Time-dependent radiolytic yields at room temperature and temperature-dependent absorption spectra of the solvated electrons in polyols

The molar extinction coefficients at the absorption maximum of the solvated electron spectrum have been evaluated to be 900,970,and 1000 mol^(-1).m^2 for 1,2-ethanediol (12ED),1,2-propanediol (12PD),and 1,3-propanediol (13PD),respectively.These values are two-third or three-fourth of the value usually reported in the published report. Picosecond pulse radiolysis studies have aided in depicting the radiolytic yield of the solvated electron in these sol- vents as a function of time from picosecond to microsecond.The radiolytic yield in these viscous solvents is found to be strongly different from that of the water solution.The temperature dependent absorption spectra of the solvated electron in 12ED,12PD,and 13PD have been also investigated.In all the three solvents,the optical spectra shift to the red with increasing temperature.While the shape of the spectra does not change in 13PD,a widening on the blue side of the absorption band is observed in 12ED and 12PD at elevated temperatures.

Electrochemical properties of gadolinium on liquid gallium electrode in LiCl-KCl eutectic

This work presents the electrochemical properties of gadolinium(Gd), a significant rare earth element in spent nuclear fuel(SNF), in the LiCl-KCl eutectic. To explore thermodynamic properties of Gd at the liquid gallium(Ga) electrode, experiments were performed both on the inert tungsten(W) and liquid gallium(Ga) electrode at different temperatures in a range from 723 to 823 K, which show that the Gd metal can be oxidized to Gd(Ⅲ) by exchanging of 3 electrons. Electrochemical techniques including cyclic voltammetry(CV), open circuit potential(OCP), potentiostatic electrolysis and galvanostatic electrolysis were utilized to detect the electrochemical behavior and evaluate standard apparent potential of the Gd(Ⅲ)/Gd couple,and E(Gd(Ⅲ)/Gd)*=-3.456 + 6.2×10-4T(±0.046)( vs Cl2/Cl-) is obtained.In addition, electromotive force(EMF) and coulometric titration were employed to calculate the activity and activity coefficient of Gd in metal Ga. After calculation, the activity is 1.791×10-15at 723 K and function of activity coefficient and temperature is lgγ = 3.485-10927/T(±0.0875).

An effective process for the separation of U(Ⅵ),Th(Ⅳ)from rare earth elements by using ionic liquid Cyphos IL 104

Separation and recovery of U(Ⅵ)and Th(Ⅳ)from rare earth minerals is a very challenging work in rare earth industrial production.In the present study,a homemade membrane emulsification circulation(MEC)extractor was used to separate U(Ⅵ)and Th(Ⅳ)from rare earth elements by using Cyphos IL 104 as an extractant.Batch experiments were carried out using a constant temperature oscillator to investigate the extraction parameters of the single element and the results indicated that Cyphos IL 104could reach the extraction equilibrium within 30 min for all the three elements,i.e.,U(Ⅵ),Th(Ⅳ),and Eu(Ⅲ).Besides,the MEC extractor possessed a strong phase separation ability.The extraction efficiencies of U(Ⅵ),Th(Ⅳ),La(Ⅲ),Eu(Ⅲ)and Yb(Ⅲ)increased with the increase of pH.La(Ⅲ),Eu(Ⅲ)and Yb(Ⅲ)were hardly extracted when pH≤1.50,which was beneficial for effectively separating U(Ⅵ)and Th(Ⅳ)from La(Ⅲ),Eu(Ⅲ)and Yb(Ⅲ).In the multi-stages stripping experiments,when the stripping stage number was 3,the effective separation could be achieved by using HCl and H_(2)SO_(4),since the stripping efficiency reached 80.0%and 100.0%for Th(Ⅳ)and U(Ⅵ),respectively.Slope method and FT-IR spectra showed that Cyphos IL 104 reacted with U(Ⅵ)and Th(Ⅳ)by chelation mechanism.The extraction of multi-elements indicated that U(Ⅵ)and Th(Ⅳ)could be well separated from the solution which contains all rare earth elements,and the extraction efficiencies of U(Ⅵ)and Th(Ⅳ)both were close to 100.0%.Based on the above experimental results,a flowchart for efficient separation of U(Ⅵ)and Th(Ⅳ)from rare earth elements was proposed.