Integration of conventional electrodialysis and electrodialysis with bipolar membranes for production of organic acids

To reduce the cost of electrodialysis with bipolar membranes (EDBM) for production of organic acids, conventional electrodialysis (CED) was integrated with EDBM, i.e., CED supplied concentrated organic salts as the feed to EDBM. To assess the adaptability of this integration, sodium gluconate was chosen as a model agent for production of gluconic acid. Results indicated that this integration could achieve an apparent current efficiency higher than 100% and low energy consumption due to the inward concentration of gluconate and electrode reactions in CED. Besides, the process cost of CED–EDBM was estimated to be $0.31 kg−1, which was less than that of EDBM ($0.39 kg−1). This integration not only made the production cost-effective but also kept the operation of EDBM stable.