Study In Preparation Of Strontiam Cobaltite And Its Catalytic Degradation Of Dyes Effluent

Catalytic oxidation technology in the treatment of dye effluent is an extremely valuable subject, which is of high efficiency, energy saving and non-second contamination.Due to the oxidation states (II, III and IV) of cobalt, a wide range of oxygen stoichiometry, several crystalline formations, and special electron structure, cobaltite salt is the best choice in development of new function-materials. Strontium cobaltite is a promising material for fabrication of dense ceramic membranes for oxygen separation, solid electrolytes, solid oxide fuel cells and electrocatalytic reactors and so on. Strontium cobaltite, however, is hardly used in the environmental protection.In the article, strontium cobaltite powders were synthesized by two ways, chemical co-precipitation (CCP) method and polymerized complex method based on citrate process (PC). And samples obtained were characterized by X-ray diffraction (XRD), thermogravimety (TG-DTA), scan electron microscopy (SEM), transmission electron microscopy (TEM), and so on. Furthermore, samples, as catalysis, were used to degrade simulation dye effluents, such as solutions of Acid Red G, Direct Bordeaux, Direct Red and Methylene Blue.The single-phase, microcrystalline homogeneous SrCoOx powders were synthesized successfully using a easily-controlled method (PC) at a lower temperature (800 ) for a shorter holding time (1Oh) in static air, compared with chemical co-precipitation technique and other methods published. The formation process, the structure and homogeneity of the obtained powders have been investigated by TG-DTA, XRD and SEM measurement. The reflections of the powders obtained were indexed on the space group P63/mmc (194) with lattice parameter a=5.486 ± 0.006 A and c=4.20 ± 0.06 A via analysis using the Rierveld method. The average size of SrCoOx powder by PC method at 800 ℃ for 10h is about 250 nm. SEM exhibits SrCoOx powders were of homogenous in distribution of the size and the shape. X-ray photoelectron spectrum (XPS) shows that, the sample don't contain else element, in which Co is present as Co3+ and the amount of adsorption oxide (68.45%) is more than that of crystal lattice oxide (31.55%).On the other hand, using ultraviolet lamp as irradiator, the decompositionexperiments of water soluble dye acid red G were carried out in the suspension system of SrCoOx. The complete discoloration of acid red G and the destruction of structure of azo, benzene ring and condensed nucleus show a good catalytic oxidation activity of the powder. Moreover, the experiment was done to study the relationships between removal rat and catalysis synthesis temperature, hold-time, usage amount, initial concentration and pH value of Acid red G solution. The conclusion is that, SrCoOx powder by PC method at 800 for 10h shows a good performance.In the end of article, mechanics of Acid Red G decomposition was analyzed by infrared analysis (IR) and ultraviolet-visible light analysis (UV-Vis). In conclusion, main action is not adsorption action, but the multi-reasons cooperation action, including photocatalytic oxidation and mechano-catalytic oxidation.