Two new oxime containing polymers, poly(salicylaidoxime-3,5-diyl (piperazine N,N'-bismethylene)), polymer I, and poly(2,4-dihydroxy-benzaldoxime-3,5-diyl (piperazine N,N'-bismethylene)), polymer II, were prepared through Mannich-type condensation of the appropriate hydroxy benzaldoxime with formaldehyde and piperazine. The sorption properties of these polymers towards the trivalent lanthanide ions, Gd3+, Tb3+, Sm3+, Nd3+, and La3+ were studied by a batch equilibration technique as a function of contact time, pH, and counter ion. Polymer II exhibited improved chelation characteristics in comparison with polymer I and displayed faster rates of metal ion uptake and relatively higher capacities and selectivities. (C) 2005 Elsevier B.V. All rights reserved.