Valorization of food waste into renewable fuels via anaerobic digestion and inline CO2 reforming over Ni-based catalysts

Anaerobic digestion (AD) is a promising technology for converting food waste (FW) or other biodegradable organic waste (BOW) into renewable biogas, while dry reforming of methane (DRM) is an environmentally friendly route for converting greenhouse gases into syngas. Moreover, the use of renewable biogas in dry reforming aligns with the global sustainability goals for reducing reliance on fossil fuels in producing important chemicals. In this regard, the present study deals with the valorization of food waste into renewable hydrogen/syngas by integrating AD and DRM. AD of FW was carried out in a lab-scale anaerobic reactor and the resulting biogas was passed over a sorption bed for H₂S removal. It was shown that iron hydroxide-based materials can effectively remove H₂S, thereby providing a clean biogas feed suitable for catalytic dry reforming. Furthermore, it was demonstrated that the Ni catalyst, doped with a small amount of noble metal and supported on MgAl mixed oxides, exhibits superior catalytic performance in reforming of real or model biogas mixtures. The catalyst showed outstanding stability despite online changes in the reaction parameters. This study may provide new insights toward the development of sustainable processes that simultaneously reduce BOW and CO₂, while also generating valuable products.