Supported by the Global Green Chemistry Innovation and Network Programme (GEF, UNIDO), the second national Gren Hackatnon in Serbia was completed on December 15, 2025.
A reverse-pitch from a Serbian EE-recycling company E-Reciklaza 2010 called for ideas on the selective processing of plastics from WEEE (waste electrical and electronic equipment) that contain toxic additives: phthalates and PBDEs. This inspired a number of solutions proposed for:
- Phthalate extraction/degradation: using supercritical CO₂ (GreenSC team), extraction with less harmful solvents combined with biodegradation (FreeHack team), or photocatalytic degradation (GreenBiVo team).
- PBDE treatment: through extraction and photocatalysis (GreenLaw team) or encapsulation/solidification in geopolymer matrices (Trashformers team), thereby permanently immobilizing toxins within infrastructure materials.
The winning team, FreeHack, addressed the issue of phthalates—toxic substances present in plastics from WEEE (electrical and electronic waste) that hinder recycling. The proposed solution is a long-term sustainable, circular approach enabling more efficient recycling without generating new waste. The methodology consists of five phases:
- Separation of plastics (including PVC) using selective flotation.
- Dechlorination of PVC using ethylene glycol.
- Extraction of phthalates with less harmful solvents (ethanol, ethyl lactate), assisted by microwaves.
- Biodegradation of phthalates via microbiological processes (e.g., Bacillus subtilis).
- Further use of the polymers in polymer concrete.
The final products are carbon electrodes for supercapacitors and phthalate-free polymers, thereby strengthening recycling processes and the circular economy.
