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我们为了探讨低燃点钒触媒在使用过程中,四价钒和五价的含量对其催化活性的影响规律,需要测定其中四价钒和五价钒的含量。四价钒和五价钒共存时,分别测定不同价态的钒,必须解决它们之间的干忧问题。栲胶脱硫液中测定四价钒的方法,是用8—羟基喹林与四价钒生成络合物,用氯仿萃取这络合物,这样使四价钒与五价钒分离。用容量法测定水相中的五价钒,再测定总钒,总钒和五价钒之差即为四价钒的含量。此方法操作冗长,而且消耗大量的有机溶剂、成本高。根据四价钒、五价钒能分别生成不同颜色的磷钨钒杂多酸的性质,我们试验以生成磷钨钒杂
In order to investigate the influence of tetravalent vanadium and pentavalent vanadium on the catalytic activity of low-vanadium vanadium catalyst, we need to determine the contents of tetravalent vanadium and pentavalent vanadium. When tetravalent vanadium and pentavalent vanadium coexist, the different valences of vanadium should be determined separately, and the problem of dryness and worry between them must be solved. The method for the determination of tetravalent vanadium in the xylene gel desulfurization solution is to generate a complex with 8-hydroxyquinoline and tetravalent vanadium and to extract the complex with chloroform so that the tetravalent vanadium is separated from the pentavalent vanadium. Volumetric determination of pentavalent vanadium in the aqueous phase, and then determine the total vanadium, total vanadium and pentavalent vanadium difference is the content of tetravalent vanadium. This method is cumbersome to operate and consumes large amounts of organic solvents at high cost. According to tetravalent vanadium, pentavalent vanadium can generate different colors of phosphotungstic vanadium heteropoly acid properties, we test to generate phosphotungstic vanadium