A continuous mode operation of bipolar membrane electrodialysis (BMED) for the production of high-pure choline hydroxide from choline chloride

Choline hydroxide is an important chemical with multitude of applications. The current preparation methods of choline hydroxide have some drawbacks, such as low yielding, low purity, and high energy consumption. To overcome these shortcomings, an eco-friendly method for the preparation of choline hydroxide from choline chloride via using bipolar membrane electrodialysis (BMED) is proposed in this study. The BMED process was evaluated by systematically investigating the operation main parameters of membrane stack configuration, cation exchange membrane types, initial feed concentration and voltage drop, and finally obtained an optimum operation parameter. With the parameter conditions (the constant voltage drop of 12.5 V, the initial feed concentration of 0.4 M and the BP-1/CMX/AHA/JCM-II-05 membrane stack), the BMED process demonstrated an exceptional high conversion rate (86.84%), low energy consumption (0.7444 kWh.kg(-1)) and high current efficiency (84.60%). In addition, the Cl- content of the choline hydroxide converted to 45 wt% aqueous solution could be achieved as low as 321.75 ppm. Furthermore, the continuous mode operation was carried out to simulate the industrial manufacture. The obtained results demonstrated a promising potential application of BMED in the preparation of choline hydroxide.