Bipolar Membrane Electrodialysis for Cleaner Production of Gluconic Acid: Valorization of the Regenerated Base for the Upstream Enzyme Catalysis

Abstract

Bipolar membrane electrodialysis (BMED) is an environmentally friendly, high-effective technique for the cleaner production of gluconic acid. However, the unsatisfactory purity and low concentration of the regenerated base limit the applicable field of the byproduct for further utilization. In this study, BMED was applied for the cleaner production of gluconic acid from the perspective of the regenerated base. First, four types of cation-exchange membrane were screened for the BMED process by evaluating the performances of current efficiency, purity of regenerated base, and energy consumption. The BMED performances follow the order of CMX > TWEDC > CJMC-5 > CJMC-3. Furthermore, the effects of current density, the volume ratio between salt and base compartment on the BMED performances were optimized. A high base purity of 96.6% was obtained at a current density of 40 mA/cm 2 , while a high base concentration of 4.58 mol/L could be reached by applying a high volume ratio of 5:1 between the salt and base compartment. Moreover, the mechanism on the leakage of organic salts into the regenerated base was elucidated. The purity of the regenerated base was attributed to diffusion and electromigration. Diffusion dialysis experiments demonstrated that the permeability of gluconate through the CMX was 4.7 times of that through the BP-1. It was also found that the leakage of gluconate into the base could be alleviated at a low current density ranging from 20 to 50 mA/cm 2 . Finally, the regenerated base was subjected to the enzyme catalyst experiment for conversion of glucose into gluconate. This proof-of-concept study demonstrates that the regenerated base from the BMED process could be valorized to the upstream route for a closed-loop cleaner production.

A Sustainable Electrochemical Method for the Production of Vanadium Pentoxide Using Bipolar Membrane Electrodialysis

“…This phenomenon was abnormal compared with the various BMED studies in the literature. 30,31,33,35,36 Generally, the concentration of acid produced by BMED increased with an increase in current density because the water splitting rate was accelerated at high current density. 30,31,33,35,36 However, in our case, the discrepancy phenomenon is attributed to the competition transport between V 2 O 7 4− and OH − as well as the dissociation balance limitation of the polyvanadate.…”

“…30,31,33,35,36 Generally, the concentration of acid produced by BMED increased with an increase in current density because the water splitting rate was accelerated at high current density. 30,31,33,35,36 However, in our case, the discrepancy phenomenon is attributed to the competition transport between V 2 O 7 4− and OH − as well as the dissociation balance limitation of the polyvanadate. At a low current density of 10−20 mA/cm 2 , there was little amount of water splitting OH − in the salt compartment due to a weak electric driving force.…”

“…Bipolar membrane electrodialysis (BMED), an environmentally friendly technique that enables the conversion of salts into the corresponding acids and bases, creates possibilities for the avoidance of the vanadium ammonium precipitation procedure. By taking advantage of intensive water splitting in the bipolar membrane under a reverse bias, the BMED technique has gained great commercial interest and is widely used for a variety of applications such as acid/base production, − cleaner production, − environmental protection, − and CO 2 reduction, ,− among others. − However, to the best of our knowledge, there are no studies that investigate the preparation of vanadium oxide using the BMED technology. Compared with common inorganic salts, vanadium is a group VB element.…”

Preface for the Jim Yang Lee Festschrift

“…18 Wang et al optimized the bipolar membrane electrodialysis for clean production of gluconic acid from the corresponding regenerated base, in terms of the type of cation-exchange membranes and operational parameters. 19 To facilitate the industrial application of nanofiltration diafiltration for effective separation of small molecules, Wang et al modeled and compared the energy consumption in the continuous feed diafiltration and intermittent feed diafiltration processes. 20 Xu et al reported an imine-bond-based reversible cross-linking approach for amine-terminated polybutadiene, giving rise to an easily recyclable telechelic rubber.…”

“…By immobilizing poly­(ionic liquid) brushes on the surface of metal–organic-framework (MOF) UiO-66-(OH) 2 , Yang et al improved the dispersity of porous MOFs in poly­(ether- block -amide) matrix, producing mixed matrix membranes that manifest good separation selectivity and permeability for CO 2 and N 2 . Wang et al optimized the bipolar membrane electrodialysis for clean production of gluconic acid from the corresponding regenerated base, in terms of the type of cation-exchange membranes and operational parameters . To facilitate the industrial application of nanofiltration diafiltration for effective separation of small molecules, Wang et al modeled and compared the energy consumption in the continuous feed diafiltration and intermittent feed diafiltration processes .…”