Removal of Sulfate from Threonine Isoelectric Supernatant by Bipolar Membrane Electrodialysis
双极膜电渗析脱除苏氨酸母液中硫酸盐

The desalination of sulfate in threonine isoelectric supernatant by three-compartment electrodialysis with bipolar membrane was studied.The device performance during five successive batches of electrodialysis was investigated.In addition,the area resistance of ion-exchange membranes before and after batch operation was measured to detect the membrane fouling.The results showed that the transform rate of sulfate in threonine isoelectric supernatant reached 97%,and H+ concentration of 0.49 mol/L and OH- concentration of 0.44 mol/L were obtained by the electrodialysis in acid and base cells,respectively.Whereas,the average current efficiency and energy consumption of the three-compartment electrodialysis with bipolar membrane calculated on the basis of cations were 60.33% and 229.37 kW·h/kmol,respectively.With increasing of batch runs and prolonging of operation time,the energy consumption of unit flux and average stack resistance increased,and average current efficiency and flux decreased,the device performance was deteriorated.Moreover,the area resistance of anion and bipolar membranes was increased by 44.8%(1.77 Ω·cm2) and 19.5%(0.91 Ω·cm2),respectively,which was caused by membrane fouling.