cyclohexene carbonate) (PPCHC), di-block polymers of poly (propylene carbonate–cyclohexyl carbonate) (PPC-PCHC), and tri-block polymers of poly (cyclohexyl carbonate–propylene carbonate–cyclohexyl carbonate) (PCHC-PPC-PCHC). The kinetics of the thermal degradation of the terpolymers was investigated by the multiple heating rate method (Kissinger-Akahira-Sunose (KAS) method), the single heating rate method (Coats-Redfern method), and the Isoconversional kinetic analysis method proposed by Vyazovkin with the data from thermogravimetric analysis under dynamic conditions. The values of ln k vs. T−1 for the thermal decomposition of four polymers demonstrate the thermal stability of PPC and PPC-PCHC are poorer than PPCHC and PCHC-PPC-PCHC. In addition, for PPCHC and PCHC-PPC-PCHC, there is an intersection between the two rate constant lines, which means that, for thermal stability of PPCHC, it is more stable than PCHC-PPC-PCHC at the temperature less than 309 °C and less stable when the decomposed temperature is more than 309 °C. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and thermogravimetric analysis/infrared spectrometry (TG/FTIR) techniques were applied to investigate the thermal degradation behavior of the polymers. The results showed that unzipping was the main degradation mechanism of all polymers so the final pyrolysates were cyclic propylene carbonate and cyclic cyclohexene carbonate. For the block copolymers, the main chain scission reaction first occurs at PC-PC linkages initiating an unzipping reaction of PPC chain and then, at CHC–CHC linkages, initiating an unzipping reaction of the PCHC chain. That is why the T−5% of di-block and tri-block polymers were not much higher than that of PPC while two maximum decomposition temperatures were observed for both the block copolymer and the second one were much higher than that of PPC. For PPCHC, the random arranged bulky cyclohexane groups in the polymer chain can effectively suppress the backbiting process and retard the unzipping reaction. Thus, it exhibited much higher T−5% than that of PPC and block copolymers.


2009 ◽  
Vol 98 (4) ◽  
pp. 745-749 ◽  
Author(s):  
Xue Hua Wang ◽  
Cheng Yong Li ◽  
Gui Chen ◽  
Lei He ◽  
Hong Cao

2009 ◽  
Vol 105 (10) ◽  
pp. 103504 ◽  
Author(s):  
C.-S. Tu ◽  
R. R. Chien ◽  
V. H. Schmidt ◽  
S.-C. Lee ◽  
C.-C. Huang ◽  
...  

Open Physics ◽  
2010 ◽  
Vol 8 (3) ◽  
Author(s):  
Viorel Badescu

AbstractThe existence of life on a free-floating planet is conditioned by the existence of an optically thick atmosphere. This may ensure the long-term thermal stability of a (liquid) solvent on the surface of that body. Requirements to be fulfilled by a hypothetic gas constituent of a free-floating planet atmosphere are studied. The four gases analyzed here (nitrogen, carbon dioxide, methane and ethane) are candidates. They may induce a higher opacity than molecular hydrogen, which has been considered in previous research. The paper deals with preparation of tables of Rosseland mean opacity values. Selection of the ranges of temperature and pressure is guided by life existence considerations. The range of temperatures involved (50 to 650 K) is lower than usually found in the literature. The tables may be useful for studies related to free-floating planets, where the usage of absorption opacity is a straightforward way to compute the energy flux in the atmosphere. Also, the results are useful in all cases where radiation is transferred through dense layers of the gases considered in this paper.


1995 ◽  
Vol 129 (1) ◽  
pp. 69-82 ◽  
Author(s):  
V. Perrichon ◽  
A. Laachir ◽  
S. Abouarnadasse ◽  
O. Touret ◽  
G. Blanchard

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