Reduction of Trivalent Europium in Molten LiCl-KCl Eutectic Observed by In-Situ Laser Spectroscopic Techniques

Abstract

The in-situ quantification for the reduction of Eu(III) was performed in the LiCl-KCl eutectic at various temperatures by time-resolved laser fluorescence spectroscopy (TRLFS) and UV-Vis absorption spectroscopy. From the results of absorption measurement, Eu(III) virtually underwent complete reduction to Eu(II) under the present experimental conditions, while TRLFS revealed a relatively greater reducing power of Eu(III) in the chloride molten eutectic with decreasing its concentration and increasing temperature. However, it was convincingly identified that fluorescence measurements deliver more reliable quantification, compared with the UV-Vis absorption measurements, showing a mutually hindered overlap of absorption bands of Eu(II) and Eu(III).