Optimization and enhancement of biohydrogen production in a single-stage hybrid (dark/photo) fermentation reactor using Fe₃O₄ and TiO₂ nanoparticles

The utilization of nanoparticles to enhance bacterial activity and boost hydrogen production in fermentation processes has gained significant attention due to their unique properties such as high specific surface area and quantum size. This research aimed to improve the biohydrogen yield from food waste by adding iron oxide nanoparticles (Fe3O4) at various concentrations (50, 75, 100, 150, and 200 mg/l) and titanium dioxide (TiO2) at different amounts (25-150 mg/l) to a single-stage hybrid (dark/photo) fermentation reactor. After obtaining the optimal amount of these two nanoparticles, the effect of synergic addition of nanoparticles on hydrogen production yield, was investigated at ratios of Fe3O4/ TiO2 = 50/50 and 100/50 mg/mg. At the ratio of Fe3O4/TiO2 = 100/50, the cumulative hydrogen production and yield of hydrogen have increased from 1613 to 3392 ml and 101.60 to 213.66 mlH2/gVS, respectively, compared to the control experiment. We also found that the COD removal rate has enhanced from 28% to 40.1%. In the optimal value, the bacterial growth lag phase has also remarkably decreased from 8.19 to 4.81 h. (c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.