New Lightweight Copper Foam could Revolutionise Filter Technology

According to a new study published on 24 March 2021 in the journal Nano Letters, scientists have created a new lightweight copper-based foam capable of filtering out microscopic particulate matter, including droplets and aerosols containing the coronavirus.

Thanks to its near-100% filtration efficiency, excellent breathability (on par with current N95 masks), as well as easy cleaning, decontamination, and recycling, the foam could soon be used in many diverse products, ranging from respirators to domestic air filtration systems.

Professor Kai Liu from Georgetown University, lead author on the study, has been researching low-density metallic materials since 2010. In this, the latest, effort, Liu and his team used the electrodeposition method to create a 3D scaffold of interconnected, ultra-thin copper nano-wires.

This resulted in a lightweight foam that’s 2% to 30% as dense as copper itself. “It took us a lot of effort to find the optimum structures that are both stable and effective for filtration,” Liu said.

Unlike many of the filter materials currently available on the market, the copper foam is resistant to oils, corrosive substances, high temperatures, and large pressures, making it perfectly suited for use in commercial filters.

Liu emphasised that materials now commonly used for air filtration purposes have various limitations – e.g., fiberglass filters are “fragile, challenging to clean and use”, while N95 masks can “degrade upon exposure to organic solvents, making them difficult to decontaminate and re-use” – which calls for alternative solutions.

In the near future, metallic foam-based filters that are easy to use and recycle could help reduce the massive amount of waste generated by disposable masks and other PPE materials, reaching gargantuan proportions during the pandemic, and help in the fight against climate change, as regular filters take a long time to decompose.

The researchers estimate that the cost of materials needed to produce a single foam-based filter is roughly $2, which is close to price parity. Furthermore, given their reusability, such filters would likely be quite competitive on the market.

Up next, the research team plans to continue exploring different methods of filtration to improve the efficiency of their copper foams prior to commercial roll out.

Source: academictimes.com