Why Electrolyte Filtration Is Critical for Green Hydrogen Production
Sep, 2026
Electrolyzers are the heart of green hydrogen production. These devices split water into hydrogen and oxygen when supplied with electricity. There are four types of electrolyzer technologies currently available.
- Alkaline electrolyzers
- PEM - (polymer electrolyte membrane)
- SOEC - (solid oxide electrolyzer cell)
- AEM - (anion exchange membrane)
Why does the industry prefer alkaline electrolyzers?
Alkaline electrolyzer technology is the most mature and requires the lowest CAPEX. PEM electrolyzers are commercial but comparatively expensive while SOEC and AEM technologies are still under demonstration. Consequently, alkaline electrolysis is the chosen technology for many of the largest green hydrogen projects announced globally.
Why Is It Called an Alkaline Electrolyzer?
The technology is called "alkaline" because it uses a highly corrosive 30-40% potassium hydroxide (KOH) solution as the electrolyte feedstock. The electrolyte is under constant circulation within the electrolyzer and, over time, can corrode electrolyzer components, causing contamination from very fine particles.
Typical hydrogen electrolyzer configuration
Why Is Electrolyte Filtration Important?
Safety of facility:
Fine particle contaminants can cause significant issues in green hydrogen production. These particles can accumulate and block small bore piping and bends within the electrolyzer, potentially resulting in process upsets.
An investigation into a 1975 electrolyzer facility explosion in the UK identified "blockage by sludge of the narrow electrolyte passages" as the main cause.
Performance of electrolyzers:
Fine particles can contaminate system components such as electrodes and diaphragms, reducing their performance and service lifetime.
IRENA highlights the need to "mitigate catalyst poisoning/deactivation by foreign elements from electrolyte" as a key activity for improving alkaline electrolyzer performance. Electrode manufacturers have also begun specifying higher electrolyte cleanliness requirements to support performance and service life.
Electrolyte samples from an operating unit with a nominal filter (before) and after filtration through Pall's absolute rated filter. In the foreground, a sample of typical particulate contaminant removed from the electrolyte
How Can Pall Help with Electrolyte Filtration?
Every green hydrogen project has unique electrolyte filtration requirements. Alkaline electrolyzer technologies vary considerably between suppliers and filtration requirements can differ from project to project.
Pall offers a range of filtration solutions to suit different requirements. For chemical compatibility with electrolyte, filter elements are available in:
- Polypropylene
- Polyphenylene sulfide
- Fluoropolymer
- High-alloy steel construction
For particle removal, Pall offers absolute-rated filters with sub-micron through 50-micron ratings.
How Is the Right Electrolyte Filter Selected?
Before making a filter selection, it is important to understand the nature of contamination within the system. Understanding particle size distribution and chemical composition helps identify a filter that protects the electrolyzer while balancing capital and operating costs.
Pall experts can analyze electrolyte samples and use contamination analysis to help determine appropriate filtration solutions for individual operating conditions.
Key Takeaways
- Alkaline electrolyzers remain a widely adopted technology for green hydrogen production.
- Electrolyte contamination can affect both safety and performance.
- Fine particles can impaact piping, electrodes and diaphragms.
- Electrolyte filtration helps support cleaner electrolyte and reliable operation.
- Pall offers filtration solutions for a range of electrolyte filtration requirements.
Talk to a Green Hydrogen Filtration Expert