Desalination of Fermented Broth Containing 1,3-Propanediol by Electrodialysis

The desalination of fermented broth containing 1,3-propanediol by electrodialysis was studied. The relationship between fermentation broth conductance and temperature, effects of membrane pair voltage, pretreatment with flocculation or filtration, initial pH of fermented broth on desalination, and reuse time of membrane were also investigated. It is found that the conductance of fermented broth is linearly related to temperature, the correct coefficient of temperature is 0.0217; the optimal operation voltage over membrane pair is 1.3~1.5 V, the longer the time taken for desalination, the more loss of 1,3-propanediol, flocculation with chitin will decrease the concentration of protein in broth, then alleviate the fouling process of membrane, and improve the efficiency of desalination. Initial broth pH has a noticeable affection on desalination in the pH range of 5~8, and the lower the pH of broth, the lower the resistance of membrane pair. So adjusting broth pH to an acidic condition will accelerate the rate of desalination. After using 15 times, membranes should be cleaned with NaOH and NaCl solution for the reason of fouling.