Search / Korean Journal of Chemical Engineering
HWAHAK KONGHAK,
Vol.38, No.2, 142-148, 2000
Glassy Carbon 섬유 다발체 전극에서 Np 산화가 조절을 통한 Np의 TBP에 대한 추출증진 연구
A Study on Enhancement of Neptunium Extraction by TBP through the Electrochemical Adjustment of Neptunium Valance by Using a Glassy Carbon Filber Column Electrode System
본 연구에서는 질산농도 0.5-5.5M 범위에서 Np의 상태가 분석을 흡광도, TBP(tri-butyl phophate)에 의한 용매추출, 전기화학적인 방법으로 수행하였고 또한 아질산의 존재에 따른 Np의 상태가 변화에 대한 영향을 고찰하였다. 그리고 GC 섬유 다발체 전극을 이용하여 Np 산화가 조절을 통한 Np의 30% vol. TBP에 대한 추출 증진 연구를 수행하였다. 본 연구에서 사용된 Np 용액에는 Np(IV)없이 Np(V)와 Np(VI)만이 존재하였고, 질산농도 0.5-5.5 M에서 Np(V)의 조성은 32-19%이었다. Np 용액중에 공존하는 Np(V)를 Np(VI)로 전해적 방법으로 산화시킨 후 TBP에 의한 Np 추출의 분배계수는 5개정도 증가하였다. 10-5M 이하의 아질산은 Np(V)의 산화반응을 촉진시켜 주는 촉매 역할을 하고 10-3 M 이상의 아질산은 Np(VI)에 대해 환원제로 작용함을 확인하였다.
The Np valance state in nitric acid and the effect of nitrous acid on the Np valance composition were studied through the ways of absorbance by spectrophotometer, extraction by TBP, and electrochemistry. Enhancement of Np extraction to 30 vol% TBP was carried out through adjustment of Np valance state by using a glassy carbon fiber column electrode system. The Np solution used in this work consisted of only Np(V) and Np(VI) without Np(IV). The composition of Np(V) in the range of 0.5-5.5 M nitric acid was 32-19%. The electrolytic oxidation of Np(V) coexisting with Np(V) in the solution enhanced Np extraction by 30 vol% TBP about five times more than that without the electrolytic oxidation. The facts were confirmed that the nitrous acid of less than about 10-5 M acted as a catalyst to accelerate the chemical oxidation reaction of Np(V) to Np(VI) and the nitrous acid of more than 10-3 M reduced Np(VI) to Np(V).
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