The distribution coefficient (K-D) of trace nickel on an iminodiacetate-che
lating resin Chelex 100 increased with pH to a peak value close to 2 000 00
0 ml/g at pH of about 5. At higher pH values the K-D dropped to 5000 ml/g d
ue to competition of an unidentified complexing agent, in equilibrium of th
ree-component Na/H/Ni ion-exchange system, H/Ni exchange was found to be do
minant in the pH range up to 8 and in Na concentration up to 6 mol/l. The p
ractical ion-exchange capacity for nickel was 2.15 mmol/g (4.3 meq/g). (C)
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