Ion conductive spacers for the energy-saving production of the tartaric acid in bipolar membrane electrodialysis

One of the common problems for the production of organic acid using electrodialysis technology is the relative high energy consumption due to their weak dissociated ability. Enlightened by our previous work [Journal of Membrane Science 341 (2009) 246–251 and Journal of Membrane Science 366 (2011) 266–271] in which the ion exchange resin were filled in the product compartments, a conducting spacer instead of the traditional non-conducting spacer was adopted for the convenience of the operation to facilitate ion transportation during the production process of the tartaric acid by the bipolar membrane electrodialysis technology. Herein, the cell voltage, the current efficiency and the energy consumption were investigated and compared before and after the use of the conductive spacers, respectively. Furthermore, the process economics were all evaluated and compared with the traditional methods. The experimental results showed that the conductive spacer can effectively facilitate the transport of the hydrogen ions in the product compartment and then effectively decrease the energy consumption of the tartaric acid production by the process. But, on the other hand, the simultaneous effects resulting from the hydrogen ion short circuit, including the reduced producing rate and current efficiency, also took place.