solvent extraction and transport of rare earth metal ions using 5.11.17.23-tetra-tert-butyl-25,27-bis (diethylcarbomoylmethoxy)-26,28-dihydroxy calix[4]arene

the solvent extraction of rare earth metal ions from nitrate solutions by 5.11.17.23-tetra-tert-butyl-25,27-bis(diethylcarbamoylmethoxy)-26,28-dihydroxycalix[4]arene (l) in 1,2-dichloroethane has been investigated. the alalysis of the extraction equilibrium obtained from a mixture of la3+, eu3+, er3+ and y3+ revealed that the extracted species have a 1:1 metal/ligand ratio. the intra-group separation efficiencies of the ligand have been evaluated in a competitive extraction and transport of 11 rare earth metal ions (la3+, pr3+, nd3+, sm3+, eu3+, gd3+, dy3+, ho3+, yb3+ and y3+). the transport experiment has been performed through a supported liguid membrane containing the ligand in o-nitrophenyl hexyl ether (nphe). the distribution ratio and the flux of the ions generally increases as the atomic radii decrease.