Electromagnetic Interference Shielding Material from Grape Seeds: A Sustainable Pyrolysis Route

Grape marcs represent one of the most effectively exploited biowaste resources through cascade valorization approaches, in which byproducts are processed via multiple sequential steps such as extraction, bio-treatment, and pyrolysis. In this study, we present a novel route for producing graphitic carbon (GC) from grape seeds derived from exhausted marc via pyrolysis. We integrate hydropyrolysis and CO2 methanation in a one-pot methodology to valorize both bio-oil and gaseous pyrolysis byproducts. The GC obtained through pyrolysis is evaluated in GC/Polytetrafluoroethylene (PTFE) composites as an electromagnetic interference (EMI) shielding material across the X-band frequency range (8–12 GHz). This work demonstrates a viable and eco-friendly pathway to upcycle abundant biomass into a lightweight, sustainable, and highly tunable material, which represents a promising candidate for effective EMI shielding while simultaneously mitigating process emissions.