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Leakage of mono- and divalent cations through the weak-base anion exchange membrane in the process of electrodialysis of H2SO4 and its metal salt mixture

Kultys M., Koter S., Gilewicz-Łukasik B., Koter I.

Ars Separatoria Acta

2011

No. 8

101-108

Experimental results on the separation of sulfuric acid from its mixture with sodium- and magnesium sulfate, respectively, by the electrodialytic method have been presented. The Selemion AVV membrane as anion-exchange membrane was used. It was found that the leakage of Na+ from the cathode to the anode side of the AAV was higher than that of Mg2+. The leakage of Na+ decreased with the acid concentration whereas that of Mg2+ increased. Surprisingly enough, the permeability of Na+ increased with the electric current density, indicating a substantial contribution of electroosmotic convection to the Na+ flow. The current efficiency of the anions transport (HSO4 -, SO4 2-) through the AAV hardly exceeded 50%. It was independent of the kind of salt present on the cathode side of the AAV.

Application of Molecular Descriptors to the Prediction of Retention in Organic Solvent Nanofiltration

Koter S., Gilewicz-Łukasik B., Nowaczyk A., Nowaczyk J.

Polish Journal of Chemistry

2009

Vol. 83, nr 12

2137-2152

An attempt to apply the molecular descriptors for the characterization of retention of solutes in organic solvent nanofiltration has been performed. The descriptors were calculated using the program Dragon. The geometry of each solute molecule has been optimized using GaussianŽ. Two linear equations relating the retention coefficient, R, with one or two descriptors have been tested using two sets of solutes. The first one (“soft” set) consisted of saturated and aromatic hydrocarbons (data of White, J. Membr.Sci., 205, 191 (2002)), the second one (“hard” set) contained the substituted aromatic hydro carbons with heteroatoms (data of Geens et al., J. Membr. Sci., 281, 139 (2006)). It has been found that the “soft” set of compounds is described reasonably well by both equations. The best descriptors belong to GET AWAY descriptors and Burdeneigen values. Regarding the “hard” set of compounds only the 2-descriptors equation yields a satisfactory fitting of R. Here the 3D-MoRSE descriptors are the best for 7 of 14 membrane-solvent systems.