The Study On The Microwave Assistant Synthesis And Structure Of The Synthetic Perovskite Sorbents

The emission of CO2into the atmosphere has been reported to account for half ofthe greenhouse effect that causes global warming. Oxyfuel combustion is a promisingtechnology which simplifies the flue-gas treatment and has the potential for composing azero CO2emission process. Nevertheless, reducing the cost of oxygen production is akey to make the oxyfuel combustion power plant a viable future option when carbondioxide capture becomes a necessity. Mixed electronic and ionic conducting perovskiteshave a promising future in the use of sorbents for air separation at high temperature. Anew method which used a perovskite ceramic sorbent to produce an O2-enriched CO2stream is proposed.The microwave irradiation has been shown to provide a economical,novel and rapidmethod of preparing many important materials. Microwave processing is a self-heatingprocess that occurs through the absorption of electromagnetic energy. Since themicrowave energy is directly absorbed by the sample, uniform and rapid heating can beachieved within a short period of time. A series of Ba_xSr_1-xCo_yFe_1-yO_3-δperovskites,having important applications, have been successfully synthesized by two differentmethods, namely microwave assistant-citrate and citrate-EDTA complexing method. TheX-ray diffraction （XRD） was used to characterize the phase homogeneity and the particlemorphology was observed by Environment scanning electron microscope （SEM）.Study of different preparation methods on the perovskite-type oxide oxygen releaseperformance has the following results. XRD analysis confirms that all samples preparedin both methods are of perovskite-type structure. The samples synthetized by microwavemethod have smaller particle size. SEM micrographs suggest that The samplessynthetized by microwave method have a porous structure and the samples synthetizedby citrate-EDTA carry a dense structure; the particle size is much smaller than that synthetized by cirate-EDTA complexing method. As to the oxygen desorptionperformance, both methods have a good results. The samples synthetized bycitrate-EDTA complexing method have a good cycling performance than the samplessynthetized by microwave method.GSAS （General Structure and Analysis Sysem）software was retained XRDRietveld refinement. Crystal structure was obtained. The results obtained concerningcells parameters and oxygen fractions. The results showed that the samples synthetizedby microwave method has the smaller cells parameters and with the time of microwaveirritation increasing the cells parameters were decreasing. And to the oxygen fractions,the samples synthetized by citrate-EDTA complexing method has a bigger occupation.The occupation of oxygen atom is increasing with the increase of the microwaveirritation time.