Per- and polyfluorinated alkyl substances (PFAS for short) constitute a group of more than 10,000 synthetic chemicals. These compounds are characterized by an extremely stable carbon-fluorine bond.
PFAS are characterized by the following features:
- Water-, grease-, and dirt-repellent
- Heat- and chemical-resistant
- Extremely long-lasting (“eternal chemicals”)
- Virtually non-biodegradable
- Bioaccumulative in organisms and the environment
Because synthetic chemicals are virtually non-biodegradable in the environment, they continuously accumulate in water, soil, plants, and living organisms. Scientific studies link PFAS exposure to various health and environmental risks.
Environmental and Health Risks
PFAS are increasingly becoming a focus of environmental and health policy:
- Persistence: The half-life of many synthetic chemicals in the environment ranges from decades to centuries.
- Mobility: They enter the environment via industrial wastewater, landfill leachate, and airborne transport.
- Bioaccumulation: PFAS accumulate in the food chain and are now found in blood samples from people around the world.
- Health Effects: Scientific studies link exposure to these substances to:
- Elevated cholesterol levels
- Impaired immune function
- Thyroid Disorders
- Reduced fertility
- Low birth weight
- Increased Risk of Certain Types of Cancer
Due to the numerous risks involved, the European Chemicals Agency (ECHA) is working on a comprehensive restriction (REACH Regulation). To date, the legal framework has become increasingly stringent. These regulatory developments pose significant challenges for the hydrogen industry. This is because PFAS are used, for example, in PEM electrolysers.
Role in Hydrogen Technology
- Membrane material: The core component of many PEM electrolyzers consists of PFAS-containing membranes that transport protons between the electrodes.
- Binders: They improve the adhesion between catalyst particles and the support materials in the electrodes.
- Proton conductivity: They optimize the water absorption and proton transport properties of the catalytic layers.
- Long-term stability: Compounds containing perfluorinated and polyfluorinated alkyl substances enhance the chemical resistance of electrolyzer components in an acidic environment.
The current performance parameters of many PEM electrolysers are difficult to achieve without the use of these materials. This explains their widespread use despite known environmental concerns.
Alternatives for Hydrogen Production
The pressure to innovate is driving intensive research into PFAS-free solutions:
- Alternative Membrane Materials: Development of hydrocarbon-based proton-exchange membranes without fluorinated polymers.
- Inorganic binders: Use of titanium oxide, silicon dioxide, or other inorganic materials as binders.
- New coating technologies: Processes such as plasma technology, which do not require PFAS and also reduce the need for precious metals.
- Alkaline Electrolysers: Increased Focus on Alkaline Electrolysis Technology
Reducing and ultimately eliminating the use of PFAS is considered a crucial factor for the social acceptance and sustainability of hydrogen technology as an energy source of the future.
