car exhaust

Porous material captures harmful pollutants from the air

A material capable of capturing toxic chemicals from the air has been developed by researchers at the University of Limerick in Ireland.

The material is capable of capturing trace amounts of benzene, a toxic pollutant, from the air while using less energy than existing materials, the researchers said.

Benzene is an air toxic typically emitted from gasoline service stations, motor vehicle exhaust and fuel evaporation, the burning of coal and oil, and various other sources.

Volatile organic compounds (VOCs) including benzene are a class of toxic pollutants that cause severe environmental and health issues. Developing technologies to remove benzene from air at trace concentrations and doing it with a low energy footprint are both challenges that have not been overcome until now.

The material that has been created at University of Limerick’s Bernal Institute - named BUT-55

Close-up of the material

Image credit: UL/Bernal

“A family of porous materials – like sponge – have been developed to capture benzene vapour from polluted air and produce a clean air stream for a long working time,” said Researcher Professor Mike Zaworotko.

“These materials could be regenerated easily under mild heating, making them candidates for air purification and environmental remediation.

“Our materials can do much better in both sensitivity and working time than traditional materials.”

The new porous material, which resembles Swiss cheese, has such strong affinity for benzene that it captures the toxic chemical even when present at just 1 part in 100,000.

Because the capture process is based upon physical rather than chemical bonding, the energy footprint of capture and release is much lower than previous generations of materials, the researchers said.

“Breaking up gas mixtures is hard to do. This is especially true for the minor components that comprise air, which include carbon dioxide and water. The properties of our new material show that breaking up is no longer hard to do for benzene,” explained Zaworotko.

Another researcher on the project, Dr Xiang-Jing Kong, explained: “Based on smart design, our materials do well in addressing challenges of both technical and social relevance, such as trace benzene removal from air. This is hard for conventional materials, and thus highlights the charm of porous materials.”

The results suggest that a new generation of bespoke porous materials could be developed to enable a general approach to the capture of toxic chemicals from air.

“Aromatic isomers are difficult to separate in their mixtures with traditional methods, which are always energy-intensive,” Kong added.

“This research opened up possibilities to design porous materials for efficient separation of these chemicals with low energy input as well as removal of other trace pollutants from air.”

In March, the World Health Organisation found that not a single country had managed to meet its annual air quality guidelines.

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