Dialysis of nickel sulfate with simultaneous monitoring of changes of solutions dialyzed

The paper deals with dialysis of aqueous solutions of nickel sulfate against aqueous sulfuric acid through a cation-selective membrane NEOSEPTA CM-2 in batch arrangement. The concentration changes of both dialyzed and stripping solutions were monitored spectrophotometrically during the dialysis. At the same time, also the volume changes of both solutions were measured; these changes are due to the osmotic flow of water through the membrane caused by different concentrations of ions in the two solutions dialyzed. The experimental data were evaluated on the basic of a mathematical model based on phenomenological description of the process. Extrapolation from the dependence of total dialysis coefficients on stirring rate of both solutions gave the permeability coefficient of the membrane for the given of NiSO4/H2SO4