عنوان مقاله [English]
In this study, perovskite Ba0.5Sr0.5Co0.8Fe0.2O3−δ and SrCo0.8Fe0.2O3−δ were synthesized by EDTA and citrate complexing methods. The microstructural studies were carried out using X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) to investigate the crystal structure and also structural stability. Oxygen permeation through BSCF and SCF membranes were measured at elevated temperatures (700oC to 950oC). XRD results showed that both specimens possess perovskite and cubic structure. A relatively high permeation value (2 cc/min.cm2 at 950oC) were reported for both specimens. The results indicated that oxygen permeation of BSCF is higher than that of SCF through a wide range of temperature. Also, the effect of upstream partial pressure of oxygen (0-1 atm) on oxygen flux was studied at various temperatures. The increase in oxygen partial pressure significantly increases the oxygen flux which suggests that these membranes may be used for industrial application. Activation energy results revealed that permeation of SCF membrane at low temperatures is more sensitive to temperature than BSCF which is contrary to observations at high temperatures. It was concluded that Oxygen permeation flux is controlled by both surface exchange kinetics and bulk diffusion. XRD patterns after (adsorption-desorption treatment) indicated that BSCF has a more stable structure at high- temperatures than SCF and also possesses lower oxygen partial pressures.
 Wang H., Wang R., Liang D.T. & Yang W., “Experimental and simulation study on a catalyst packed tubular dense membrane reactor for partial oxidation of methane to syngas”, J. Membrane Sci, Vol. 55, pp. 2617-2625, 2000.
 Hendriksen P.V., Larsen P.H., Mogensen M., Poulsen F.W. & Wiik K., “Prospects and problems of dense oxygen permeable membranes”, Catal. Today, Vol. 56, pp. 283-295, 2000.
 Li S., Jin W., Huang P., Xu N., Shi J., Hu M.Z., E. Payzant A. & Ma Y.H., “Perovskite-Related ZrO2-Doped SrCo0.4Fe0.6O3-δ membrane for oxygen permeation”, AIChE J., Vol. 45, No. 2, pp. 276-284, 1999.
 Shao Z., Dong H., Xiong G., Cong Y. & Yang W., “Performance of a mixed-conducting ceramic membrane reactor with high oxygen permeability for methane conversion”, J. Membrane Sci, Vol. 183, pp. 181-192, 2001.
 Li S., Jin W., Huang P., Xu N. & Shi J., “Comparison of oxygen permeability and stability of perovskite type La0.2A0.8Co0.2Fe0.8O3-δ (A= Sr, Ba, Ca) Membranes”, Ind. Eng. Chem. Res.,Vol 38, pp. 2963-2972, 1999.
 Yaremchenko A.A., Kharton V.V., Shaula A.L., Patrakeev M.V. & Marques F.M.B., “Transport properties and thermal expansion of perovskite-like La0.3Sr0.7Fe(Al,Cr)O3−
 Tsai Ch.Y., A Dixon. G., Moser W.R. & Ma Y.H., “Dense perovskite membrane reactors for partial oxidation of methane to syngas, AIChE J.”, Vol. 43, pp. 2741-2750, 1997.
 Sammells A.F., Schwartz M., Mackey R.A., Barton T.F. & Peterson D.R., “Catalytic membrane reactors for spontaneous synthesis gas production”, Catal. Today, Vol. 56, pp. 325-328, 2000.
 Wang H., Wang R., Liang D.T. & Yang W., “Experimental and simulation study on a catalyst packed tubular dense membrane reactor for partial oxidation of methane to syngas”, J. Membrane Sci., Vol. 55, pp. 2617-2625, 2000.
 Steele B.C.H., “Ceramic ion conducting membranes”, Curr. Op. Solid State Mater. Sci., Vol. 1, pp. 684-691, 1996.
 Teraoka Y., Zhang H.M., Furukawa S. & Yamazoe N., “Oxygen permeation through perovskite-type oxides”, Chem. Lett., Vol. 167, pp. 1743–1746, 1985 .
 Teraoka Y., Nobunaga T. & Yamazoe N., “Effect of cation substitution on the oxygen semi permeability of perovskite-type oxides”, Chem. Lett., Vol. 195, pp. 503–506, 1988.
 Teraoka Y., Nobunaga T., Okamoto K., Miura N. & Yamazoe N., “Influence of constituent metal cations in substituted LaCoO3 on mixed conductivity and oxygen permeability”, Solid State Ionics, Vol. 48, pp. 207–212, 1991.
 Yang D., Lu H., Song H., Guo Y. & Hu X., “Experimental study of oxygen diffusion and permeation through YBa2Cu3O7−x membranes”, J. Membrane. Sci., Vol. 233, pp. 45-50, 2004
 Zhu Z.L., Guo L.J., Wang H.Y., Yang D.L., Li X.J. & Hu X., “Potential application of superconducting material YBa2Cu3O7-x as oxygen resisdence sensors”, Int. J. Mod. Phys. B, Vol. 19, pp. 3923-3932, 2005.
 Schwartz M., White J.H. & Sammells A.F., Solid state oxygen anion and electron mediating membrane and catalytic membrane reactors containing them, U.S. Patent, 6214757, 2001.
 Kharton V.V., Yaremchenko A.A., Patrakeev M.V., Naumovich E.N. & Marques F.M.B., “Thermal and chemical induced expansion of La0.3Sr0.7(Fe,Ga)O3−δ ceramics”,J. Eur. Ceram. Soc., Vol. 23, pp. 1417–1426, 2003.
 Mazanec T. J., Electropox gas reforming , the First International Symposium on Ceramic Membranes,Pennington, NJ, (PV95-24), pp. 16–28, 1997.
 Hayashi H., Inaba H., Matsuyama M., Lan N.G., Dokiya M. & Tagawa H., “Structural consideration on the ionic
conductivity of perovskite-type oxides”,Solid State Ionics, Vol. 122, pp.1-15, 1999.
 Shao Z.P., Xiong G.X., Cong Y. Dong, H., Tong J. H, Yang W.S., “Investigation on the permeation behavior and stability of a Ba0.5Sr0.5Co0.8Fe0.2O3−
δ oxygen membrane”, J. Membrane Sci., Vol. 172, pp.177-188, 2000.
 Wang H., Wang R., Liang D.T. & Yang W., “Experimental and modeling studies on Ba0.5Sr0.5Co0.8Fe0.2O3−
δ (BSCF) tubular membranes for air separation”, J. Membrane Sci., Vol. 243, pp. 405-415, 2004.
 Zeng P., Chen Z., Zhou W., Gu H., Shao Z. & Liu S., “Re-evaluation of Ba0.5Sr0.5Co0.8Fe0.2O3−
δ perovskite as oxygen semi-permeable membrane”, J. Membrane Sci., Vol. 291, pp. 148–156, 2007.
 Kruidhof H., Bouwmeester H.J.M., Doorn R.H.E. & Burggraaf A.J., “Influence of order-disorder transitions on oxygen permeability through selected nonstoichiometric perovskite type oxides”, Solid State Ionics, Vol. 63-65, pp. 816-822, 1993.
 Bouwmeester H.J.M. Kruidhof H. & Burggraaf A.J., Importance of the surface exchange kinetics as rate limiting step in oxygen permeation through mixed-conducting oxides, Presented at Ninth International Conference on Solid State Ionics, Netherlands, 1993.
 Dou S., Masson C.R. & Pacey P.D., “Mechanism of oxygen permeation through lime-stabilized zirconia”, J. Electrochem. Soc., Vol. 132, pp.1843-1849, 1985.
 Itoh N., Kato T., Uchida K. & Haraya K., “Preparation of pore free disk of La1-xSrxCoO3 mixed conductor and its oxygen permeability”, J. Membrane Sci., Vol. 92, pp. 239-246, 1994.
 Kim S., Yang Y.L., Christoffersen R. & Jacobson A.J., “Determination of oxygen permeation kinetics in a ceramic membrane based on the composition SrFeCo0.5O3−
δ”, Solid State Ionics, Vol. 109, pp. 187-196, 1998.
 Kim S., Yang Y.L., Jacobson A.J. & Abeles B., “Diffusion and surface exchange coefficients in mixed ionic electronic conducting oxides from the pressure dependence of oxygen permeation”, Solid State Ionics, Vol. 106, pp. 189-195, 1998.
 Tong J., Yang W., Cai R., Zhu B. & Lin L., “Novel and ideal zirconium-based dense membrane reactors for partial oxidation of methane to syngas”, Catal. Lett., Vol. 78, No. 1-4, pp. 129-137, 2002.
δ for oxygen permeating membrane”, J. Membrane Sci., Vol. 306, pp. 318-328, 2007.