Feasibility and performances of an electrodialysis stack fully composed of hierarchical ion-exchange membranes for demineralization of a complex food solution

Abstract

Recent studies have highlighted hierarchical ion-exchange membranes (hIEMs), fabricated by coating a functional layer on a porous substrate, as promising alternatives to commercial ion-exchange membranes for whey demineralization. These innovative hierarchical anion-exchange membranes (hAEMs) and cation-exchange membranes (hCEMs) had never been evaluated in combination in an ED system for food matrices demineralization such as whey. In this study, the impacts of two membrane configurations (EbN-1/ UL6 and EbN-1/EbS-2) and their performances (energy consumption, current efficiency, etc.) for whey demineralization by ED were evaluated and compared to commercial membranes (AMX/CMX). Although the systems fully composed of hIEMs took longer to demineralize up to 70 % the 18 % sweet whey solution compared to the commercial reference (EbN-1/UL6: 86.0 ± 0.7 min vs. reference: 62.7 ± 1.7 min), demineralization was successful. For EbN-1/EbS-2, although the global system resistance increased significantly throughout the runs (25.5 Ω vs 53.3 Ω), the energy consumption was similar to the reference (15.00 ± 0.64 Wh vs 14.33 ± 0.27 Wh). One membrane configuration, the EbN-1/UL6 system, stood out and its performances were successful enough to challenge commercial ED set-ups. This study proved the applicability of an ED system fully composed of hIEMs for ED applications to complex food systems.