分光光度法测定银催化剂中微量锰

Determination of Trace Manganese in Silver Catalyst by Spectrophotometry

本文研究了浸渍液和银催化剂中微量锰元素的分析方法。银催化剂样品上含有银和有机物对测定有干扰,通过焙烧可消除催化剂中残留的有机物,并用硫酸溶样消除银离子的干扰,最后用高碘酸钾做氧化剂将样品中的各价锰全部氧化为+7价锰显色后进行比色分析。研究结果表明,在3%~5%的H2SO4介质中,高碘酸钾的加入量为5 mg·mL^(-1),加热保温,可实现低价态锰的快速转化,显色稳定。在波长为530 nm处,可以准确测定样品中的锰含量。方法的摩尔吸光系数为2.5×10^(3),在0~120μg·mL^(-1)符合比耳定律,回收率在96.5%~98.5%之间。

In this study, an analysis method of trace manganese in impregnating solution and silver catalyst was studied. Silver catalyst samples contained silver and organic matter, which interfered with the measurement. Roasting could eliminate the residual organic matter in the catalysts. The sample dissolution with sulfuric acid could eliminate the interference of silver ions. Potassium periodate was used as the oxidant to oxidize all manganese in the sample to +7 valence, and colorimetric analysis was performed after color development. The test results found that in the 3 %~5 % H2 SO4 medium, the addition amount of potassium periodate was 5 mg·ml^(-1), heating could realize the rapid conversion of low-valence manganese and stable color development. At the wavelength of 530 nm, the manganese content in the sample could be accurately determined. The molar absorption coefficient of the method was 2.5×10^(3), Beer’s law was in accordance with the range of 0~120 μg·ml^(-1), and the recovery rate was between 96.5 % and 98.5 %.