Comparative study on the production of gluconic acid by electrodialysis and bipolar membrane electrodialysis: Effects of cell configurations

To produce gluconic acid from sodium gluconate, three types of cell configurations of bipolar membrane electrodialysis (BMED) and two types of cell configurations of electrodialysis (ED) were applied and the factors such as the current variation, conversion rate, current efficiency and energy consumption were compared. The results indicated that the BMED2C-C cell configuration (two-chamber BMED with cation exchange membrane) had the better overall performance than the BMED2C-A configuration (two-chamber BMED with anion exchange membrane) and the BMED3C configuration (three-chamber BMED), and the ED3C configuration (three-chamber ED) had the better overall performance than ED4C configuration (four-chamber ED). An industrial production model was set, and the production cost of gluconic acid was estimated to be 0.25 US$/kg for BMED2C-C and 0.067 $/kg for ED3C, respectively. Taking account of the calculated value for sodium hydroxide, the cost of BMED2C-C will be 0.104 $/kg, which was less than the one of traditional production. Though ED3C has the lowest production cost, it produces the by-product sodium sulfate which needs to be handled further.