Zirfon Porous Membrane (PPS85a, UTP220, UTP500, ALK12a) for Alkaline Water Electrolyzer, CAWEZPM

Zirfon is an industry-standard separator/membrane technology specifically engineered for alkaline water electrolyzers (AWE). It is a composite material, typically consisting of a polymer matrix (often polysulfone) filled with hydrophilic ceramic particles (usually zirconium oxide, ZrO2).

It uses an asymmetric organic polymer matrix—typically polysulfone (PSU)—reinforced with an internal fabric mesh (like polypropylene or PPS) to provide mechanical tensile strength and prevent sagging or tearing in large-scale industrial stacks. Zirconium oxide (ZrO2) nanopowder is embedded heavily throughout the polymer matrix. The ZrO2 serves a critical purpose: it makes the inherently hydrophobic polymer highly hydrophilic (water-wettable). It has a highly controlled porosity (typically around 50% to 60%) with a mean pore size of roughly 0.15 μm and a maximum pore cut-off around 0.5 μm.

Because the pores are macroscopic compared to molecular dimensions, gas separation and ionic conductivity are governed by competing physical mechanisms: (1) Ionic Conductivity via Tortuosity: OH- ions do not hop through the polymer itself; they travel through the liquid KOH trapped inside the membrane's tortuous pore network. The ionic resistance is heavily dependent on the bubble effect. Keeping H2 and O2 separate relies completely on the capillary pressure of the water-filled pores. Because the ZrO2 renders the pores completely wetted by the liquid electrolyte, it requires a significant physical pressure difference—known as the bubble point pressure (often greater than 1 to 2 bar)—for a gas bubble to force its way through a pore. As long as the differential pressure between the anode and cathode loops is kept below this threshold, gas crossover remains extremely low.

A larger sheet size of 20cm*20cm also can be supplied upon request

Use Note:

(1) Rinsing with DI water: 30min-12 h to increase the wettability and fully open the microporous structures.

(2) KOH activation: Immersion in 20-30 wt% KOH at 60°C for 2-24 h.

(3) Vacuum Degassing: Remove the bubbles inside porous structure for 10-20 min under vacuum level ≤ 0.08 MPa.

References:

1. K. Denk, et al., Mass transfer limitation phenomena across the separator in a zero-gap alkaline water electrolysis stack: Anion-selective polymer electrolyte membrane vs. Zirfon™ Perl UTP 500 case study, Chemical Engineering Journal, 2024, 479, 147354 
2. Q. Sun, et al., A Zirfon-type membrane based on exfoliated layered double hydroxide for advanced alkaline water electrolysis, International Journal of Hydrogen Energy, 2025, 182, 151819