COLLECTION OF METAL IONS ON CHELATE RESIN S OF MALONIC-ACID DIHYDRAZIDES-FORMALDEHYDE SERIES

The chelate resins of malonic acid dihydrazides-formaldehyde series, s uch as MDH-FA, Et . MDH-FA and Bu . MDH-FA, were synthesized by the po lycondensation of malonic, ethylmalonic and butylmalonic acid dihydraz ides (MDH, Et . MDH and Bu . MDH) with formaldehyde (FA), and the coll ecting ability for Mn2+, Co2+, Ni-2+, Cu2+, Zn2+ and Cd2+ was investig ated by the batch and column methods. The collecting efficiency for th ese metal ions decreased in the order of MDH-FA>Et . MDH-FA>Bu . MDH-F A. By the batch method, the collecting efficiency of metal ions on the MDH-FA and Et . MDH-FA resins indicated the maxima values at pH 5.5-7 .0 for Ni2+ and Cu2+, and at pH about 7.5 for Co2+, and increased with pH for the other metal ions. When the aqueous solution of pH 5.5 cont aining each metal ion of about 10 ppm was flowed down from the upper p art of column (10 mm phi x 40 mm) packed with the MDH-FA or Et . MDH-F A resin, Cu2+ was almost completely collected, though the collection s uffered a small contamination from Ni2+ and Zn2+. On the other hand, t he MDH-FA resin was able to collect the metal ions of six kinds with t he collecting efficiency more than 85% from the aqueous solution adjus ted to pH 7.8.