A team of researchers in Spain is transforming old cigarette filters into sound insulation.
5.5 trillion cigarettes are consumed around the world each year and an estimated 4 trillion of those end up discarded in the form of cigarette butts somewhere, on the pavement, in nature or in our oceans. Cigarette butts are actually the most commonly-found type of ocean litter. The filters inside cigarette butts – made of cellulose acetate - aren't biodegradable, and break down into tiny microfibres that are released into the water. The remnants of the tobacco are a danger for the marine animals too, that can ingest them.
What if it was possible to turn such a huge, global waste stream into commercially viable products? A group of researchers in Spain has found a way to do exactly that - turning cigarette butts into soundproofing.
After writing his thesis on the acoustic properties of recycled cork, physics professor Rubén Maderuelo-Sánz joined Valentín Gómez Escobar at the University of Extremadura to continue looking at the sound insulation potential of somewhat unusual materials - this time a cellulose acetate material made from cigarette butts.
Researchers collected cigarette butts from the tops of the bins at the university where they work, before organising them by size and thickness and removing any remnants of tobacco. They ran tests to measure the sound absorption capacities of different brands and cigarette butts of different conditions. They found that the cigarette material could achieve a really high level of absorption - similar and sometimes even high than the one achieved by conventional materials. The team also includes a chemist, a computer scientist, and two mathematicians, who carry out the theoretical modelling of the absorption of the samples and analysing the results.
In the next step, they'll be looking at how the technology can be applied on an industrial scale.