Conductors membranes

The potentiometric determination of bromide anions with ion-selective electrodes is possible with commercial electrodes that are commonly based on solid Ag2S—AgBr ion conductor membranes [148-150]. Recently, a novel liquid film sensor has been proposed by Ganjali etal. [151] Determination of bromide was reliable without significant interference from common ions such as chloride and iodide, and was reported down to a micromolar level. The electroactive species in the liquid membrane... 

Sensing mechanism of the modified sensor. The sensing mechanism in this modified sensor should be essentially the same as that of the unmodified one. It is noteworthy that a stationary short circuit current was obtained in spite of such sensor construction that the counter electrode was covered with Epoxy resin. Since the sensing electrode is placed in the same situation as the unmodified sensor, this fact indicates that the cathodic reaction is allowed to take place stationarily at the counter electrode. The proton conductor membrane is as thin as 0.2 mm, so that the reactant 02 and the produced H20 will permeate the membrane as shown in Figure 11. A part of H2 will naturally also permeate through the membrane, but the transfered H2 will be consumed by the reaction with 02 electro-chemically or catalytically at the counter electrode. 

The use of a mixed oxygen ion-electronic conductor membrane for oxygen separation with direct reforming of methane, followed by the use of a mixed protonic-electronic membrane conductor for hydrogen extraction has also been proposed in the literature [34]. The products are thus pure hydrogen and synthesis gas with reduced hydrogen content, the latter suitable, for example, in the Fish-er-Tropsch synthesis of methanol [34]. 

Solid Ionic Conductors. Membranes that provide a medium for the transport of hthium ions or protons... 

R.M. Thorogood, R. Srinivasan, T.F. Yee and M.P. Drake, Composite mixed conductor membranes for producing oxygen US Patent 5,240,480,1993. 

M. Dum61ie, G. Nowogrocki and J.C. Boivin, Ionic conductor membrane for oxygen separation. Solid State Ionics, 28-30 (1988) 524-528. 

Burgmayer P and Murray R W 1984 Ion Gate Electrodes. Polypyrrole as a switchable ion conductor membrane J. Phys. Chem. 88 2515-21 Otero T F and de Larreta E 1988 Conductivity and capacity of polythiophene films impedance study J. Electroanal. Chem. 244 311-18 Sunde S, Hagen G and Odegird R 1993 Impedance analysis of the electrochemical doping of poly(3-methyl-thiophene) from aqueous nitrate solutions J. Electroanal. Chem. 345 59-82 Zaborsky O R 1973 Immobilized Enzymes (Cleveland, OH Chemical Rubber Company) (see especially pp 69,87)... 

Yee TF, Srinivasan R, Thorogood RM. Oxygen production by staged mixed conductor membranes. U.S. Patent 5,447,555, 5 Sep 1995. 

Thorogood RM, Srinivasan R, Yee TF, Drake MR Composite mixed-conductor membranes for producing oxygen. U.S. Patent 5,240,480, 31 Aug 1993. 

Burgmayer, P., and R.W. Murray. 1984. Ion gate—polypyrrole as a switchable ion conductor membrane. / Phys Chem 88 2515. 

Fontaine, M., Norby, T., Earring, Y., etai (2008). Oxygen and Hydrogen Separation Membranes Based on Dense Ceramic Conductors, Membrane Science and Technology, 13, pp. 401 58. 

Table 10.1 summarizes the characteristics of common ISEs and a number of new sensors in this field. We have not included in this table the liquid or polymer membrane-based electrodes which are selective, but rather fragile (for more details on such membranes see References 58,59). ISEs of the first kind are not very numerous, e.g., F -ISE (monocrystalhne membrane based on LaFj), Ag" -ISE (silver salts), or Na" -ISE (Na alumino-silicate glass or polyciystalline NASICON [Na super ionic conductor] membranes). Most of the ISEs are of the second kind and are based on insoluble silver salts for example, halide ISEs (CE, Br, I"), Cd ", Pb ", Cu ", etc. Such ISEs use mixtures of insoluble salts based on silver sulfide or silver selenide. Recently, Vlasov etal. and Neshkova have proposed several glasses sensitive to transition metals. Typical ISE devices are shown in Figure 10.5. Thin-layer chemical sensors based on chalcogenide glasses have also been developed. ... 

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