Finer filters from waste

A research group at the University of Granada is working on a project subsidised by the Spanish Ministry of Environmental Issues to make activated charcoal from polymeric waste.

Activated charcoal has a large active surface area due to the numerous nanoscale pores that run through it. A relatively small quantity of charcoal could have the same surface area as a football pitch, according to group coordinator Francisco Javier López Garzón.

Among other applications, activated charcoal is used to manufacture filters for cigarettes, in catalysis processes and to filter harmful substances form the air. The group has been working for four years to cheaply make activated charcoal with a controlled porosity to remove specific pollutants from waste gas.

Commercial activated charcoal is obtained from precursors like olive pits, almond shells or coconut shell. These natural products produce charcoal with varying porosity, which is not selective as to which pollutants it absorbs.