镧在离子液体MPPiNTf2中的电沉积研究

Electrodeposition of Lanthanum in the Room Temperature Ionic Liquid MPPiNTf2

摘要:

为了用室温离子液体替代氯化物高温熔盐电解质实现乏燃料干法后处理中铀、钚等锕系元素离子还原，使用镧系元素来模拟锕系元素并通过循环伏安法研究La(Ⅲ)在离子液体N-甲基-N-丙基哌啶双(三氟甲基磺酰)亚胺(MPPiNTf2)中的电化学行为。结果表明：La(Ⅲ)在MPPiNTf2中铂电极上的还原反应为不可逆过程，其在MPPiNTf2中的扩散系数为2.79×10-7cm2/s（323 K），反应活化能为99.4 kJ/mol。电沉积实验表明，在离子液体MPPiNTf2中采用恒电位电解法（–2.9 V(vs.Pd)）实现了金属镧的沉积。

Abstract:

This work applied lanthanide ions to simulate the actinides in order to use the room temperature ionic liquids as the electrolytes as a substitute for chloride high temperature molten salt to attain the goal of reducing the actinide such as uranium or plutonium?in the nonaqueous reprocessing applications of spent nuclear fuel. The electrochemical behavior of La(III) in the ionic liquid, N-methyl-N-propylpiperidinium bis(trifluoromethylsulfonyl)imide (MPPiNTf2), has been investigated by cyclic voltammetry. The results indicate that the reduction of La(III) is irreversible. The diffusion coefficient and the energy of activation of La(III) in ionic liquid MPPiNTf2 are 2.79×10-7 cm2/s at 323 K and 99.4 kJ/mol, respectively. Controlled potential electrolysis of a solution of La(Ⅲ) in MPPiNTf2 at –2.9 V (vs.Pd) results in the deposition of metallic lanthanum.