Innovative low-energy enrichment of sulfuric acid using PVDF-HFP anion exchange membranes with acid-blocking properties

PVDF-HFP-Based Pioneering Anion Exchange Membranes for Advanced Sulfuric Acid Enrichment with Reduced Water Mobility

“…Electrostatic repulsive force interactions, grounded in the principles of Donnan theory, are typically an advantageous approach for impeding ion transmission. , It is worth noting that the greater the ion exchange capacity of the membrane, the higher the water content within it, which, in turn, promotes proton leakage. , This underscores the pivotal role of water in proton transport. Therefore, the capability to block protons can be reinforced through the incorporation of weakly dissociated anion exchange groups, the introduction of hydrophobic groups, and an increase in the degree of cross-linking. , For instance, Wang et al have devised a series of AEMs with acid-blocking attributes by grafting functional groups featuring tertiary ammonia onto the primary structure of PVDF. − While these membranes exhibit commendable acid stability, it is crucial to acknowledge that the ED process consumes significant energy due to the elevated surface area resistance. Research indicates that a more robust cross-linked structure can enhance the membrane’s efficacy in obstructing hydrogen transport and subsequently influence variations in energy consumption and the ultimate concentration during the ED process.…”

“…To mitigate this limitation, we explored a strategy of partial surface quaternization. 26 This method not only preserved a degree of acid enrichment capability but also improved the membrane's overall acid resistance. Despite these advancements, our research has yet to thoroughly examine the specific influence of weakly basic tertiary amine groups within a highly cross-linked matrix on the acid enrichment process.…”

“…However, the potential for significant water migration during quaternization, which could adversely affect the final acid concentration, was not adequately addressed in this approach. To mitigate this limitation, we explored a strategy of partial surface quaternization . This method not only preserved a degree of acid enrichment capability but also improved the membrane’s overall acid resistance.…”