STUDIES ON SELECTIVE ADSORPTION RESINS .33. BEHAVIOR OF MACRORETICULAR CHELATING RESINS CONTAINING PHOSPHINIC AND OR PHOSPHONIC ACID GROUPSIN THE ADSORPTION OF TRIVALENT LANTHANIDES

The effect of the crosslinking and the porosity of the chelating resin s containing phosphinic and/or phosphonic acid groups (RSP and RCSP) o n uptake of trivalent lanthanides was studied; RSP and RCSP were prepa red by hydrolysis of condensation products of phosphorus trichloride w ith styrene-divinylbenzene copolymer beads (RS) and with chloromethyla ted RS, respectively. From a series of RSs synthesized by systematical ly changing the amount of the crosslinker (divinylbenzene) or the poro gen (2,2,4-trimethylpentane), RSPs and RCSPs with different degrees of crosslinking and with different porosities were derived. Measurements of their uptake of La (III), Gd (III), or Yb (III) have clarified tha t RSP and RCSP with moderately crosslinked highly porous structures ex hibit high capacities toward the lanthanides. Using these optimized RS P and RCSP and their respective oxidized derivatives RSPO and RCSPO, t he distribution of all lanthanides(III) except for Pm(III) from aqueou s hydrochloric acid solutions (0.1-1M) was examined. The distribution of each lanthanide(III) at a given concentration of the acid increases in the order RCSPO almost-equal-to RCSP < RSPO < RSP. Their lanthanid e selectivity patterns resemble one another; the selectivity increases with increasing the atomic number of the lanthanides except for the e lements from Sm to Ho. In order to illustrate usefulness of these resi ns in the separation of lanthanides, the chromatographic separation of La(III), Nd(III), and Sm(III) was conducted using columns packed with RCSP. The three lanthanides were successfully separated by the elutio n with 0.5M hydrochloric acid solution without use of any organic comp lexing reagents, such as EDTA. (C) 1994 John Wiley & Sons, Inc.