Whey electrodialysis using organic-inorganic membranes

Organic-inorganic membranes based on heterogeneous ion exchange polymer supports, which were modified with hydrated zirconium dioxide (anion exchange membrane) and zirconium hydrophosphate (cation exchange separator), were used for whey desalination as well as for concentrate and permeate of whey nanofiltration. Comparing with pristine polymer membranes, the composite materials are characterized by stability against fouling inside pores. The membranes were applied to desalination of whey and products of its baromembrane treatment. Exponential decay of electrical conductivity over time has been found for the solutions being purified. The membrane resistance grew simultaneously

Treatment of dairy effluent model solutions by nanofiltration and reverse osmosis

Introduction. Dairy industry generates a large amount of wastewaters that have high concentrations and contain milk components. Membrane processes have been shown to be convenient for wastewater treatment recovering milk components present in wastewaters and producing treated water. Materials and methods. The experiments were carried out in an unstirred batch sell using nanofiltration membranes OPMN-P (ZAO STC “Vladipor”, Russian Federation) and reverse osmosis membranes NanoRo, ZAO (“RM Nanotech”, Russian Federation). The model solutions of dairy effluents –diluted skim and whole milk were used. Results. The nanofiltration and reverse osmosis membranes showed the same permeate flux during the concentration of model solutions of dairy effluents. The reason of this was likely membrane fouling with feed components. The fouling indexes indicated the fouling factor that was higher for RO. The higher permeate quality was obtainedwith RO membranes. The NF permeate containing up to 0.4 g/L of lactose and 0.75 g/L of mineral salts can be discharged or after finishing trеatment (e.g. RO or other) can be reused. The obtained NF and RO retentate corresponds to milk in composition and can be used for non-food applications or as feed supplement for animals. Conclusions.The studied RO and NF membranes can be used for concentration of dairy effluents at low pressure. They showed better performance and separation characteristics comparing with data of other membranes available in the literature

Whey desalination using polymer and inorganic membranes: Operation conditions

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