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用乙酰丙酮(HAA)-三氯甲烷萃取分离Fe~(3+)和Fe~(2+)已有报道,但在α,α-联吡啶介质中分离效果较差。我们研究了用邻菲啰啉作Fe~(2+)和Fe~(3+)的显色剂,在pH=4的醋酸-醋酸铵缓冲溶液中,用HAA-CHCl_3萃取分离Fe~(3+)和Fe~(2+)效果较好。萃取到有机相中的Fe~(3+)和HAA啰呈黄色络合物,最大吸收波长为445nm,表观摩尔吸光系数为3.5×10~3。水相中的Fe~(2+)-邻菲啰啉呈红色络合物,最大吸收波长为510nm。二种络合物均服从比尔定律,因而可以用光度法连续测定铀工艺溶液中Fe~(2+)和Fe~(3+)的含量。实验结果证明,拟定的分析步骤,操作简便、快速,用于生产实践获得满意的结果。
The extraction of Fe ~ (3+) and Fe ~ (2+) with acetylacetone (HAA) -trichloromethane has been reported, but its separation in α, α-bipyridine is poor. We studied the use of phenanthroline as Fe 2+ and Fe 3+ reagent in the pH = 4 acetic acid-ammonium acetate buffer solution, with HAA-CHCl 3 extraction and separation of Fe 3 (3 +) And Fe ~ (2+) are better. The Fe (3+) and HAA extracted into the organic phase showed a yellow complex with a maximum absorption wavelength of 445 nm and an apparent molar absorptivity of 3.5 × 10 -3. Fe ~ (2 +) - phenanthroline in aqueous phase showed a red complex with a maximum absorption wavelength of 510 nm. Beer’s law is obeyed by the two complexes, so the content of Fe 2+ and Fe 3+ in uranium solution can be determined continuously by photometry. Experimental results show that the proposed analysis steps, easy to operate, fast, used in production practice to obtain satisfactory results.