Enormous amounts of banknotes are taken out of rotation every year, e.g. € 113 billion in the EU in 2019. The estimated lifetime of each note is around three years, after which polymer-based ones are recycled, and cotton-based ones are incinerated. This has motivated the research team to investigate the chemical recycling of cotton-based banknotes using Ioncell, a technology developed for the sustainable production of synthetic cellulose fibres. Its green colour comes from the original colour of used banknotes.

The research was conducted by Inge Schlapp-Hackl (Aalto University) and Matthias Selinger (Vienna University of Technology) with project team.