Dehumidification via polymer electrolyte membrane electrolysis with sulfonated pentablock terpolymer

Proton exchange membrane (PEM) electrolytic air dehumidification is advantageous for its compact design and low operating voltage. In this study, a series of sulfonated pentablock terpolymer (NEXAR®) membranes at two different ion exchange capacities (IEC) of 1.0 and 2.6 meq g−1 were evaluated for PEM electrolytic dehumidification. Water vapor transmission rate (WVTR), water removal energy efficiency, and electrochemical analysis were performed under various humidity conditions (wet side = 100% relative humidity (RH), dry side = 10% or 50% RH) and applied potential directions (concurrent and countercurrent). Compared to the benchmark Nafion membrane at 0.9 meq g−1, the NEXAR® membrane at 1.0 meq g−1 exhibited higher water removal energy efficiency, while the NEXAR® membrane at 2.6 meq g−1 revealed higher WVTR, but lower energy efficiency due to higher water sorption. In all cases, concurrently applied potential resulted in higher water removal energy efficiency than countercurrent. Overall, this study demonstrates the NEXAR® membrane as a promising alternative to Nafion as a cost-effective and energy-efficient membrane in PEM electrolytic dehumidification.