Scientists Develop Iron-Based Filter That Removes PFAS 26 Times Better Than Activated Carbon

Scientists just made a breakthrough discovery that could revolutionize how we remove “forever chemicals” from drinking water. Researchers at Stevens Institute of Technology found that simple iron powder – much cheaper than the activated carbon used in most water filters – removes toxic PFAS chemicals 26 times more effectively per unit of surface area.

Even better: the iron powder keeps working even after it rusts. Here’s what this could mean for cleaning up our water supply.

The Discovery That Changes Everything

Most water filters today use activated carbon to remove PFAS and other contaminants. It works, but it’s expensive and has limitations. Now scientists have discovered that ordinary iron powder – the kind already used in some industrial water treatment – does the job much better.

The key findings:

• Iron powder removed 26 times more PFAS per unit surface area than activated carbon
• The iron powder (called microscale zero-valent iron or mZVI) costs less than activated carbon
• It still works effectively even after the iron rusts from being in water
• The rusted iron particles remained “very active” at removing forever chemicals

Why this matters: This discovery could lead to cheaper, more effective water treatment systems for communities struggling with PFAS contamination. It might also pave the way for better home filtration options.

How the Research Worked

Professors Xiaoguang Meng and Christos Christodoulatos, along with Ph.D. student Meng Ji at Stevens Institute of Technology, wanted to find the most efficient way to remove PFOS (one of the most common forever chemicals) from water.

Their experiment:

• Compared iron powder directly to activated carbon
• Tested how well each material removed PFOS from contaminated water
• Measured the surface area needed for effective removal
• Published their findings in Environmental Science & Technology in March 2025

The results were dramatic: The iron powder had a significantly higher removal capacity (21 mg/m²) compared to activated carbon (0.813 mg/m²). Using 10 grams per liter of iron powder reduced PFOS concentrations from 50 mg/L to 6 mg/L within just 8 hours.

What Makes Iron Powder So Effective

The scientists discovered that iron powder removes PFAS through a process called adsorption – the same basic process that activated carbon uses, but much more efficiently.

How it works:

• PFAS molecules stick to the surface of iron particles
• The iron provides more effective binding sites than carbon
• Even when the iron oxidizes (rusts), it maintains its ability to grab forever chemicals

The surprising rust discovery: Most people would assume that rusty iron wouldn’t work as well. But the research showed that when iron particles develop an iron oxide layer on their surface, they’re still highly effective at removing PFAS.

“The particles’ surface is covered by iron oxide, but it’s still very active,” said Professor Meng. This unexpected finding has major implications for real-world water treatment systems.

Why This Discovery Matters

Current water treatment options for PFAS are expensive and have limitations. This iron-based approach could change that:

Cost advantages:

• Iron powder costs significantly less than activated carbon
• It’s already mass-produced for other industrial uses
• The fact that it works even when rusty means longer filter life

Performance benefits:

• 26 times more effective removal per unit surface area
• Faster treatment times (8 hours vs. days for some other methods)
• Works at neutral pH levels (normal water conditions)

Real-world applications:

• Could make PFAS treatment affordable for small communities
• Might lead to better home filtration systems
• Useful for industrial wastewater treatment

Current Water Filter Technology

To understand why this discovery is significant, it helps to know how current PFAS removal works:

Activated carbon filters:

• Used in most home and community water systems
• Work well for longer-chain PFAS like PFOA and PFOS
• Less effective for shorter-chain PFAS
• Need frequent replacement as they become saturated
• Relatively expensive

Reverse osmosis systems:

• Very effective at removing PFAS
• High energy requirements
• Expensive to install and maintain
• Waste a lot of water in the process

Ion exchange systems:

• Good at removing charged PFAS molecules
• Require special disposal of used resins
• More complex to operate

What This Could Mean for Home Water Treatment

While this research focused on laboratory conditions, it could eventually lead to improvements in home water filtration:

Potential benefits:

• Cheaper filter materials could reduce replacement costs
• More effective removal might mean smaller, more convenient systems
• Longer-lasting filters if the iron remains active even when oxidized

What needs to happen next:

• Testing with different types of PFAS (the study focused on PFOS)
• Development of practical filter designs for home use
• Safety testing to ensure iron particles don’t leach into drinking water
• Scaling up from laboratory to commercial production

The Science Behind the Breakthrough

The researchers used sophisticated testing to understand exactly how the iron powder works:

Key scientific findings:

• The removal wasn’t due to chemical breakdown of PFAS (defluorination)
• It worked through physical adsorption, not chemical bonding
• Both magnetic and non-magnetic parts of the iron contributed to removal
• Acid-washing the iron didn’t significantly improve performance

Why iron works better than carbon: The study suggests that iron provides more effective binding sites for PFAS molecules. The exact mechanism is still being investigated, but the results are clear.

What Happens Next

This research has already gained significant attention in the scientific community – the paper has been viewed over 1,000 times since publication in March 2025.

Immediate next steps:

• Testing with other types of PFAS beyond PFOS
• Investigating why the iron works so much better than carbon
• Developing practical applications for the technology

Longer-term possibilities:

• New types of home water filters using iron-based technology
• Community-scale water treatment systems that are more affordable
• Industrial applications for cleaning up contaminated sites

Research expansion: The Stevens team is planning more studies to understand the mechanisms better, which could lead to even more effective treatment methods.

Current PFAS Treatment Challenges

This breakthrough comes at a critical time when communities are struggling with PFAS contamination:

The existing problems:

• Treatment is expensive, putting it out of reach for many communities
• Some PFAS chemicals are harder to remove than others
• Filter materials need frequent replacement
• Small water systems can’t afford specialized equipment

What iron powder could solve:

• Lower costs make treatment accessible to more communities
• Higher effectiveness means smaller treatment systems
• Durability could reduce maintenance needs

Bottom Line: A Game-Changing Discovery

Scientists at Stevens Institute of Technology have discovered that simple iron powder removes forever chemicals from water 26 times more effectively than the activated carbon used in most current filters. The iron powder is cheaper, works even when it rusts, and could make PFAS treatment accessible to communities that can’t afford current technologies.

The significance:

• This could be the breakthrough needed to make PFAS removal affordable and widespread
• It challenges assumptions about what materials work best for water treatment
• The discovery that rusty iron still works could simplify maintenance

What it means for you:

• Better, cheaper water treatment options may be coming
• Current activated carbon filters are still your best option today
• This research shows that innovation in water treatment is accelerating

Looking ahead: While it will take time to develop commercial applications, this research represents a major step forward in the fight against forever chemicals. It shows that sometimes the best solutions are simpler and cheaper than we expect.

This discovery gives hope to millions of people dealing with PFAS contamination in their drinking water. As scientists continue to refine this technology, we may finally have an affordable way to clean up one of the most persistent pollution problems of our time.

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Stay Updated

• Follow ongoing research – Stevens Institute continues testing this technology
• Current filter options – Activated carbon and reverse osmosis still work today
• Community advocacy – Support PFAS cleanup efforts in your area
• Water testing – Know what’s in your water while waiting for better treatment options

Sources: Stevens Institute of Technology, Environmental Science & Technology journal, ScienceDaily | Last Updated: June 24, 2025

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