Systematic Study of the Impact of Pulsed Electric Field Parameters (Pulse/Pause Duration and Frequency) on ED Performances during Acid Whey Treatment

Abstract

Processing acid whey is still a challenge for the dairy industry due to its high lactic acid and mineral contents. Their removal processes represent a high investment and running cost in addition to significant production of polluting effluents. A previous study showed that the use of electrodialysis with the application of pulsed electric fields (PEFs) was sufficiently efficient to produce dryable acid whey with reduced scaling issues during the process. In the present work, eight PEF conditions using different pulse/pause durations and frequencies were tested for 1) process optimization and 2) understanding of the underlying mechanisms involved in PEF process improvements. Best results were obtained for PEF conditions (5 s/5 s) and (15 s/15 s) with almost complete scaling mitigation and minimal energy consumption (5.3 ± 0.4 Wh/g of lactic acid vs. 9.33 ± 1.38 Wh/g for continuous current). Longer pause times also led to better divalent ion demineralization at the expense of sodium elimination induced by stronger affinity with the membrane and longer retention times. For the first time, PEF parameters of relatively low frequencies (<1) were studied in sub-limiting current conditions on a complex solution such as acid whey.

How Overlimiting Current Condition Influences Lactic Acid Recovery and Demineralization by Electrodialysis with Nanofiltration Membrane: Comparison with Conventional Electrodialysis

“…In Dufton et al, 64% of demineralization was reached after 180 min with the CACAC configuration, mainly in the underlimiting condition. In the present study, a higher demineralization rate (77.2%) was obtained in 30 min in the overlimiting current [41]. These results confirmed that in the overlimiting current condition, EVs generated at the AEM can lead to a better demineralization of acid whey, as presumed in the literature [22,33].…”

Effect of Surface Inhomogeneity of Ion-Exchange Membranes on the Mass Transfer Efficiency in Pulsed Electric Field Modes

“…It should be noted that the frequencies at which the maximum mass transfer rate for a given membrane is observed become quite small (<0.1 Hz), and the optimal duty cycle for almost all membranes becomes 1/2. The optimal value of the duty cycle equal to 1/2 at overlimiting currents was also determined in [31,37], including the case of using homogeneous Neosepta membranes in electrodialyzers [58,59]. Probably, the surface inhomogeneity of the MK-40 membrane leads to the shift in the optimal frequency to a relatively low-frequency range.…”

“…The essence of the electrodialysis desalination of solutions using PEF modes is to alternate cycles of switching on and off the external electric field. It allows the reduction in concentration polarization and, as a result, increase in mass transfer rate [24,27,28], reduction in the rate of water dissociation at the membrane/depleted solution boundary [29], as well as the rate of precipitate formation in the electrodialyzer chambers during the processing of multicomponent solutions [30][31][32]. Nevertheless, energy consumption in the PEF mode should be greater [28].…”

“…Currently, the PEF modes are actively used in electrodialysis for processing complex solutions of the food industry [31,[37][38][39]. However, the effect of the surface properties of ion-exchange membranes on the process efficiency has not been studied enough.…”

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

“…Nevertheless, this special cleaning agent containing a surfactant and metal-chelator is very effective for treating the tobacco extract. To increase the viability of electrodialytic desalting of tobacco extract, an elaborate pretreatment [ 27 ] and other mitigation strategies such as reversal ED or pulsed electric field [ 46 , 47 , 48 , 49 ] need to be further developed.…”