Electrodialytic desalination of cheese whey was carried out using a pair of polymer cation exchange (Nafion 117) and inorganic membranes. The ceramic separator was modified with nanocomposite containing hydrated zirconium dioxide and basic bismuth nitrate. This amphoteric filler provides anion exchange ability of the composite membrane. This property is realized when at least one side of the membrane is in contact with an acidic solution. Ion transport through the membranes was shown to be determined by current, whey acidity, and also by composition of the solution in the concentration compartment of the electrochemical cell. It was shown that whey desalination occurred under overlimiting current. Acidification of whey and decrease of the acid content in the concentrate suppress ion transport. The electrodialysis of whey and nanofiltration permeate allowed removal of up to 80 % of the mineral components in 5 h and 40 min, respectively. Preliminary ozonation of the permeate increased the rate of desalination.

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Organic-inorganic membranes were obtained by stepwise modification of poly(ethyleneterephthalate) track membrane with nanoparticles of zirconium hydrophosphate. The modifier was inserted inside pores of the polymer, a size of which is 0.33 μm. Inner active layer was formed by this manner. Evolution of morphology and functional properties of the membranes were investigated using methods of porosimetry, potentiometry and electron microscopy. The nanoparticles (4 to 10 nm) were found to form aggregates, which block pores of the polymer. Pores between the aggregates (4 to 8 nm) as well as considerable surface charge density provide significant transport numbers of counter ions (up to 0.86 for Na+). The materials were applied to baromembrane separation of corn distillery. It was found that precipitate is formed mainly inside the pores of the pristine membrane. In the case of the organic-inorganic material, the deposition occurs onto the outer surface and can be removed by mechanical way. Location of the active layer inside membranes protects it against damage.

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