Extraction of caesium(I) from HNO_3 medium using room temperature ionic liquid containing calix[4]crown ligands as the selective extractants

摘要

Studies on the extraction of Cs(I) from nitric acid medium were carried out using three commercial calix-crown ligands, viz. calix[4]arene-bis-crown-6, calix[4]arene-bis- 1,2-benzocrown-6 and calix[4]arene-bis-2,3-naphthocrown-6 dissolved in different room temperature ionic liquids (RTILs), viz. 1-butyl-3-methyl-imidazolium hexafluorophosphate (C4mim·PF_6), 1-hexyl-3-methyl-imidazolium hexafluorophosphate (C6mim·PF_6) and 1-octyl-3-methyl-imidazolium hexafluorophosphate (C8mim·PF_6). The distribution ratio of Cs(I) decreased with increased alkyl chain length of RTILs. The effect of nitric acid concentration on distribution behaviour of Cs(I) by calix[4]arene-bis-1,2-benzocrown-6 was investigated. The extraction of Cs(I) from HNO3 was found to be exothermic and extraction was found to be enthalpy driven. Selective extraction of Cs(I) could be achieved from a mixture of various fission product elements like Tc, Mo, Zr, Ce, Ru, La, Ba, and Sr.