Engineers at MIT have developed a new filtration membrane capable of removing 99.9% of microplastic particles from drinking water, including nanoplastics smaller than 100 nanometres — a size range that has largely defeated conventional filtration systems. The research, published today in Nature Water, could offer a practical path to microplastic-free municipal water at scale.

How It Works

The membrane is built from a nanofibre scaffold coated with a zwitterionic polymer — a material that carries both positive and negative charges simultaneously. This dual charge creates an electrostatic repulsion effect that physically blocks plastic particles regardless of their surface chemistry, while allowing water molecules to pass through with minimal resistance.

Critically, the membrane operates at standard municipal water pressure without the energy-intensive pumping required by reverse osmosis systems. In lab tests, it maintained 99.9% removal efficiency across particle sizes from 10 nanometres to 5 millimetres after more than 200 filtration cycles without significant degradation.

Scale and Cost

Current microplastic filters either struggle with nanoscale particles or require energy inputs that make them impractical for large-scale deployment. The MIT team estimates their membrane could be manufactured at roughly $0.50 per square metre using existing roll-to-roll polymer processing equipment — comparable to commercial ultrafiltration membranes already deployed at water treatment facilities.

A pilot installation at a municipal treatment plant in Massachusetts is scheduled to begin later this year, with results expected in early 2027.

Why It Matters

Microplastics have been found in human blood, breast milk, and lung tissue in recent years. A 2025 study in the Lancet estimated that the average adult ingests roughly five grams of plastic per week through food and water — equivalent to a credit card. The health effects remain an active area of research, but several studies have linked microplastic exposure to inflammation, hormonal disruption, and cardiovascular damage in animal models.

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MIT Engineers Develop Membrane That Removes 99.9% of Microplastics from Drinking Water