Screening of biohydrogen production based on dark fermentation in the presence of nano-sized Fe2O3 doped metal oxide additives

Increasing the biohydrogen production efficiency through the dark fermentation process has become the biggest challenge in recent years. We aim to enhance biohydrogen production yield by adding nano-sized iron oxide doped metal oxides prepared by the wet impregnation method. Biohydrogen production in the presence of additives was evaluated by the screening of (i) type (Fe₂O₃@Al₂O₃, Fe₂O₃@ZrO₂, and Fe₂O₃@TiO₂) and (ii) concentration (0–200 mg/L) of additives. During the screening of additive type, approximately 14 wt% nano-sized (6 nm) hematite (Fe₂O₃) doped Al₂O₃ showed the highest improvement for biohydrogen production yield among all additives. Batch experiments conducted through dark fermentation demonstrated that 50 mg/L Fe₂O₃@Al₂O₃ addition caused an acceleration in biohydrogen production by 34% and an increment in yield by 15%, despite even low concentrations Al₂O₃ addition inhibited the process.