Electrolytic hydrogen production from acidified wastewater effluent

Area of Science:

• Sustainable Energy
• Electrochemistry
• Water Treatment

Background:

• Current water electrolyzers require high-purity water, straining freshwater resources and increasing costs.
• Reclaimed water (RW) from wastewater treatment is a potential alternative, but its impurities can affect electrolyzer performance and lifespan.

Purpose of the Study:

• To investigate the impact of RW impurities on water electrolysis systems.
• To develop a cost-effective method for utilizing RW in hydrogen production.

Main Methods:

• Lab-scale water electrolysis systems were used to characterize the effects of RW impurities.
• Reclaimed water feedstock was acidified to assess its impact on electrolyzer stability and performance.

Main Results:

• RW impurities, primarily cations, contaminated the electrolyzer membrane.
• Acidifying RW extended electrolyzer stability from 8 hours to over 300 hours at 150 mA cm⁻².
• This acidification reduced costs by 46.9% and energy intensity by 61.8% by eliminating multi-stage pre-treatment.

Conclusions:

• Reclaimed water electrolysis is practically feasible for clean hydrogen production.
• Acidification is an effective strategy to mitigate RW impurity impacts, enhancing system stability and economic viability.
• This approach supports the integration of wastewater facilities into the clean energy transition.