Separation of nickel and chromium on a porous glass-packed column using nitric acid and citric acid as eluent

Experiments to separate nickel and chromium were carried out at 298 K on a porous glass packed-column using nitric acid and citric acid as an eluent. When nitric acid was used as an eluent, both metals were perfectly recovered in the concentration range of 0.02-0.05 mol/dm(3), and they were isocratically and perfectly separated at 0.02 mol/dm(3). When 0.1 mol/dm(3) citric acid was used as an eluent, both metals were perfectly separated in the range of pH 1.7-2.2, and isocratic elution was especially possible at pH 1.7 and at pH 2.2. It was considered that the perfect separation of both metals could be performed in this pH region, since generation of CrOH (2+) ion, which was eluted simultaneously with Ni2+ ion, was suppressed. It was found that separation performance was raised, since the retention volume of chromium was increased and that of nickel was hardly changed with decrease in the amount of both metals loaded.