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Removal of Cr(III) ions from salt solution by nanofiltration: experimental and modelling analysis

Kowalik-Klimczak A., Zalewski M., Gierycz P.

Polish Journal of Chemical Technology

2016

Vol. 18, nr 3

10--16

The aim of this study was experimental and modelling analysis of the nanofiltration process used for the removal of chromium(III) ions from salt solution characterized by low pH. The experimental results were interpreted with Donnan and Steric Partitioning Pore (DSP) model based on the extended Nernst-Planck equation. In this model, one of the main parameters, describing retention of ions by the membrane, is pore dielectric constant. In this work, it was identified for various process pressures and feed compositions. The obtained results showed the satisfactory agreement between the experimental and modelling data. It means that the DSP model may be helpful for the monitoring of nanofiltration process applied for treatment of chromium tannery wastewater.

Electrokinetic Properties of Nafion 117 in NaCL+KCl Solutions

Koter S.

Polish Journal of Chemistry

2001

Vol. 75, nr 7

1001-1017

The applicability of the extended Nernst-Planck equation with the homogeneous distribution of ions and the capillary model (the Boltzmann distribution of ions) to the description of electrokinetic phenomena in the system Nafion 117|0.1 M mixture of NaCl and KCl has been discussed. It has been found that only the capillary model can reasonably describe those phenomena, simultaneously preserving the Onsager reciprocity relation. The extended Nernst-Planck equation gives unsatisfactory results by either strongly breaking the reciprocity relation or, assuming the reciprocity relation (_i must be 1), leading to large discrepancies between the hydrodynamic permeability and the electrical conductivity. The interpretation of _i in terms of the capillary model has been given. _i < 1 for counterions and _i > 1 for coions result from the radial concentration profiles of those ions and of the convective velocity. The dependence of _i on the kind of acting force has been proved.