How electrodialysis configuration influences acid whey deacidification and membrane scaling

Abstract

With the rising popularity of Greek-style yogurts in the past few years, the production of acid whey has drastically increased. If sweet whey is usually further processed, the acid whey valorization comes with challenges because its drying is jeopardized by its high mineral and organic acid contents. For this reason, prior demineralization and deacidification are usually performed at industrial scale using a combination of ion exchange resins and electrodialysis. This whole process represents large amounts of resources and energy consumption as well as an important production of effluents. The optimization of the electrodialysis technique, currently the focus of a few studies, could result in the replacement of the serial processes and would provide a cost-effective and eco-efficient alternative. In this work, the demineralization and deacidification of acid whey were compared via 2 electrodialysis configurations: one conventional and one using bipolar membranes. Both configurations allowed to reach interesting demineralization (67%) and deacidification (44%) rates. However, even though the appearance of fouling or scaling has never been reported, scalings of different natures were observed on membranes using both configurations. Amorphous calcium phosphate was identified on the anion exchange membranes for both configurations while calcite and brucite were identified on cation exchange ones using the bipolar membrane configuration. These scaling formations were linked to the migration of divalent ions and water splitting phenomenon caused by a high demineralization rate or by an already formed significant scaling.

Electrodialytic Desalination of Tobacco Sheet Extract: Membrane Fouling Mechanism and Mitigation Strategies

“…In this case, the dissociated OH - ions of water will combine with Ca 2+ and Mg 2+ ions and will precipitate on the surface of cation exchange membranes. The substantial inorganic scaling fouling in the cation exchange membrane is consistent with numerous studies [ 41 , 42 , 43 , 44 ]. Cifuentes-Araya and co-authors [ 42 ] found that divalent cations precipitation with OH - ions produced by significant water splitting was reinforced by an important OH - leakage through CEM that highly alkalinized the membrane interfaces, and also counteracted the demineralization.…”

“…In a previous study [ 43 ], the authors systematically investigated the fouling nature evolutions along with different ED trials, and they found that amorphous calcium carbonate appeared on cation exchange membrane due to intense water-splitting reaction. Dufton and co-authors [ 44 ] have studied the fouling of ED for acid via deacidification, and they found the calcite and brucite were identified on the cation exchange membrane. The high solution alkalinity by the water dissociation was the reason for the fouling.…”

The Novel Strategy for Increasing the Efficiency and Yield of the Bipolar Membrane Electrodialysis by the Double Conjugate Salts Stress

“…The energy consumption of acid was determined by not only the stack resistance but also the concentration of H 2 SO 4 produced in the acid compartment, as shown in Equation (2). Thus, the higher energy consumption obtained in the BP-A-BP configuration resulted from the low conductivity of the H 2 SO 4 solution [32].…”

Feasibility of using electrodialysis with bipolar membranes to deacidify acid whey

“…These phenomena are sufficiently covered in respective reviews (Suwal et al ; Mikhaylin and Bazinet ). The fouling issue is also known in EDBM applications (Wang et al ; Mikhaylin and Sion ; Haddad et al ; Dufton et al ; Merkel et al ). It is important that the electrogeneration plays a crucial role in fouling formation.…”

“…Recently, several reports on EDBM application in acid whey treatment have emerged. Dufton et al () obtained acid whey with lowered content of lactic acid using conventional ED stack and one with bipolar membranes. Furthermore, Merkel et al () tested two alternative EDBM stacks in the processing of acid whey nanofiltration retentate.…”