Oxygen-permeable membrane

One example of membrane reactors is oxidation, in which oxygen from one phase diffuses from one side of an oxygen-permeable membrane to react with a fuel on the other side of the membrane. This avoids a high concentration of O2 on the fuel side, which would be flammable. A catalyst on the fuel side of the membrane oxidizes the fuel to partial oxidation products. One important process using a membrane reactor is the reaction to oxidize methane to form syngas,... 

The resulting electric current is proportional to the oxygen flux to the cathode through the oxygen-permeable membrane that separates the electrode from a culture medium. 

A major advance in the performance of amperometric oxygen sensors has been achieved by placing both the cathode and the anode behind the oxygen-permeable membrane (Fig. 7.4). This sensor is known as the Clark oxygen electrode. 

The calibration curves of the sensor IV, which was prepared with a PMSP membrane as an oxygen permeable membrane and an acetyl celulose(AC) membrane as a glucose semipermeable membrane, were shown in Figure 8. This AC membrane was cast by Manjikian s method and treated at a curing temperature of 85°C. The sensor ]V indicated a linear response up to 500 mg/dl of glucose concentration, even under 5 % of oxygen tension, and the output currents were hardly affected by oxygen tension. 

An alternative approach places the Pt electrodes directly on a flexible polymer carrier [80]. Eh Lilly developed a three-electrode transducing system based on a polyimide carrier with electroadsorbed enzyme and a highly oxygen-permeable membrane covering the sensor. Such a system was tested in vivo and published results seem encouraging although the company cancelled the project. 

Fig. 1. Different types of bioreactors for plant cell, tissue and organs. (A) mechanically-agitated bioreactors, a aeration-agitation, b rotating drum, c spin filter. (B) air-driven bioreactors, a bubble column, b draft tube, c external loop, (C) non-agitated bioreactors, a gaseous phase (mist), b oxygen permeable membrane aerator, c surface aeration, (D) light emitting draft tube...

Oxide ion conductors have been extensively investigated for their applications in fuel cells, oxygen sensors, oxygen pumps, and oxygen permeable membranes [81-108], The ion conduction effect was discovered more than a century ago by Nernst in zirconia products [83,84], To use zirconia, it... 

In the cathode of an SOFC, oxygen, supplied typically as air to one side of the oxygen permeable membrane, is reduced by the cathode to oxygen ions via the following overall half-cell reaction (see Figure 8.7) ... 

The oxygen anions created are selectively transferred through the oxygen-permeable membrane to the anode, where they experience a similar half-cell reaction with a gaseous fuel, either H2, syngas (CO + Hj), or a hydrocarbon, to produce H20 and C02. For example, if the fuel is CH4, the oxidation reaction in the anode is given by... 

The concentration of dissolved oxygen is determined by two electrodes immersed in an electrolyte contained in a vessel with an oxygen-permeable membrane wall. The cell is placed in a container through which the measured water flows. Oxygen diffuses into the cell in direct proportion to its concentration in the measured water. The diffused oxygen is consumed... 

HYDROGEN PRODUCTION FROM HYDROCARBONS BY USING OXYGEN PERMEABLE MEMBRANES... 

In this paper, the development of the planar-type MPOX reformer based on the oxygen permeable membrane of (Ceo.85Smo.i5)02-15vol%MnFe204 and its reforming properties will be reviewed. In addition, the durability of the oxygen permeable membrane, which is one of the most important characteristics in practical use, will be examined. 

PM Hydrogen Production from Hydrocarbons by using Oxygen Permeable Membranes ... 

Wang H, Cong Y, and Yang W. Partial oxidation of ethane to syngas in an oxygen-permeable membrane reactor. J. Membr. Sci. 2002 209 143-152. 

The third sub-configuration (C) uses oxygen permeable membranes instead of hydrogen permeable membranes. Again air is used as an oxygen source in... 

The separator employed in the sealed cells is not a gas barrier, but rather an oxygen permeable membrane (such as nonwoven nylon, polypropylene, etc.). 

In conjunction with membrane-based blood oxygenators for example, microchannels offer improved gas exchange efficiency and reduce the volume of blood required for initial priming. A device developed by Himg et al. [281] involves a stack of 16 plate units incorporating 110 pm deep by 230 pm wide microchannels sandwiched with oxygen permeable membranes (Fig. 7.22). Experimental results not only show improved gas exchange efficiency over both macrochannels and theoretical predictions, but also a reduction in apparent blood viscosity. 

In 1954 Leland Clark demonstrated that a platinum cathode would measure the oxygen concentration of blood when it and a reference electrode were covered by an oxygen permeable membrane. Later in that same year Stow and Severinghaus showed that carbon dioxide could be estimated in blood with a glass electrode fitted with a gas permeable membrane. In the seventies the Huchs demonstrated that mechanical adaptations of these devices could be utilized to provide transcutaneous (non-invasive) measurement of arterial blood gas concentration if the skin area surrounding the sensor was heated to 44 - 45°C. 

Wang H, Cong Y, Yang W. Oxygen permeation study in a tubular BaQ5SrQ5CoQ8FeQ203 g oxygen permeable membrane. JMembrSci 2002 210 259-271. 

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