A new study led by a researcher from India looks at a technique to effectively remove carbon dioxide from the air using discarded face masks. The researchers converted face masks into porous activated fibrous adsorbents – materials which capture molecules from a gas, liquid or dissolved solid to a surface, as reported by the Press Trust of India.
According to the study, which was published in the journal Carbon, the adorbents' benefits include a higher adsorption rate, more capturing sites, higher adsorption capacity, and ease of handling compared to granular and powdered materials.
The international team led by associate professor Sunanda Roy, from Alliance University in Bengaluru, developed a way wherein a large number of pores, suitable for heavy carbon dioxide (CO2) adsorption, are formed on the developed fibres of the masks. These fibres are then modified using amine-containing compounds, which contain nitrogen, to promote carbon capture.
The absorption capacity of the new material was higher than found in many contemporary studies. The adsorbed CO2 can be regenerated and the material can be reused several times. The regenerated CO2 can be utilised for green fuel, beverages and dry ice based on the purity, the PTI report explains.
Face masks have been a highly produced medical waste, especially since the covid-19 pandemic hit the world in around three years ago. As they pile up in garbage dumps, their environmental costs are inescapable, adding to the 7,200 tons of medical waste every day that the pandemic was estimated to generate in 2021, as reported by Massachusetts Institute of Technology'.
In recent years, researchers have focused on finding ways to upcycle face masks. In August 2022, a study published in ACS Applied Engineering Materials introduced a method for directly converting surgical polypropylene mask waste into sulfur-doped carbon fibres, which show a high CO2 absorption capacity.
The adsorbents obtained from the recycled face masks in the current study can also be used for separating various dyes from aqueous solutions, the researchers said. Their dye removal properties remained above 94% after nine cycles. The adsorbent can also be used to treat polluted wastewater that is discharged from industries such as textiles and leathers.
The research team included researchers from Birla Institute of Technology in Jharkhand, Newcastle University, Inha University and Hanyang University, both in Korea. The researcher has also developed a graphene foam-based catalyst that can convert CO2 into fuel.
(With inputs from PTI)