Plastics are essential in daily life but pose significant environmental risks due to slow degradation and pollution, especially in water bodies. Acrylonitrile Butadiene Styrene (ABS) used in products like automotive parts and electronics, is currently grouped with other plastics that lack dedicated recycling programs. However, upcoming regulatory changes in Europe aim to improve its recycling.
Traditional disposal methods like incineration and landfilling contribute to pollution, while advanced techniques such as hydrothermal treatment, pyrolysis, and microwave-assisted methods offer promising alternatives for recycling ABS into valuable fuels and chemicals. These processes can reduce plastic waste, preserve natural resources, and lower carbon emissions, contributing to more sustainable product life cycles.
In parallel, pyrolysis processes can contribute to produce solid conductive chars that can be used as backbone for atomically dispersed electrocatalysts containing a transition metal (TM) for a variey of electrochemical processes. Fe-Nx with x = 2,3,4 electrocatalysts has shown to be suitable for oxygen reduction reaction (ORR), especially when operating in alkaline environments. Electrocatalysts were then synthesized using char derived from the pyrolysis of waste ABS funzionalized with iron phthalocyanine and integrated both through a pyrolytic process. To further improve electrical conductivity and the electrocatalytic performance, commercially available carbon black (e.g. Ketjen Black and Vulcan XC72R) were gradually mixed with the plastic-derived char achieving outstanding performance in ORR through rotating ring disk electrode tests.
This study shows a method for recycling ABS with the possibility of harvesting the liquid product and efficient PGM-free electrocatalysts for ORR. This is an alternative method that improve the value of a common waste product within the core of the circular economy.
This work with the title “Upgrading the Waste Acrylonitrile-Butadiene-Styrene into Crude Oil and Highly Efficient Electrocatalysts for Oxygen Reduction Reaction” (doi: 10.1016/j.cej.2025.162236) has been published in the Chemical Engineering Journal (Elsevier, Impact Factor 13.4, 2023 Journal Impact Factor, Journal Citation Reports (Clarivate Analytics, 2023)).
This work was carried out by Mr. Loris Sallaku, Dr. Lorenzo Mirizzi, Dr. Mohsin Muhyuddin, Prof. Simona Binetti, Prof. Piercarlo Mustarelli and Prof. Carlo Santoro (Department of Materials Science, University of Milano-Bicocca), Mr. Niccolò Lamanna and Prof. Luca Zoia (Department of Earth and Environmental Sciences, University of Milano-Bicocca) jointly with the University of Rome “La Sapienza” (Prof. Ernesto Placidi), ENEA (Dr. Valerio Ficca), University of Brescia (Prof. Stefania Federici, Prof. Irene Vassalini) and CNR-ICCOM, Florence (Dr. Enrico Berretti, Dr. Jonathan Filippi, Dr. Alessandro Lavacchi).
This work is a crucial output of the project TESLA “Transformation of plastic waste in Electrocatalysts, Supported by exhausted gases recovery Layout” funded by the Cariplo Foundation, Call for Circular Economy.